syzbot


KCSAN: data-race in do_settimeofday64 / ktime_get_real_seconds

Status: closed as invalid on 2020/06/18 14:13
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 796d, last: 796d
similar bugs (3):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_settimeofday64 / ktime_get_real_seconds (4) 34 299d 497d 0/23 auto-closed as invalid on 2021/11/18 03:13
upstream KCSAN: data-race in do_settimeofday64 / ktime_get_real_seconds (3) 4 555d 584d 0/23 auto-closed as invalid on 2021/03/06 23:28
upstream KCSAN: data-race in do_settimeofday64 / ktime_get_real_seconds (2) 15 620d 609d 0/23 auto-closed as invalid on 2021/01/01 01:41

Sample crash report:
==================================================================
BUG: KCSAN: data-race in do_settimeofday64 / ktime_get_real_seconds

write to 0xffffffff88ae9138 of 8 bytes by task 26302 on cpu 1:
 tk_set_xtime kernel/time/timekeeping.c:118 [inline]
 do_settimeofday64 kernel/time/timekeeping.c:1249 [inline]
 do_settimeofday64+0x251/0x3b0 kernel/time/timekeeping.c:1223
 do_sys_settimeofday64 kernel/time/time.c:195 [inline]
 do_sys_settimeofday64+0x172/0x1b0 kernel/time/time.c:169
 posix_clock_realtime_set+0x1e/0x30 kernel/time/posix-timers.c:185
 __do_sys_clock_settime kernel/time/posix-timers.c:1079 [inline]
 __se_sys_clock_settime kernel/time/posix-timers.c:1067 [inline]
 __x64_sys_clock_settime+0xee/0x170 kernel/time/posix-timers.c:1067
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff88ae9138 of 8 bytes by task 26303 on cpu 0:
 ktime_get_real_seconds+0x1d/0x30 kernel/time/timekeeping.c:127
 recently_deleted fs/ext4/ialloc.c:699 [inline]
 find_inode_bit.isra.0+0x1e7/0x330 fs/ext4/ialloc.c:724
 __ext4_new_inode+0xd7b/0x3020 fs/ext4/ialloc.c:927
 ext4_symlink+0x322/0x9e0 fs/ext4/namei.c:3295
 vfs_symlink fs/namei.c:3937 [inline]
 vfs_symlink+0x216/0x330 fs/namei.c:3923
 do_symlinkat+0x1ac/0x1e0 fs/namei.c:3964
 __do_sys_symlink fs/namei.c:3983 [inline]
 __se_sys_symlink fs/namei.c:3981 [inline]
 __x64_sys_symlink+0x3c/0x50 fs/namei.c:3981
 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: 0 PID: 26303 Comm: syz-executor.2 Not tainted 5.7.0-rc1-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 2020/06/03 13:31 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 a5ce5de0 .config log report