syzbot


KCSAN: data-race in copy_creds / prepare_creds (2)

Status: moderation: reported on 2025/12/01 07:50
Subsystems: lsm
[Documentation on labels]
Reported-by: syzbot+a9c18b3cb9f026e801ba@syzkaller.appspotmail.com
First crash: 105d, last: 18d
✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
320db6a4-5932-4a57-b5ff-55bfa3073d72 repro 💥 KCSAN: data-race in copy_creds / prepare_creds (2) 2026/03/10 12:29 2026/03/10 12:29 2026/03/10 12:29 5c03941b7fba0fd3b0326afc981322c89fe9ba52+ failed to run ["git" "pull" "origin" "HEAD" "--depth=1" "--allow-unrelated-histories"]: exit status 1
77707e63-582f-4e2c-8461-b3be63b11a0d assessment-kcsan Benign: ✅  Confident: ✅  KCSAN: data-race in copy_creds / prepare_creds (2) 2026/01/14 17:36 2026/01/14 17:36 2026/01/14 17:41 a9d6a79219801d2130df3b1a792c57f0e5428e9f
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in copy_creds / prepare_creds lsm 6 3 164d 182d 0/29 auto-obsoleted due to no activity on 2025/11/29 06:24

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

write to 0xffff888103e1f8e8 of 4 bytes by task 13803 on cpu 0:
 get_cred_many include/linux/cred.h:218 [inline]
 copy_creds+0x78/0x340 kernel/cred.c:278
 copy_process+0x62f/0x20d0 kernel/fork.c:2084
 kernel_clone+0x16b/0x5d0 kernel/fork.c:2654
 __do_sys_clone3 kernel/fork.c:2956 [inline]
 __se_sys_clone3+0x1f5/0x230 kernel/fork.c:2935
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:2935
 x64_sys_call+0x580/0x3020 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103e1f840 of 184 bytes by task 13812 on cpu 1:
 prepare_creds+0x6d/0x540 kernel/cred.c:192
 __do_sys_capset kernel/capability.c:247 [inline]
 __se_sys_capset+0x2da/0x480 kernel/capability.c:216
 __x64_sys_capset+0x31/0x40 kernel/capability.c:216
 x64_sys_call+0x2aac/0x3020 arch/x86/include/generated/asm/syscalls_64.h:127
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x370 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 13812 Comm: syz.7.2682 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
==================================================================

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/02/26 09:49 upstream d9d32e5bd5a4 e0f78d93 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
2026/01/29 22:04 upstream 8dfce8991b95 aeb6fdd5 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
2026/01/07 02:50 upstream f0b9d8eb98df d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
2026/01/02 13:47 upstream b69053dd3ffb d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
2025/12/15 22:44 upstream 8f0b4cce4481 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
2025/12/01 07:50 upstream 7d0a66e4bb90 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_creds / prepare_creds
* Struck through repros no longer work on HEAD.