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KCSAN: data-race in ktime_get_real_seconds / timekeeping_inject_offset

Status: auto-closed as invalid on 2020/08/23 09:27
Subsystems: kernel
[Documentation on labels]
First crash: 1848d, last: 1823d
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in ktime_get_real_seconds / timekeeping_inject_offset (2) kernel 6 94 1373d 1682d 0/29 auto-closed as invalid on 2021/11/16 23:32

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

write to 0xffffffff892c3df8 of 8 bytes by task 26528 on cpu 1:
 tk_xtime_add kernel/time/timekeeping.c:124 [inline]
 timekeeping_inject_offset+0x453/0x6d0 kernel/time/timekeeping.c:1295
 do_adjtimex+0x57e/0x670 kernel/time/timekeeping.c:2332
 posix_clock_realtime_adj+0x11/0x20 kernel/time/posix-timers.c:191
 do_clock_adjtime kernel/time/posix-timers.c:1109 [inline]
 __do_sys_clock_adjtime kernel/time/posix-timers.c:1121 [inline]
 __se_sys_clock_adjtime kernel/time/posix-timers.c:1112 [inline]
 __x64_sys_clock_adjtime+0x12c/0x1b0 kernel/time/posix-timers.c:1112
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff892c3df8 of 8 bytes by task 26529 on cpu 0:
 ktime_get_real_seconds+0x11/0x20 kernel/time/timekeeping.c:939
 recently_deleted fs/ext4/ialloc.c:699 [inline]
 find_inode_bit+0x231/0x3a0 fs/ext4/ialloc.c:724
 __ext4_new_inode+0xc84/0x2fc0 fs/ext4/ialloc.c:927
 ext4_symlink+0x354/0x7e0 fs/ext4/namei.c:3303
 vfs_symlink+0x218/0x2f0 fs/namei.c:3953
 do_symlinkat+0xee/0x280 fs/namei.c:3980
 __do_sys_symlink fs/namei.c:3999 [inline]
 __se_sys_symlink fs/namei.c:3997 [inline]
 __x64_sys_symlink+0x32/0x40 fs/namei.c:3997
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 26529 Comm: syz-executor.2 Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/07/19 09:25 upstream f932d58abc38 9c812472 .config console log report ci2-upstream-kcsan-gce
2020/07/16 09:50 upstream 994e99a96c9b ada108d0 .config console log report ci2-upstream-kcsan-gce
2020/06/24 15:38 upstream 3e08a95294a4 41694dbf .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.