syzbot


KCSAN: data-race in __delete_from_page_cache / shmem_getattr

Status: auto-closed as invalid on 2021/09/27 06:47
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 471d, last: 471d

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __delete_from_page_cache / shmem_getattr

write to 0xffff88811e8aa4d0 of 8 bytes by task 12392 on cpu 0:
 page_cache_delete mm/filemap.c:145 [inline]
 __delete_from_page_cache+0x1c1/0x260 mm/filemap.c:230
 delete_from_page_cache+0x85/0x140 mm/filemap.c:265
 truncate_inode_page+0x3e/0x50 mm/truncate.c:219
 shmem_undo_range+0x210/0xe20 mm/shmem.c:927
 shmem_truncate_range mm/shmem.c:1030 [inline]
 shmem_setattr+0x375/0x450 mm/shmem.c:1091
 notify_change+0x8a3/0xa80 fs/attr.c:398
 do_truncate+0xe8/0x130 fs/open.c:64
 handle_truncate fs/namei.c:3030 [inline]
 do_open fs/namei.c:3378 [inline]
 path_openat+0x19b2/0x1f20 fs/namei.c:3507
 do_filp_open+0xe9/0x200 fs/namei.c:3534
 do_sys_openat2+0xa3/0x250 fs/open.c:1204
 do_sys_open fs/open.c:1220 [inline]
 __do_sys_openat fs/open.c:1236 [inline]
 __se_sys_openat fs/open.c:1231 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1231
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88811e8aa4d0 of 8 bytes by task 12405 on cpu 1:
 shmem_getattr+0x6e/0x250 mm/shmem.c:1043
 vfs_getattr_nosec+0x152/0x2f0 fs/stat.c:105
 vfs_getattr fs/stat.c:142 [inline]
 vfs_fstat fs/stat.c:164 [inline]
 __do_sys_newfstat fs/stat.c:404 [inline]
 __se_sys_newfstat+0x94/0x2c0 fs/stat.c:401
 __x64_sys_newfstat+0x2d/0x40 fs/stat.c:401
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000ac0 -> 0x0000000000000ab9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 12405 Comm: systemd-udevd Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/08/23 06:43 upstream 1bdc3d5be7e1 b599f2fc .config log report info KCSAN: data-race in __delete_from_page_cache / shmem_getattr
* Struck through repros no longer work on HEAD.