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KCSAN: data-race in search_nested_keyrings / search_nested_keyrings (4)

Status: moderation: reported on 2025/11/28 06:41
Subsystems: keyrings lsm
[Documentation on labels]
Reported-by: syzbot+fba113b7915d88a69ecb@syzkaller.appspotmail.com
First crash: 60d, last: 36d
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in search_nested_keyrings / search_nested_keyrings (2) lsm keyrings 6 1 647d 647d 0/29 auto-obsoleted due to no activity on 2024/05/25 15:41
upstream KCSAN: data-race in search_nested_keyrings / search_nested_keyrings (3) keyrings lsm 6 1 139d 139d 0/29 auto-obsoleted due to no activity on 2025/11/05 05:48
upstream KCSAN: data-race in search_nested_keyrings / search_nested_keyrings lsm keyrings 6 3 2266d 2277d 0/29 auto-closed as invalid on 2020/01/23 16:46

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

write to 0xffff8881001a3560 of 8 bytes by task 23290 on cpu 0:
 search_nested_keyrings+0x7ac/0x9b0 security/keys/keyring.c:860
 keyring_search_rcu+0xf7/0x190 security/keys/keyring.c:925
 get_user_session_keyring_rcu security/keys/process_keys.c:208 [inline]
 search_cred_keyrings_rcu+0x2a3/0x3c0 security/keys/process_keys.c:500
 search_process_keyrings_rcu security/keys/process_keys.c:544 [inline]
 lookup_user_key+0x8eb/0xd10 security/keys/process_keys.c:762
 keyctl_keyring_unlink+0x23/0x120 security/keys/keyctl.c:558
 __do_sys_keyctl security/keys/keyctl.c:1906 [inline]
 __se_sys_keyctl+0x5a3/0xb80 security/keys/keyctl.c:1874
 __x64_sys_keyctl+0x67/0x80 security/keys/keyctl.c:1874
 x64_sys_call+0x27b8/0x3000 arch/x86/include/generated/asm/syscalls_64.h:251
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

write to 0xffff8881001a3560 of 8 bytes by task 23291 on cpu 1:
 search_nested_keyrings+0x7ac/0x9b0 security/keys/keyring.c:860
 keyring_search_rcu+0xf7/0x190 security/keys/keyring.c:925
 get_user_session_keyring_rcu security/keys/process_keys.c:208 [inline]
 search_cred_keyrings_rcu+0x2a3/0x3c0 security/keys/process_keys.c:500
 search_process_keyrings_rcu security/keys/process_keys.c:544 [inline]
 lookup_user_key+0x8eb/0xd10 security/keys/process_keys.c:762
 keyctl_pkey_params_get+0x25b/0x320 security/keys/keyctl_pkey.c:98
 keyctl_pkey_query+0x58/0x1b0 security/keys/keyctl_pkey.c:177
 __do_sys_keyctl security/keys/keyctl.c:1990 [inline]
 __se_sys_keyctl+0x7ed/0xb80 security/keys/keyctl.c:1874
 __x64_sys_keyctl+0x67/0x80 security/keys/keyctl.c:1874
 x64_sys_call+0x27b8/0x3000 arch/x86/include/generated/asm/syscalls_64.h:251
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xca/0x2b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000001b3 -> 0x00000000000001b5

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 23291 Comm: syz.1.6511 Tainted: G        W           syzkaller #0 PREEMPT(voluntary) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/22 21:51 upstream 9448598b22c5 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in search_nested_keyrings / search_nested_keyrings
2025/11/28 06:40 upstream e1afacb68573 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in search_nested_keyrings / search_nested_keyrings
* Struck through repros no longer work on HEAD.