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KCSAN: data-race in step_into / vfs_unlink

Status: closed as invalid on 2020/06/18 14:24
Subsystems: fs
[Documentation on labels]
First crash: 1430d, last: 1381d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in step_into / vfs_unlink (2) fs 1081 722d 1334d 0/26 auto-closed as invalid on 2022/05/11 15:48

Sample crash report:
==================================================================
BUG: KCSAN: data-race in step_into / vfs_unlink

write to 0xffff8880b6dfa780 of 4 bytes by task 14297 on cpu 0:
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_unlink+0x267/0x400 fs/namei.c:3811
 do_unlinkat+0x33f/0x550 fs/namei.c:3873
 __do_sys_unlink fs/namei.c:3920 [inline]
 __se_sys_unlink fs/namei.c:3918 [inline]
 __x64_sys_unlink+0x38/0x50 fs/namei.c:3918
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b6dfa780 of 4 bytes by task 5284 on cpu 1:
 d_is_symlink include/linux/dcache.h:419 [inline]
 step_into+0xea/0x1090 fs/namei.c:1680
 walk_component+0xde/0x390 fs/namei.c:1852
 lookup_last fs/namei.c:2295 [inline]
 path_lookupat.isra.0+0x119/0x350 fs/namei.c:2319
 filename_lookup+0x145/0x2c0 fs/namei.c:2352
 user_path_at_empty+0x47/0x60 fs/namei.c:2632
 do_readlinkat+0x89/0x230 fs/stat.c:409
 __do_sys_readlink fs/stat.c:442 [inline]
 __se_sys_readlink fs/stat.c:439 [inline]
 __x64_sys_readlink+0x4c/0x60 fs/stat.c:439
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5284 Comm: systemd-udevd Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/06/16 09:19 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 baca2611 .config console log report ci2-upstream-kcsan-gce
2020/06/12 14:32 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 819b58b0 .config console log report ci2-upstream-kcsan-gce
2020/06/11 15:00 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 3ab7a05a .config console log report ci2-upstream-kcsan-gce
2020/06/10 19:54 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 5caaad3a .config console log report ci2-upstream-kcsan-gce
2020/06/09 04:02 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 0d60b78a .config console log report ci2-upstream-kcsan-gce
2020/06/01 02:11 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 a0331e89 .config console log report ci2-upstream-kcsan-gce
2020/05/21 10:46 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 4afdfa20 .config console log report ci2-upstream-kcsan-gce
2020/05/10 21:01 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 8742a2b9 .config console log report ci2-upstream-kcsan-gce
2020/05/05 08:19 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 9941337c .config console log report ci2-upstream-kcsan-gce
2020/05/04 13:51 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 58ae5e18 .config console log report ci2-upstream-kcsan-gce
2020/04/28 11:18 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 e3ecea2e .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.