syzbot


KCSAN: data-race in do_readlinkat / vfs_unlink

Status: closed as invalid on 2019/10/18 14:11
Subsystems: fs
[Documentation on labels]
First crash: 1653d, last: 1653d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_readlinkat / vfs_unlink (2) fs 383 1051d 1456d 0/26 auto-closed as invalid on 2021/07/07 20:42

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

write to 0xffff888122c05540 of 4 bytes by task 7406 on cpu 0:
 dont_mount include/linux/dcache.h:352 [inline]
 vfs_unlink+0x26a/0x3e0 fs/namei.c:4001
 do_unlinkat+0x32b/0x530 fs/namei.c:4063
 __do_sys_unlink fs/namei.c:4110 [inline]
 __se_sys_unlink fs/namei.c:4108 [inline]
 __x64_sys_unlink+0x3b/0x50 fs/namei.c:4108
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888122c05540 of 4 bytes by task 3905 on cpu 1:
 d_is_symlink include/linux/dcache.h:419 [inline]
 do_readlinkat+0xda/0x220 fs/stat.c:407
 __do_sys_readlink fs/stat.c:432 [inline]
 __se_sys_readlink fs/stat.c:429 [inline]
 __x64_sys_readlink+0x51/0x70 fs/stat.c:429
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3905 Comm: udevd Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 3905 Comm: udevd Not tainted 5.3.0+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0xf5/0x159 lib/dump_stack.c:113
 panic+0x209/0x639 kernel/panic.c:219
 kcsan_report.cold+0xc/0x1b kernel/kcsan/report.c:303
 __kcsan_setup_watchpoint+0x3ee/0x510 kernel/kcsan/core.c:455
 __tsan_read4 kernel/kcsan/kcsan.c:30 [inline]
 __tsan_read4+0x2c/0x30 kernel/kcsan/kcsan.c:30
 d_is_symlink include/linux/dcache.h:419 [inline]
 do_readlinkat+0xda/0x220 fs/stat.c:407
 __do_sys_readlink fs/stat.c:432 [inline]
 __se_sys_readlink fs/stat.c:429 [inline]
 __x64_sys_readlink+0x51/0x70 fs/stat.c:429
 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f5c418fb577
Code: f0 ff ff 77 02 f3 c3 48 8b 15 bd 38 2b 00 f7 d8 64 89 02 83 c8 ff c3 90 90 90 90 90 90 90 90 90 90 90 90 b8 59 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 38 2b 00 31 d2 48 29 c2 64
RSP: 002b:00007ffc22f3fe28 EFLAGS: 00000206 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00000000009b0250 RCX: 00007f5c418fb577
RDX: 00000000000003fc RSI: 00007ffc22f40254 RDI: 00007ffc22f3fe50
RBP: 00000000000003fc R08: 00000000009b00d0 R09: 00007f5c419501d0
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000003
R13: 0000000000000000 R14: 00000000009c27b0 R15: 00000000009b0250
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/10/09 19:41 https://github.com/google/ktsan.git kcsan d724f94f63de c4b9981b .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.