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KCSAN: data-race in avc_policy_seqno / avc_ss_reset (3)

Status: moderation: reported on 2025/04/03 01:45
Subsystems: selinux
[Documentation on labels]
Reported-by: syzbot+a7f7cb0737bd91aa698c@syzkaller.appspotmail.com
First crash: 151d, last: 6d21h
Similar bugs (2)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in avc_policy_seqno / avc_ss_reset selinux 6 1 371d 371d 0/29 auto-obsoleted due to no activity on 2024/09/30 10:46
upstream KCSAN: data-race in avc_policy_seqno / avc_ss_reset (2) selinux 6 6 227d 284d 0/29 auto-obsoleted due to no activity on 2025/03/14 17:24

Sample crash report:
==================================================================
BUG: KCSAN: data-race in avc_policy_seqno / avc_ss_reset

write to 0xffffffff88e82ce8 of 4 bytes by task 16786 on cpu 1:
 avc_latest_notif_update security/selinux/avc.c:582 [inline]
 avc_ss_reset+0x20c/0x240 security/selinux/avc.c:971
 selinux_notify_policy_change security/selinux/ss/services.c:2231 [inline]
 security_set_bools+0x301/0x340 security/selinux/ss/services.c:3166
 sel_commit_bools_write+0x1ea/0x270 security/selinux/selinuxfs.c:1333
 do_loop_readv_writev fs/read_write.c:850 [inline]
 vfs_writev+0x406/0x8b0 fs/read_write.c:1059
 do_writev+0xe7/0x210 fs/read_write.c:1103
 __do_sys_writev fs/read_write.c:1171 [inline]
 __se_sys_writev fs/read_write.c:1168 [inline]
 __x64_sys_writev+0x45/0x50 fs/read_write.c:1168
 x64_sys_call+0x1e9a/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:21
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffffffff88e82ce8 of 4 bytes by task 13460 on cpu 0:
 avc_policy_seqno+0x15/0x30 security/selinux/avc.c:1207
 selinux_file_open+0x10e/0x330 security/selinux/hooks.c:4132
 security_file_open+0x36/0x70 security/security.c:3144
 do_dentry_open+0x204/0xa20 fs/open.c:942
 vfs_open+0x37/0x1e0 fs/open.c:1095
 do_open fs/namei.c:3887 [inline]
 path_openat+0x1c5e/0x2170 fs/namei.c:4046
 do_filp_open+0x109/0x230 fs/namei.c:4073
 do_sys_openat2+0xa6/0x110 fs/open.c:1435
 do_sys_open fs/open.c:1450 [inline]
 __do_sys_openat fs/open.c:1466 [inline]
 __se_sys_openat fs/open.c:1461 [inline]
 __x64_sys_openat+0xf2/0x120 fs/open.c:1461
 x64_sys_call+0x2e9c/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:258
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000007 -> 0x00000008

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 13460 Comm: syz-executor Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (20):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/26 00:44 upstream b6add54ba618 bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/08/19 10:42 upstream be48bcf004f9 523f460e .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/08/14 18:01 upstream 0cc53520e68b 5d8c2ac2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/08/13 11:50 upstream 8742b2d8935f 22ec1469 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/08/09 08:51 upstream 2988dfed8a5d 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/08/05 02:53 upstream d632ab86aff2 f5bcc8dc .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/08/01 19:52 upstream f2d282e1dfb3 40127d41 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/07/29 20:03 upstream 0919a5b3b11c f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/07/24 18:16 upstream 25fae0b93d1d 65d60d73 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/07/15 20:04 upstream 155a3c003e55 03fcfc4b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/07/13 04:58 upstream 3f31a806a62e 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/07/07 03:01 upstream d7b8f8e20813 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/06/28 13:03 upstream 67a993863163 fc9d8ee5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/06/17 18:06 upstream 9afe652958c3 cfebc887 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/06/13 20:59 upstream 02adc1490e6d 98683f8f .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/06/06 05:31 upstream e271ed52b344 6b6b5f21 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/05/29 03:57 upstream 3d413f0cfd7e 3d2f584d .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/05/22 07:26 upstream d608703fcdd9 0919b50b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/05/16 05:43 upstream fee3e843b309 cfde8269 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
2025/04/03 01:44 upstream 92b71befc349 c799dfdd .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in avc_policy_seqno / avc_ss_reset
* Struck through repros no longer work on HEAD.