Midx/upstream #5
Closed
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
derrickstolee
force-pushed
the
midx/upstream
branch
2 times, most recently
from
dbf0f40 to
5e97b74
Compare
derrickstolee
force-pushed
the
midx/upstream
branch
4 times, most recently
from
d6de454 to
8c3cb94
Compare
Signed-off-by: Derrick Stolee <[email protected]>
The multi-pack-index feature generalizes the existing pack-index feature by indexing objects across multiple pack-files. Describe the basic file format, using a 12-byte header followed by a lookup table for a list of "chunks" which will be described later. The file ends with a footer containing a checksum using the hash algorithm. The header allows later versions to create breaking changes by advancing the version number. We can also change the hash algorithm using a different version value. We will add the individual chunk format information as we introduce the code that writes that information. Signed-off-by: Derrick Stolee <[email protected]>
This new 'git multi-pack-index' builtin will be the plumbing access for writing, reading, and checking multi-pack-index files. The initial implementation is a no-op. Signed-off-by: Derrick Stolee <[email protected]>
In anticipation of writing multi-pack-indexes, add a skeleton 'git multi-pack-index write' subcommand and send the options to a write_midx_file() method. Also create a skeleton test script that tests the 'write' subcommand. Signed-off-by: Derrick Stolee <[email protected]>
As we begin writing the multi-pack-index format to disk, start with the basics: the 12-byte header and the 20-byte checksum footer. Start with these basics so we can add the rest of the format in small increments. As we implement the format, we will use a technique to check that our computed offsets within the multi-pack-index file match what we are actually writing. Each method that writes to the hashfile will return the number of bytes written, and we will track that those values match our expectations. Currently, write_midx_header() returns 12, but is not checked. We will check the return value in a later commit. Signed-off-by: Derrick Stolee <[email protected]>
Create a new multi_pack_index struct for loading multi-pack-indexes into memory. Create a test-tool builtin for reading basic information about that multi-pack-index to verify the correct data is written. Signed-off-by: Derrick Stolee <[email protected]>
As we build the multi-pack-index file format, we want to test the format on real repositories. Add tests that create repository data including multiple packfiles with both version 1 and version 2 formats. The current 'git multi-pack-index write' command will always write the same file with no "real" data. This will be expanded in future commits, along with the test expectations. Signed-off-by: Derrick Stolee <[email protected]>
In anticipation of sharing the pack directory listing with the multi-pack-index, generalize prepare_packed_git_one() into for_each_file_in_pack_dir(). Signed-off-by: Derrick Stolee <[email protected]>
When constructing a multi-pack-index file for a given object directory, read the files within the enclosed pack directory and find matches that end with ".idx" and find the correct paired packfile using add_packed_git(). Signed-off-by: Derrick Stolee <[email protected]>
The multi-pack-index needs to track which packfiles it indexes. Store these in our first required chunk. Since filenames are not well structured, add padding to keep good alignment in later chunks. Modify the 'git multi-pack-index read' subcommand to output the existence of the pack-file name chunk. Modify t5319-multi-pack-index.sh to reflect this new output and the new expected number of chunks. Defense in depth: A pattern we are using in the multi-pack-index feature is to verify the data as we write it. We want to ensure we never write invalid data to the multi-pack-index. There are many checks that verify that the values we are writing fit the format definitions. This mainly helps developers while working on the feature, but it can also identify issues that only appear when dealing with very large data sets. These large sets are hard to encode into test cases. Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Before writing a list of objects and their offsets to a multi-pack-index, we need to collect the list of objects contained in the packfiles. There may be multiple copies of some objects, so this list must be deduplicated. It is possible to artificially get into a state where there are many duplicate copies of objects. That can create high memory pressure if we are to create a list of all objects before de-duplication. To reduce this memory pressure without a significant performance drop, automatically group objects by the first byte of their object id. Use the IDX fanout tables to group the data, copy to a local array, then sort. Copy only the de-duplicated entries. Select the duplicate based on the most-recent modified time of a packfile containing the object. Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
The final pair of chunks for the multi-pack-index file stores the object offsets. We default to using 32-bit offsets as in the pack-index version 1 format, but if there exists an offset larger than 32-bits, we use a trick similar to the pack-index version 2 format by storing all offsets at least 2^31 in a 64-bit table; we use the 32-bit table to point into that 64-bit table as necessary. We only store these 64-bit offsets if necessary, so create a test that manipulates a version 2 pack-index to fake a large offset. This allows us to test that the large offset table is created, but the data does not match the actual packfile offsets. The multi-pack-index offset does match the (corrupted) pack-index offset, so a future feature will compare these offsets during a 'verify' step. Signed-off-by: Derrick Stolee <[email protected]>
The core.multiPackIndex config setting controls the multi-pack- index (MIDX) feature. If false, the setting will disable all reads from the multi-pack-index file. Read this config setting in the new prepare_multi_pack_index_one() which is called during prepare_packed_git(). This check is run once per repository. Add comparison commands in t5319-multi-pack-index.sh to check typical Git behavior remains the same as the config setting is turned on and off. This currently includes 'git rev-list' and 'git log' commands to trigger several object database reads. Currently, these would only catch an error in the prepare_multi_pack_index_one(), but with later commits will catch errors in object lookups, abbreviations, and approximate object counts. Signed-off-by: Derrick Stolee <[email protected]> midx: prepare midxed_git struct Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
Due to how Windows handles replacing a lockfile when there is an open handle, create the close_midx() method to close the existing midx before writing the new one. Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
The multi-pack-index, when present, tracks the existence of objects and their offsets within a list of packfiles. This allows us to use the multi-pack-index for object lookups, abbreviations, and object counts. When the multi-pack-index tracks a packfile, then we do not need to add that packfile to the packed_git linked list or the MRU list. We still need to load the packfiles that are not tracked by the multi-pack-index. Signed-off-by: Derrick Stolee <[email protected]>
Signed-off-by: Derrick Stolee <[email protected]>
If a 'git repack' command replaces existing packfiles, then we must clear the existing multi-pack-index before moving the packfiles it references. Signed-off-by: Derrick Stolee <[email protected]>
derrickstolee
force-pushed
the
midx/upstream
branch
from
8c3cb94 to
f3f9363
Compare
gitgitgadget bot
pushed a commit
that referenced
this pull request
Jun 17, 2024
Memory sanitizer (msan) is detecting a use of an uninitialized variable
(`size`) in `read_attr_from_index`:
==2268==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x5651f3416504 in read_attr_from_index git/attr.c:868:11
#1 0x5651f3415530 in read_attr git/attr.c
#2 0x5651f3413d74 in bootstrap_attr_stack git/attr.c:968:6
#3 0x5651f3413d74 in prepare_attr_stack git/attr.c:1004:2
#4 0x5651f3413d74 in collect_some_attrs git/attr.c:1199:2
#5 0x5651f3413144 in git_check_attr git/attr.c:1345:2
#6 0x5651f34728da in convert_attrs git/convert.c:1320:2
#7 0x5651f3473425 in would_convert_to_git_filter_fd git/convert.c:1373:2
#8 0x5651f357a35e in index_fd git/object-file.c:2630:34
#9 0x5651f357aa15 in index_path git/object-file.c:2657:7
#10 0x5651f35db9d9 in add_to_index git/read-cache.c:766:7
#11 0x5651f35dc170 in add_file_to_index git/read-cache.c:799:9
#12 0x5651f321f9b2 in add_files git/builtin/add.c:346:7
#13 0x5651f321f9b2 in cmd_add git/builtin/add.c:565:18
#14 0x5651f321d327 in run_builtin git/git.c:474:11
#15 0x5651f321bc9e in handle_builtin git/git.c:729:3
#16 0x5651f321a792 in run_argv git/git.c:793:4
#17 0x5651f321a792 in cmd_main git/git.c:928:19
#18 0x5651f33dde1f in main git/common-main.c:62:11
The issue exists because `size` is an output parameter from
`read_blob_data_from_index`, but it's only modified if
`read_blob_data_from_index` returns non-NULL. The read of `size` when
calling `read_attr_from_buf` unconditionally may read from an
uninitialized value. `read_attr_from_buf` checks that `buf` is non-NULL
before reading from `size`, but by then it's already too late: the
uninitialized read will have happened already. Furthermore, there's no
guarantee that the compiler won't reorder things so that it checks
`size` before checking `!buf`.
Make the call to `read_attr_from_buf` conditional on `buf` being
non-NULL, ensuring that `size` is not read if it's never set.
Signed-off-by: Kyle Lippincott <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Aug 19, 2024
It was recently reported that concurrent reads and writes may cause the
reftable backend to segfault. The root cause of this is that we do not
properly keep track of reftable readers across reloads.
Suppose that you have a reftable iterator and then decide to reload the
stack while iterating through the iterator. When the stack has been
rewritten since we have created the iterator, then we would end up
discarding a subset of readers that may still be in use by the iterator.
The consequence is that we now try to reference deallocated memory,
which of course segfaults.
One way to trigger this is in t5616, where some background maintenance
jobs have been leaking from one test into another. This leads to stack
traces like the following one:
+ git -c protocol.version=0 -C pc1 fetch --filter=blob:limit=29999 --refetch origin
AddressSanitizer:DEADLYSIGNAL
=================================================================
==657994==ERROR: AddressSanitizer: SEGV on unknown address 0x7fa0f0ec6089 (pc 0x55f23e52ddf9 bp
0x7ffe7bfa1700 sp 0x7ffe7bfa1700 T0)
==657994==The signal is caused by a READ memory access.
#0 0x55f23e52ddf9 in get_var_int reftable/record.c:29
#1 0x55f23e53295e in reftable_decode_keylen reftable/record.c:170
#2 0x55f23e532cc0 in reftable_decode_key reftable/record.c:194
#3 0x55f23e54e72e in block_iter_next reftable/block.c:398
#4 0x55f23e5573dc in table_iter_next_in_block reftable/reader.c:240
#5 0x55f23e5573dc in table_iter_next reftable/reader.c:355
#6 0x55f23e5573dc in table_iter_next reftable/reader.c:339
#7 0x55f23e551283 in merged_iter_advance_subiter reftable/merged.c:69
#8 0x55f23e55169e in merged_iter_next_entry reftable/merged.c:123
#9 0x55f23e55169e in merged_iter_next_void reftable/merged.c:172
#10 0x55f23e537625 in reftable_iterator_next_ref reftable/generic.c:175
#11 0x55f23e2cf9c6 in reftable_ref_iterator_advance refs/reftable-backend.c:464
#12 0x55f23e2d996e in ref_iterator_advance refs/iterator.c:13
#13 0x55f23e2d996e in do_for_each_ref_iterator refs/iterator.c:452
#14 0x55f23dca6767 in get_ref_map builtin/fetch.c:623
#15 0x55f23dca6767 in do_fetch builtin/fetch.c:1659
#16 0x55f23dca6767 in fetch_one builtin/fetch.c:2133
#17 0x55f23dca6767 in cmd_fetch builtin/fetch.c:2432
#18 0x55f23dba7764 in run_builtin git.c:484
#19 0x55f23dba7764 in handle_builtin git.c:741
#20 0x55f23dbab61e in run_argv git.c:805
#21 0x55f23dbab61e in cmd_main git.c:1000
#22 0x55f23dba4781 in main common-main.c:64
#23 0x7fa0f063fc89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#24 0x7fa0f063fd44 in __libc_start_main_impl ../csu/libc-start.c:360
#25 0x55f23dba6ad0 in _start (git+0xadfad0) (BuildId: 803b2b7f59beb03d7849fb8294a8e2145dd4aa27)
While it is somewhat awkward that the maintenance processes survive
tests in the first place, it is totally expected that reftables should
work alright with concurrent writers. Seemingly they don't.
The only underlying resource that we need to care about in this context
is the reftable reader, which is responsible for reading a single table
from disk. These readers get discarded immediately (unless reused) when
calling `reftable_stack_reload()`, which is wrong. We can only close
them once we know that there are no iterators using them anymore.
Prepare for a fix by converting the reftable readers to be refcounted.
Reported-by: Jeff King <[email protected]>
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Aug 22, 2024
It was recently reported that concurrent reads and writes may cause the
reftable backend to segfault. The root cause of this is that we do not
properly keep track of reftable readers across reloads.
Suppose that you have a reftable iterator and then decide to reload the
stack while iterating through the iterator. When the stack has been
rewritten since we have created the iterator, then we would end up
discarding a subset of readers that may still be in use by the iterator.
The consequence is that we now try to reference deallocated memory,
which of course segfaults.
One way to trigger this is in t5616, where some background maintenance
jobs have been leaking from one test into another. This leads to stack
traces like the following one:
+ git -c protocol.version=0 -C pc1 fetch --filter=blob:limit=29999 --refetch origin
AddressSanitizer:DEADLYSIGNAL
=================================================================
==657994==ERROR: AddressSanitizer: SEGV on unknown address 0x7fa0f0ec6089 (pc 0x55f23e52ddf9 bp
0x7ffe7bfa1700 sp 0x7ffe7bfa1700 T0)
==657994==The signal is caused by a READ memory access.
#0 0x55f23e52ddf9 in get_var_int reftable/record.c:29
#1 0x55f23e53295e in reftable_decode_keylen reftable/record.c:170
#2 0x55f23e532cc0 in reftable_decode_key reftable/record.c:194
#3 0x55f23e54e72e in block_iter_next reftable/block.c:398
#4 0x55f23e5573dc in table_iter_next_in_block reftable/reader.c:240
#5 0x55f23e5573dc in table_iter_next reftable/reader.c:355
#6 0x55f23e5573dc in table_iter_next reftable/reader.c:339
#7 0x55f23e551283 in merged_iter_advance_subiter reftable/merged.c:69
#8 0x55f23e55169e in merged_iter_next_entry reftable/merged.c:123
#9 0x55f23e55169e in merged_iter_next_void reftable/merged.c:172
#10 0x55f23e537625 in reftable_iterator_next_ref reftable/generic.c:175
#11 0x55f23e2cf9c6 in reftable_ref_iterator_advance refs/reftable-backend.c:464
#12 0x55f23e2d996e in ref_iterator_advance refs/iterator.c:13
#13 0x55f23e2d996e in do_for_each_ref_iterator refs/iterator.c:452
#14 0x55f23dca6767 in get_ref_map builtin/fetch.c:623
#15 0x55f23dca6767 in do_fetch builtin/fetch.c:1659
#16 0x55f23dca6767 in fetch_one builtin/fetch.c:2133
#17 0x55f23dca6767 in cmd_fetch builtin/fetch.c:2432
#18 0x55f23dba7764 in run_builtin git.c:484
#19 0x55f23dba7764 in handle_builtin git.c:741
#20 0x55f23dbab61e in run_argv git.c:805
#21 0x55f23dbab61e in cmd_main git.c:1000
#22 0x55f23dba4781 in main common-main.c:64
#23 0x7fa0f063fc89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#24 0x7fa0f063fd44 in __libc_start_main_impl ../csu/libc-start.c:360
#25 0x55f23dba6ad0 in _start (git+0xadfad0) (BuildId: 803b2b7f59beb03d7849fb8294a8e2145dd4aa27)
While it is somewhat awkward that the maintenance processes survive
tests in the first place, it is totally expected that reftables should
work alright with concurrent writers. Seemingly they don't.
The only underlying resource that we need to care about in this context
is the reftable reader, which is responsible for reading a single table
from disk. These readers get discarded immediately (unless reused) when
calling `reftable_stack_reload()`, which is wrong. We can only close
them once we know that there are no iterators using them anymore.
Prepare for a fix by converting the reftable readers to be refcounted.
Reported-by: Jeff King <[email protected]>
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Aug 23, 2024
It was recently reported that concurrent reads and writes may cause the
reftable backend to segfault. The root cause of this is that we do not
properly keep track of reftable readers across reloads.
Suppose that you have a reftable iterator and then decide to reload the
stack while iterating through the iterator. When the stack has been
rewritten since we have created the iterator, then we would end up
discarding a subset of readers that may still be in use by the iterator.
The consequence is that we now try to reference deallocated memory,
which of course segfaults.
One way to trigger this is in t5616, where some background maintenance
jobs have been leaking from one test into another. This leads to stack
traces like the following one:
+ git -c protocol.version=0 -C pc1 fetch --filter=blob:limit=29999 --refetch origin
AddressSanitizer:DEADLYSIGNAL
=================================================================
==657994==ERROR: AddressSanitizer: SEGV on unknown address 0x7fa0f0ec6089 (pc 0x55f23e52ddf9 bp
0x7ffe7bfa1700 sp 0x7ffe7bfa1700 T0)
==657994==The signal is caused by a READ memory access.
#0 0x55f23e52ddf9 in get_var_int reftable/record.c:29
#1 0x55f23e53295e in reftable_decode_keylen reftable/record.c:170
#2 0x55f23e532cc0 in reftable_decode_key reftable/record.c:194
#3 0x55f23e54e72e in block_iter_next reftable/block.c:398
#4 0x55f23e5573dc in table_iter_next_in_block reftable/reader.c:240
#5 0x55f23e5573dc in table_iter_next reftable/reader.c:355
#6 0x55f23e5573dc in table_iter_next reftable/reader.c:339
#7 0x55f23e551283 in merged_iter_advance_subiter reftable/merged.c:69
#8 0x55f23e55169e in merged_iter_next_entry reftable/merged.c:123
#9 0x55f23e55169e in merged_iter_next_void reftable/merged.c:172
#10 0x55f23e537625 in reftable_iterator_next_ref reftable/generic.c:175
#11 0x55f23e2cf9c6 in reftable_ref_iterator_advance refs/reftable-backend.c:464
#12 0x55f23e2d996e in ref_iterator_advance refs/iterator.c:13
#13 0x55f23e2d996e in do_for_each_ref_iterator refs/iterator.c:452
#14 0x55f23dca6767 in get_ref_map builtin/fetch.c:623
#15 0x55f23dca6767 in do_fetch builtin/fetch.c:1659
#16 0x55f23dca6767 in fetch_one builtin/fetch.c:2133
#17 0x55f23dca6767 in cmd_fetch builtin/fetch.c:2432
#18 0x55f23dba7764 in run_builtin git.c:484
#19 0x55f23dba7764 in handle_builtin git.c:741
#20 0x55f23dbab61e in run_argv git.c:805
#21 0x55f23dbab61e in cmd_main git.c:1000
#22 0x55f23dba4781 in main common-main.c:64
#23 0x7fa0f063fc89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#24 0x7fa0f063fd44 in __libc_start_main_impl ../csu/libc-start.c:360
#25 0x55f23dba6ad0 in _start (git+0xadfad0) (BuildId: 803b2b7f59beb03d7849fb8294a8e2145dd4aa27)
While it is somewhat awkward that the maintenance processes survive
tests in the first place, it is totally expected that reftables should
work alright with concurrent writers. Seemingly they don't.
The only underlying resource that we need to care about in this context
is the reftable reader, which is responsible for reading a single table
from disk. These readers get discarded immediately (unless reused) when
calling `reftable_stack_reload()`, which is wrong. We can only close
them once we know that there are no iterators using them anymore.
Prepare for a fix by converting the reftable readers to be refcounted.
Reported-by: Jeff King <[email protected]>
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Oct 5, 2024
The incremental MIDX bitmap work was done prior to 9d4855e (midx-write: fix leaking buffer, 2024-09-30), and causes test failures in t5334 in a post-9d4855eef3 world. The leak looks like: Direct leak of 264 byte(s) in 1 object(s) allocated from: #0 0x7f6bcd87eaca in calloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:90 #1 0x55ad1428e8a4 in xcalloc wrapper.c:151 #2 0x55ad14199e16 in prepare_midx_bitmap_git pack-bitmap.c:742 #3 0x55ad14199447 in open_midx_bitmap_1 pack-bitmap.c:507 #4 0x55ad14199cca in open_midx_bitmap pack-bitmap.c:704 #5 0x55ad14199d44 in open_bitmap pack-bitmap.c:717 #6 0x55ad14199dc2 in prepare_bitmap_git pack-bitmap.c:733 #7 0x55ad1419e496 in test_bitmap_walk pack-bitmap.c:2698 #8 0x55ad14047b0b in cmd_rev_list builtin/rev-list.c:629 #9 0x55ad13f71cd6 in run_builtin git.c:487 #10 0x55ad13f72132 in handle_builtin git.c:756 #11 0x55ad13f72380 in run_argv git.c:826 #12 0x55ad13f728f4 in cmd_main git.c:961 #13 0x55ad1407d3ae in main common-main.c:64 #14 0x7f6bcd5f0c89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58 #15 0x7f6bcd5f0d44 in __libc_start_main_impl ../csu/libc-start.c:360 #16 0x55ad13f6ff90 in _start (git+0x1ef90) (BuildId: 3e63cdd415f1d185b21da3035cb48332510dddce) , and is a result of us not freeing the resources corresponding to the bitmap's base layer, if one was present. Rectify that leak by calling the newly-introduced free_bitmap_index() function on the base layer to ensure that its resources are also freed. Signed-off-by: Taylor Blau <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Oct 18, 2024
This one is a little bit more curious. In t6112, we have a test that
exercises the `git rev-list --filter` option with invalid filters. We
execute git-rev-list(1) via `test_must_fail`, which means that we check
for leaks even though Git exits with an error code. This causes the
following leak:
Direct leak of 27 byte(s) in 1 object(s) allocated from:
#0 0x5555555e6946 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x5555558fb4b6 in xrealloc wrapper.c:137:8
#2 0x5555558b6e06 in strbuf_grow strbuf.c:112:2
#3 0x5555558b7550 in strbuf_add strbuf.c:311:2
#4 0x5555557c1a88 in strbuf_addstr strbuf.h:310:2
#5 0x5555557c1d4c in parse_list_objects_filter list-objects-filter-options.c:261:3
#6 0x555555885ead in handle_revision_pseudo_opt revision.c:2899:3
#7 0x555555884e20 in setup_revisions revision.c:3014:11
#8 0x5555556c4b42 in cmd_rev_list builtin/rev-list.c:588:9
#9 0x5555555ec5e3 in run_builtin git.c:483:11
#10 0x5555555eb1e4 in handle_builtin git.c:749:13
#11 0x5555555ec001 in run_argv git.c:819:4
#12 0x5555555eaf94 in cmd_main git.c:954:19
#13 0x5555556fd569 in main common-main.c:64:11
#14 0x7ffff7ca714d in __libc_start_call_main (.../lib/libc.so.6+0x2a14d)
#15 0x7ffff7ca7208 in __libc_start_main@GLIBC_2.2.5 (.../libc.so.6+0x2a208)
#16 0x5555555ad064 in _start (git+0x59064)
This leak is valid, as we call `die()` and do not clean up the memory at
all. But what's curious is that this is the only leak reported, because
we don't clean up any other allocated memory, either, and I have no idea
why the leak sanitizer treats this buffer specially.
In any case, we can work around the leak by shuffling things around a
bit. Instead of calling `gently_parse_list_objects_filter()` and dying
after we have modified the filter spec, we simply do so beforehand. Like
this we don't allocate the buffer in the error case, which makes the
reported leak go away.
It's not pretty, but it manages to make t6112 leak free.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Oct 21, 2024
This one is a little bit more curious. In t6112, we have a test that
exercises the `git rev-list --filter` option with invalid filters. We
execute git-rev-list(1) via `test_must_fail`, which means that we check
for leaks even though Git exits with an error code. This causes the
following leak:
Direct leak of 27 byte(s) in 1 object(s) allocated from:
#0 0x5555555e6946 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x5555558fb4b6 in xrealloc wrapper.c:137:8
#2 0x5555558b6e06 in strbuf_grow strbuf.c:112:2
#3 0x5555558b7550 in strbuf_add strbuf.c:311:2
#4 0x5555557c1a88 in strbuf_addstr strbuf.h:310:2
#5 0x5555557c1d4c in parse_list_objects_filter list-objects-filter-options.c:261:3
#6 0x555555885ead in handle_revision_pseudo_opt revision.c:2899:3
#7 0x555555884e20 in setup_revisions revision.c:3014:11
#8 0x5555556c4b42 in cmd_rev_list builtin/rev-list.c:588:9
#9 0x5555555ec5e3 in run_builtin git.c:483:11
#10 0x5555555eb1e4 in handle_builtin git.c:749:13
#11 0x5555555ec001 in run_argv git.c:819:4
#12 0x5555555eaf94 in cmd_main git.c:954:19
#13 0x5555556fd569 in main common-main.c:64:11
#14 0x7ffff7ca714d in __libc_start_call_main (.../lib/libc.so.6+0x2a14d)
#15 0x7ffff7ca7208 in __libc_start_main@GLIBC_2.2.5 (.../libc.so.6+0x2a208)
#16 0x5555555ad064 in _start (git+0x59064)
This leak is valid, as we call `die()` and do not clean up the memory at
all. But what's curious is that this is the only leak reported, because
we don't clean up any other allocated memory, either, and I have no idea
why the leak sanitizer treats this buffer specially.
In any case, we can work around the leak by shuffling things around a
bit. Instead of calling `gently_parse_list_objects_filter()` and dying
after we have modified the filter spec, we simply do so beforehand. Like
this we don't allocate the buffer in the error case, which makes the
reported leak go away.
It's not pretty, but it manages to make t6112 leak free.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Nov 5, 2024
This one is a little bit more curious. In t6112, we have a test that
exercises the `git rev-list --filter` option with invalid filters. We
execute git-rev-list(1) via `test_must_fail`, which means that we check
for leaks even though Git exits with an error code. This causes the
following leak:
Direct leak of 27 byte(s) in 1 object(s) allocated from:
#0 0x5555555e6946 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x5555558fb4b6 in xrealloc wrapper.c:137:8
#2 0x5555558b6e06 in strbuf_grow strbuf.c:112:2
#3 0x5555558b7550 in strbuf_add strbuf.c:311:2
#4 0x5555557c1a88 in strbuf_addstr strbuf.h:310:2
#5 0x5555557c1d4c in parse_list_objects_filter list-objects-filter-options.c:261:3
#6 0x555555885ead in handle_revision_pseudo_opt revision.c:2899:3
#7 0x555555884e20 in setup_revisions revision.c:3014:11
#8 0x5555556c4b42 in cmd_rev_list builtin/rev-list.c:588:9
#9 0x5555555ec5e3 in run_builtin git.c:483:11
#10 0x5555555eb1e4 in handle_builtin git.c:749:13
#11 0x5555555ec001 in run_argv git.c:819:4
#12 0x5555555eaf94 in cmd_main git.c:954:19
#13 0x5555556fd569 in main common-main.c:64:11
#14 0x7ffff7ca714d in __libc_start_call_main (.../lib/libc.so.6+0x2a14d)
#15 0x7ffff7ca7208 in __libc_start_main@GLIBC_2.2.5 (.../libc.so.6+0x2a208)
#16 0x5555555ad064 in _start (git+0x59064)
This leak is valid, as we call `die()` and do not clean up the memory at
all. But what's curious is that this is the only leak reported, because
we don't clean up any other allocated memory, either, and I have no idea
why the leak sanitizer treats this buffer specially.
In any case, we can work around the leak by shuffling things around a
bit. Instead of calling `gently_parse_list_objects_filter()` and dying
after we have modified the filter spec, we simply do so beforehand. Like
this we don't allocate the buffer in the error case, which makes the
reported leak go away.
It's not pretty, but it manages to make t6112 leak free.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Nov 7, 2024
When running t5601 with the leak checker enabled we can see a hang in
our CI systems. This hang seems to be system-specific, as I cannot
reproduce it on my own machine.
As it turns out, the issue is in those testcases that exercise cloning
of `~repo`-style paths. All of the testcases that hang eventually end up
interpreting "repo" as the username and will call getpwnam(3p) with that
username. That should of course be fine, and getpwnam(3p) should just
return an error. But instead, the leak sanitizer seems to be recursing
while handling a call to `free()` in the NSS modules:
#0 0x00007ffff7fd98d5 in _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:720
#1 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#2 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#3 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#4 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#5 __lsan::lsan_free (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
...
#261505 0x00007ffff7fd99f2 in free (ptr=<optimized out>) at ../include/rtld-malloc.h:50
#261506 _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:822
#261507 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#261508 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#261509 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#261510 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#261511 __lsan::lsan_free (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
#261512 0x00007ffff793da25 in module_load (module=0x515000000280) at ./nss/nss_module.c:188
#261513 0x00007ffff793dee5 in __nss_module_load (module=0x515000000280) at ./nss/nss_module.c:302
#261514 __nss_module_get_function (module=0x515000000280, name=name@entry=0x7ffff79b9128 "getpwnam_r") at ./nss/nss_module.c:328
#261515 0x00007ffff793e741 in __GI___nss_lookup_function (fct_name=<optimized out>, ni=<optimized out>) at ./nss/nsswitch.c:137
#261516 __GI___nss_next2 (ni=ni@entry=0x7fffffffa458, fct_name=fct_name@entry=0x7ffff79b9128 "getpwnam_r", fct2_name=fct2_name@entry=0x0, fctp=fctp@entry=0x7fffffffa460,
status=status@entry=0, all_values=all_values@entry=0) at ./nss/nsswitch.c:120
#261517 0x00007ffff794c6a7 in __getpwnam_r (name=name@entry=0x501000000060 "repo", resbuf=resbuf@entry=0x7ffff79fb320 <resbuf>, buffer=<optimized out>,
buflen=buflen@entry=1024, result=result@entry=0x7fffffffa4b0) at ../nss/getXXbyYY_r.c:343
#261518 0x00007ffff794c4d8 in getpwnam (name=0x501000000060 "repo") at ../nss/getXXbyYY.c:140
#261519 0x00005555557e37ff in getpw_str (username=0x5020000001a1 "repo", len=4) at path.c:613
#261520 0x00005555557e3937 in interpolate_path (path=0x5020000001a0 "~repo", real_home=0) at path.c:654
#261521 0x00005555557e3aea in enter_repo (path=0x501000000040 "~repo", strict=0) at path.c:718
#261522 0x000055555568f0ba in cmd_upload_pack (argc=1, argv=0x502000000100, prefix=0x0, repo=0x0) at builtin/upload-pack.c:57
#261523 0x0000555555575ba8 in run_builtin (p=0x555555a20c98 <commands+3192>, argc=2, argv=0x502000000100, repo=0x555555a53b20 <the_repo>) at git.c:481
#261524 0x0000555555576067 in handle_builtin (args=0x7fffffffaab0) at git.c:742
#261525 0x000055555557678d in cmd_main (argc=2, argv=0x7fffffffac58) at git.c:912
#261526 0x00005555556963cd in main (argc=2, argv=0x7fffffffac58) at common-main.c:64
Note that this stack is more than 260000 function calls deep. Run under
the debugger this will eventually segfault, but in our CI systems it
seems like this just hangs forever.
I assume that this is a bug either in the leak sanitizer or in glibc, as
I cannot reproduce it on my machine. In any case, let's work around the
bug for now by marking those tests with the "!SANITIZE_LEAK" prereq.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Nov 12, 2024
When running t5601 with the leak checker enabled we can see a hang in
our CI systems. This hang seems to be system-specific, as I cannot
reproduce it on my own machine.
As it turns out, the issue is in those testcases that exercise cloning
of `~repo`-style paths. All of the testcases that hang eventually end up
interpreting "repo" as the username and will call getpwnam(3p) with that
username. That should of course be fine, and getpwnam(3p) should just
return an error. But instead, the leak sanitizer seems to be recursing
while handling a call to `free()` in the NSS modules:
#0 0x00007ffff7fd98d5 in _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:720
#1 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#2 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#3 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#4 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#5 __lsan::lsan_free (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
...
#261505 0x00007ffff7fd99f2 in free (ptr=<optimized out>) at ../include/rtld-malloc.h:50
#261506 _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:822
#261507 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#261508 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#261509 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#261510 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#261511 __lsan::lsan_free (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
#261512 0x00007ffff793da25 in module_load (module=0x515000000280) at ./nss/nss_module.c:188
#261513 0x00007ffff793dee5 in __nss_module_load (module=0x515000000280) at ./nss/nss_module.c:302
#261514 __nss_module_get_function (module=0x515000000280, name=name@entry=0x7ffff79b9128 "getpwnam_r") at ./nss/nss_module.c:328
#261515 0x00007ffff793e741 in __GI___nss_lookup_function (fct_name=<optimized out>, ni=<optimized out>) at ./nss/nsswitch.c:137
#261516 __GI___nss_next2 (ni=ni@entry=0x7fffffffa458, fct_name=fct_name@entry=0x7ffff79b9128 "getpwnam_r", fct2_name=fct2_name@entry=0x0, fctp=fctp@entry=0x7fffffffa460,
status=status@entry=0, all_values=all_values@entry=0) at ./nss/nsswitch.c:120
#261517 0x00007ffff794c6a7 in __getpwnam_r (name=name@entry=0x501000000060 "repo", resbuf=resbuf@entry=0x7ffff79fb320 <resbuf>, buffer=<optimized out>,
buflen=buflen@entry=1024, result=result@entry=0x7fffffffa4b0) at ../nss/getXXbyYY_r.c:343
#261518 0x00007ffff794c4d8 in getpwnam (name=0x501000000060 "repo") at ../nss/getXXbyYY.c:140
#261519 0x00005555557e37ff in getpw_str (username=0x5020000001a1 "repo", len=4) at path.c:613
#261520 0x00005555557e3937 in interpolate_path (path=0x5020000001a0 "~repo", real_home=0) at path.c:654
#261521 0x00005555557e3aea in enter_repo (path=0x501000000040 "~repo", strict=0) at path.c:718
#261522 0x000055555568f0ba in cmd_upload_pack (argc=1, argv=0x502000000100, prefix=0x0, repo=0x0) at builtin/upload-pack.c:57
#261523 0x0000555555575ba8 in run_builtin (p=0x555555a20c98 <commands+3192>, argc=2, argv=0x502000000100, repo=0x555555a53b20 <the_repo>) at git.c:481
#261524 0x0000555555576067 in handle_builtin (args=0x7fffffffaab0) at git.c:742
#261525 0x000055555557678d in cmd_main (argc=2, argv=0x7fffffffac58) at git.c:912
#261526 0x00005555556963cd in main (argc=2, argv=0x7fffffffac58) at common-main.c:64
Note that this stack is more than 260000 function calls deep. Run under
the debugger this will eventually segfault, but in our CI systems it
seems like this just hangs forever.
I assume that this is a bug either in the leak sanitizer or in glibc, as
I cannot reproduce it on my machine. In any case, let's work around the
bug for now by marking those tests with the "!SANITIZE_LEAK" prereq.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Nov 21, 2024
When running t5601 with the leak checker enabled we can see a hang in
our CI systems. This hang seems to be system-specific, as I cannot
reproduce it on my own machine.
As it turns out, the issue is in those testcases that exercise cloning
of `~repo`-style paths. All of the testcases that hang eventually end up
interpreting "repo" as the username and will call getpwnam(3p) with that
username. That should of course be fine, and getpwnam(3p) should just
return an error. But instead, the leak sanitizer seems to be recursing
while handling a call to `free()` in the NSS modules:
#0 0x00007ffff7fd98d5 in _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:720
#1 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#2 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#3 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#4 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#5 __lsan::lsan_free (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
...
#261505 0x00007ffff7fd99f2 in free (ptr=<optimized out>) at ../include/rtld-malloc.h:50
#261506 _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:822
#261507 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#261508 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#261509 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#261510 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#261511 __lsan::lsan_free (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
#261512 0x00007ffff793da25 in module_load (module=0x515000000280) at ./nss/nss_module.c:188
#261513 0x00007ffff793dee5 in __nss_module_load (module=0x515000000280) at ./nss/nss_module.c:302
#261514 __nss_module_get_function (module=0x515000000280, name=name@entry=0x7ffff79b9128 "getpwnam_r") at ./nss/nss_module.c:328
#261515 0x00007ffff793e741 in __GI___nss_lookup_function (fct_name=<optimized out>, ni=<optimized out>) at ./nss/nsswitch.c:137
#261516 __GI___nss_next2 (ni=ni@entry=0x7fffffffa458, fct_name=fct_name@entry=0x7ffff79b9128 "getpwnam_r", fct2_name=fct2_name@entry=0x0, fctp=fctp@entry=0x7fffffffa460,
status=status@entry=0, all_values=all_values@entry=0) at ./nss/nsswitch.c:120
#261517 0x00007ffff794c6a7 in __getpwnam_r (name=name@entry=0x501000000060 "repo", resbuf=resbuf@entry=0x7ffff79fb320 <resbuf>, buffer=<optimized out>,
buflen=buflen@entry=1024, result=result@entry=0x7fffffffa4b0) at ../nss/getXXbyYY_r.c:343
#261518 0x00007ffff794c4d8 in getpwnam (name=0x501000000060 "repo") at ../nss/getXXbyYY.c:140
#261519 0x00005555557e37ff in getpw_str (username=0x5020000001a1 "repo", len=4) at path.c:613
#261520 0x00005555557e3937 in interpolate_path (path=0x5020000001a0 "~repo", real_home=0) at path.c:654
#261521 0x00005555557e3aea in enter_repo (path=0x501000000040 "~repo", strict=0) at path.c:718
#261522 0x000055555568f0ba in cmd_upload_pack (argc=1, argv=0x502000000100, prefix=0x0, repo=0x0) at builtin/upload-pack.c:57
#261523 0x0000555555575ba8 in run_builtin (p=0x555555a20c98 <commands+3192>, argc=2, argv=0x502000000100, repo=0x555555a53b20 <the_repo>) at git.c:481
#261524 0x0000555555576067 in handle_builtin (args=0x7fffffffaab0) at git.c:742
#261525 0x000055555557678d in cmd_main (argc=2, argv=0x7fffffffac58) at git.c:912
#261526 0x00005555556963cd in main (argc=2, argv=0x7fffffffac58) at common-main.c:64
Note that this stack is more than 260000 function calls deep. Run under
the debugger this will eventually segfault, but in our CI systems it
seems like this just hangs forever.
I assume that this is a bug either in the leak sanitizer or in glibc, as
I cannot reproduce it on my machine. In any case, let's work around the
bug for now by marking those tests with the "!SANITIZE_LEAK" prereq.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Dec 30, 2024
There's a race with LSan when spawning threads and one of the threads
calls die(). We worked around one such problem with index-pack in the
previous commit, but it exists in git-grep, too. You can see it with:
make SANITIZE=leak THREAD_BARRIER_PTHREAD=YesOnLinux
cd t
./t0003-attributes.sh --stress
which fails pretty quickly with:
==git==4096424==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 32 byte(s) in 1 object(s) allocated from:
#0 0x7f906de14556 in realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
#1 0x7f906dc9d2c1 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
#2 0x7f906de2500d in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
#3 0x7f906de25187 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:614
#4 0x7f906de17d18 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:53
#5 0x7f906de143a9 in ThreadStartFunc<false> ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:431
#6 0x7f906dc9bf51 in start_thread nptl/pthread_create.c:447
#7 0x7f906dd1a677 in __clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78
As with the previous commit, we can fix this by inserting a barrier that
makes sure all threads have finished their setup before continuing. But
there's one twist in this case: the thread which calls die() is not one
of the worker threads, but the main thread itself!
So we need the main thread to wait in the barrier, too, until all
threads have gotten to it. And thus we initialize the barrier for
num_threads+1, to account for all of the worker threads plus the main
one.
If we then test as above, t0003 should run indefinitely.
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Dec 30, 2024
In 1b9e9be (csum-file.c: use unsafe SHA-1 implementation when available, 2024-09-26) we have converted our `struct hashfile` to use the unsafe SHA1 backend, which results in a significant speedup. One needs to be careful with how to use that structure now though because callers need to consistently use either the safe or unsafe variants of SHA1, as otherwise one can easily trigger corruption. As it turns out, we have one inconsistent usage in our tree because we directly initialize `struct hashfile_checkpoint::ctx` with the safe variant of SHA1, but end up writing to that context with the unsafe ones. This went unnoticed so far because our CI systems do not exercise different hash functions for these two backends, and consequently safe and unsafe variants are equivalent. But when using SHA1DC as safe and OpenSSL as unsafe backend this leads to a crash an t1050: ++ git -c core.compression=0 add large1 AddressSanitizer:DEADLYSIGNAL ================================================================= ==1367==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000040 (pc 0x7ffff7a01a99 bp 0x507000000db0 sp 0x7fffffff5690 T0) ==1367==The signal is caused by a READ memory access. ==1367==Hint: address points to the zero page. #0 0x7ffff7a01a99 in EVP_MD_CTX_copy_ex (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4) #1 0x555555ddde56 in openssl_SHA1_Clone ../sha1/openssl.h:40:2 #2 0x555555dce2fc in git_hash_sha1_clone_unsafe ../object-file.c:123:2 #3 0x555555c2d5f8 in hashfile_checkpoint ../csum-file.c:211:2 #4 0x555555b9905d in deflate_blob_to_pack ../bulk-checkin.c:286:4 #5 0x555555b98ae9 in index_blob_bulk_checkin ../bulk-checkin.c:362:15 #6 0x555555ddab62 in index_blob_stream ../object-file.c:2756:9 #7 0x555555dda420 in index_fd ../object-file.c:2778:9 #8 0x555555ddad76 in index_path ../object-file.c:2796:7 #9 0x555555e947f3 in add_to_index ../read-cache.c:771:7 #10 0x555555e954a4 in add_file_to_index ../read-cache.c:804:9 #11 0x5555558b5c39 in add_files ../builtin/add.c:355:7 #12 0x5555558b412e in cmd_add ../builtin/add.c:578:18 #13 0x555555b1f493 in run_builtin ../git.c:480:11 #14 0x555555b1bfef in handle_builtin ../git.c:740:9 #15 0x555555b1e6f4 in run_argv ../git.c:807:4 #16 0x555555b1b87a in cmd_main ../git.c:947:19 #17 0x5555561649e6 in main ../common-main.c:64:11 #18 0x7ffff742a1fb in __libc_start_call_main (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4) #19 0x7ffff742a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4) #20 0x555555772c84 in _start (git+0x21ec84) ==1367==Register values: rax = 0x0000511000001080 rbx = 0x0000000000000000 rcx = 0x000000000000000c rdx = 0x0000000000000000 rdi = 0x0000000000000000 rsi = 0x0000507000000db0 rbp = 0x0000507000000db0 rsp = 0x00007fffffff5690 r8 = 0x0000000000000000 r9 = 0x0000000000000000 r10 = 0x0000000000000000 r11 = 0x00007ffff7a01a30 r12 = 0x0000000000000000 r13 = 0x00007fffffff6b38 r14 = 0x00007ffff7ffd000 r15 = 0x00005555563b9910 AddressSanitizer can not provide additional info. SUMMARY: AddressSanitizer: SEGV (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4) in EVP_MD_CTX_copy_ex ==1367==ABORTING ./test-lib.sh: line 1023: 1367 Aborted git $config add large1 error: last command exited with $?=134 not ok 4 - add with -c core.compression=0 Fix the issue by using the unsafe variant instead. Signed-off-by: Patrick Steinhardt <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Dec 30, 2024
Same as with the preceding commit, git-fast-import(1) is using the safe
variant to initialize a hashfile checkpoint. This leads to a segfault
when passing the checkpoint into the hashfile subsystem because it would
use the unsafe variants instead:
++ git --git-dir=R/.git fast-import --big-file-threshold=1
AddressSanitizer:DEADLYSIGNAL
=================================================================
==577126==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000040 (pc 0x7ffff7a01a99 bp 0x5070000009c0 sp 0x7fffffff5b30 T0)
==577126==The signal is caused by a READ memory access.
==577126==Hint: address points to the zero page.
#0 0x7ffff7a01a99 in EVP_MD_CTX_copy_ex (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4)
#1 0x555555ddde56 in openssl_SHA1_Clone ../sha1/openssl.h:40:2
#2 0x555555dce2fc in git_hash_sha1_clone_unsafe ../object-file.c:123:2
#3 0x555555c2d5f8 in hashfile_checkpoint ../csum-file.c:211:2
#4 0x5555559647d1 in stream_blob ../builtin/fast-import.c:1110:2
#5 0x55555596247b in parse_and_store_blob ../builtin/fast-import.c:2031:3
#6 0x555555967f91 in file_change_m ../builtin/fast-import.c:2408:5
#7 0x55555595d8a2 in parse_new_commit ../builtin/fast-import.c:2768:4
#8 0x55555595bb7a in cmd_fast_import ../builtin/fast-import.c:3614:4
#9 0x555555b1f493 in run_builtin ../git.c:480:11
#10 0x555555b1bfef in handle_builtin ../git.c:740:9
#11 0x555555b1e6f4 in run_argv ../git.c:807:4
#12 0x555555b1b87a in cmd_main ../git.c:947:19
#13 0x5555561649e6 in main ../common-main.c:64:11
#14 0x7ffff742a1fb in __libc_start_call_main (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4)
#15 0x7ffff742a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4)
#16 0x555555772c84 in _start (git+0x21ec84)
==577126==Register values:
rax = 0x0000511000000cc0 rbx = 0x0000000000000000 rcx = 0x000000000000000c rdx = 0x0000000000000000
rdi = 0x0000000000000000 rsi = 0x00005070000009c0 rbp = 0x00005070000009c0 rsp = 0x00007fffffff5b30
r8 = 0x0000000000000000 r9 = 0x0000000000000000 r10 = 0x0000000000000000 r11 = 0x00007ffff7a01a30
r12 = 0x0000000000000000 r13 = 0x00007fffffff6b60 r14 = 0x00007ffff7ffd000 r15 = 0x00005555563b9910
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4) in EVP_MD_CTX_copy_ex
==577126==ABORTING
./test-lib.sh: line 1039: 577126 Aborted git --git-dir=R/.git fast-import --big-file-threshold=1 < input
error: last command exited with $?=134
not ok 167 - R: blob bigger than threshold
The segfault is only exposed in case the unsafe and safe backends are
different from one another.
Fix the issue by initializing the context with the unsafe SHA1 variant.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Jan 1, 2025
Our CI jobs sometimes see false positive leaks like this:
=================================================================
==3904583==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 32 byte(s) in 1 object(s) allocated from:
#0 0x7fa790d01986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
#1 0x7fa790add769 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
#2 0x7fa790d117c5 in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
#3 0x7fa790d11957 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:598
#4 0x7fa790d03fe8 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:51
#5 0x7fa790d013fd in __lsan_thread_start_func ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:440
#6 0x7fa790adc3eb in start_thread nptl/pthread_create.c:444
#7 0x7fa790b5ca5b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
This is not a leak in our code, but appears to be a race between one
thread calling exit() while another one is in LSan's stack setup code.
You can reproduce it easily by running t0003 or t5309 with --stress
(these trigger it because of the threading in git-grep and index-pack
respectively).
This may be a bug in LSan, but regardless of whether it is eventually
fixed, it is useful to work around it so that we stop seeing these false
positives.
We can recognize it by the mention of the sanitizer functions in the
DEDUP_TOKEN line. With this patch, the scripts mentioned above should
run with --stress indefinitely.
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Jan 29, 2025
When trying to create a Unix socket in a path that exceeds the maximum
socket name length we try to first change the directory into the parent
folder before creating the socket to reduce the length of the name. When
this fails we error out of `unix_sockaddr_init()` with an error code,
which indicates to the caller that the context has not been initialized.
Consequently, they don't release that context.
This leads to a memory leak: when we have already populated the context
with the original directory that we need to chdir(3p) back into, but
then the chdir(3p) into the socket's parent directory fails, then we
won't release the original directory's path. The leak is exposed by
t0301, but only via Meson with `meson setup -Dsanitize=leak`:
Direct leak of 129 byte(s) in 1 object(s) allocated from:
#0 0x5555555e85c6 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x55555590e3d6 in xrealloc ../wrapper.c:140:8
#2 0x5555558c8fc6 in strbuf_grow ../strbuf.c:114:2
#3 0x5555558cacab in strbuf_getcwd ../strbuf.c:605:3
#4 0x555555923ff6 in unix_sockaddr_init ../unix-socket.c:65:7
#5 0x555555923e42 in unix_stream_connect ../unix-socket.c:84:6
#6 0x55555562a984 in send_request ../builtin/credential-cache.c:46:11
#7 0x55555562a89e in do_cache ../builtin/credential-cache.c:108:6
#8 0x55555562a655 in cmd_credential_cache ../builtin/credential-cache.c:178:3
#9 0x555555700547 in run_builtin ../git.c:480:11
#10 0x5555556ff0e0 in handle_builtin ../git.c:740:9
#11 0x5555556ffee8 in run_argv ../git.c:807:4
#12 0x5555556fee6b in cmd_main ../git.c:947:19
#13 0x55555593f689 in main ../common-main.c:64:11
#14 0x7ffff7a2a1fb in __libc_start_call_main (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#15 0x7ffff7a2a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#16 0x5555555ad1d4 in _start (git+0x591d4)
DEDUP_TOKEN: ___interceptor_realloc.part.0--xrealloc--strbuf_grow--strbuf_getcwd--unix_sockaddr_init--unix_stream_connect--send_request--do_cache--cmd_credential_cache--run_builtin--handle_builtin--run_argv--cmd_main--main--__libc_start_call_main--__libc_start_main@GLIBC_2.2.5--_start
SUMMARY: LeakSanitizer: 129 byte(s) leaked in 1 allocation(s).
Fix this leak.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Jan 29, 2025
We don't free the result of `remote_default_branch()`, leading to a
memory leak. This leak is exposed by t9211, but only when run with Meson
via `meson setup -Dsanitize=leak`:
Direct leak of 5 byte(s) in 1 object(s) allocated from:
#0 0x5555555cfb93 in malloc (scalar+0x7bb93)
#1 0x5555556b05c2 in do_xmalloc ../wrapper.c:55:8
#2 0x5555556b06c4 in do_xmallocz ../wrapper.c:89:8
#3 0x5555556b0656 in xmallocz ../wrapper.c:97:9
#4 0x5555556b0728 in xmemdupz ../wrapper.c:113:16
#5 0x5555556b07a7 in xstrndup ../wrapper.c:119:9
#6 0x5555555d3a4b in remote_default_branch ../scalar.c:338:14
#7 0x5555555d20e6 in cmd_clone ../scalar.c:493:28
#8 0x5555555d196b in cmd_main ../scalar.c:992:14
#9 0x5555557c4059 in main ../common-main.c:64:11
#10 0x7ffff7a2a1fb in __libc_start_call_main (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#11 0x7ffff7a2a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#12 0x555555592054 in _start (scalar+0x3e054)
DEDUP_TOKEN: __interceptor_malloc--do_xmalloc--do_xmallocz--xmallocz--xmemdupz--xstrndup--remote_default_branch--cmd_clone--cmd_main--main--__libc_start_call_main--__libc_start_main@GLIBC_2.2.5--_start
SUMMARY: LeakSanitizer: 5 byte(s) leaked in 1 allocation(s).
As the `branch` variable may contain a string constant obtained from
parsing command line arguments we cannot free the leaking variable
directly. Instead, introduce a new `branch_to_free` variable that only
ever gets assigned the allocated string and free that one to plug the
leak.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Jan 30, 2025
When trying to create a Unix socket in a path that exceeds the maximum
socket name length we try to first change the directory into the parent
folder before creating the socket to reduce the length of the name. When
this fails we error out of `unix_sockaddr_init()` with an error code,
which indicates to the caller that the context has not been initialized.
Consequently, they don't release that context.
This leads to a memory leak: when we have already populated the context
with the original directory that we need to chdir(3p) back into, but
then the chdir(3p) into the socket's parent directory fails, then we
won't release the original directory's path. The leak is exposed by
t0301, but only when running tests in a directory hierarchy whose path
is long enough to make the socket name length exceed the maximum socket
name length:
Direct leak of 129 byte(s) in 1 object(s) allocated from:
#0 0x5555555e85c6 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x55555590e3d6 in xrealloc ../wrapper.c:140:8
#2 0x5555558c8fc6 in strbuf_grow ../strbuf.c:114:2
#3 0x5555558cacab in strbuf_getcwd ../strbuf.c:605:3
#4 0x555555923ff6 in unix_sockaddr_init ../unix-socket.c:65:7
#5 0x555555923e42 in unix_stream_connect ../unix-socket.c:84:6
#6 0x55555562a984 in send_request ../builtin/credential-cache.c:46:11
#7 0x55555562a89e in do_cache ../builtin/credential-cache.c:108:6
#8 0x55555562a655 in cmd_credential_cache ../builtin/credential-cache.c:178:3
#9 0x555555700547 in run_builtin ../git.c:480:11
#10 0x5555556ff0e0 in handle_builtin ../git.c:740:9
#11 0x5555556ffee8 in run_argv ../git.c:807:4
#12 0x5555556fee6b in cmd_main ../git.c:947:19
#13 0x55555593f689 in main ../common-main.c:64:11
#14 0x7ffff7a2a1fb in __libc_start_call_main (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#15 0x7ffff7a2a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#16 0x5555555ad1d4 in _start (git+0x591d4)
DEDUP_TOKEN: ___interceptor_realloc.part.0--xrealloc--strbuf_grow--strbuf_getcwd--unix_sockaddr_init--unix_stream_connect--send_request--do_cache--cmd_credential_cache--run_builtin--handle_builtin--run_argv--cmd_main--main--__libc_start_call_main--__libc_start_main@GLIBC_2.2.5--_start
SUMMARY: LeakSanitizer: 129 byte(s) leaked in 1 allocation(s).
Fix this leak.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
gitgitgadget bot
pushed a commit
that referenced
this pull request
Jan 30, 2025
We don't free the result of `remote_default_branch()`, leading to a
memory leak. This leak is exposed by t9211, but only when run with Meson
with the `-Db_sanitize=leak` option:
Direct leak of 5 byte(s) in 1 object(s) allocated from:
#0 0x5555555cfb93 in malloc (scalar+0x7bb93)
#1 0x5555556b05c2 in do_xmalloc ../wrapper.c:55:8
#2 0x5555556b06c4 in do_xmallocz ../wrapper.c:89:8
#3 0x5555556b0656 in xmallocz ../wrapper.c:97:9
#4 0x5555556b0728 in xmemdupz ../wrapper.c:113:16
#5 0x5555556b07a7 in xstrndup ../wrapper.c:119:9
#6 0x5555555d3a4b in remote_default_branch ../scalar.c:338:14
#7 0x5555555d20e6 in cmd_clone ../scalar.c:493:28
#8 0x5555555d196b in cmd_main ../scalar.c:992:14
#9 0x5555557c4059 in main ../common-main.c:64:11
#10 0x7ffff7a2a1fb in __libc_start_call_main (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#11 0x7ffff7a2a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#12 0x555555592054 in _start (scalar+0x3e054)
DEDUP_TOKEN: __interceptor_malloc--do_xmalloc--do_xmallocz--xmallocz--xmemdupz--xstrndup--remote_default_branch--cmd_clone--cmd_main--main--__libc_start_call_main--__libc_start_main@GLIBC_2.2.5--_start
SUMMARY: LeakSanitizer: 5 byte(s) leaked in 1 allocation(s).
As the `branch` variable may contain a string constant obtained from
parsing command line arguments we cannot free the leaking variable
directly. Instead, introduce a new `branch_to_free` variable that only
ever gets assigned the allocated string and free that one to plug the
leak.
It is unclear why the leak isn't flagged when running the test via our
Makefile.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
No description provided.