[syzbot] [perf?] KCSAN: data-race in __perf_event_overflow / __perf_event_set_bpf_prog (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0ce37745d4bf Merge tag 'block-7.2-20260724' of git://git.k..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1410388e580000
kernel config: https://syzkaller.appspot.com/x/.config?x=84b3039e8461eef5
dashboard link: https://syzkaller.appspot.com/bug?extid=d2b7abb7919cbc9a984f
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/82454ebb316b/disk-0ce37745.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/728ae5f54b86/vmlinux-0ce37745.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4ce26f3067dd/bzImage-0ce37745.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d2b7ab...@syzkaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in __perf_event_overflow / __perf_event_set_bpf_prog

write to 0xffff88811ac6a2a8 of 8 bytes by task 23981 on cpu 0:
perf_event_set_bpf_handler kernel/events/core.c:10711 [inline]
__perf_event_set_bpf_prog+0x46b/0x4d0 kernel/events/core.c:11697
_perf_ioctl kernel/events/core.c:6662 [inline]
perf_ioctl+0x8e4/0x1590 kernel/events/core.c:6722
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xce/0x140 fs/ioctl.c:583
__x64_sys_ioctl+0x43/0x50 fs/ioctl.c:583
x64_sys_call+0x1563/0x3020 arch/x86/include/generated/asm/syscalls_64.h:17
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88811ac6a2a8 of 8 bytes by interrupt on cpu 1:
__perf_event_overflow+0x230/0x940 kernel/events/core.c:10769
perf_event_overflow kernel/events/core.c:10853 [inline]
perf_swevent_hrtimer+0x28d/0x310 kernel/events/core.c:12273
__run_hrtimer kernel/time/hrtimer.c:2032 [inline]
__hrtimer_run_queues+0x1f8/0x510 kernel/time/hrtimer.c:2096
hrtimer_interrupt+0x257/0x810 kernel/time/hrtimer.c:2215
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline]
__sysvec_apic_timer_interrupt+0x5f/0x1c0 arch/x86/kernel/apic/apic.c:1068
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline]
sysvec_apic_timer_interrupt+0x6f/0x80 arch/x86/kernel/apic/apic.c:1062
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
__sanitizer_cov_trace_pc+0x8/0x70 kernel/kcov.c:213
chacha_permute+0x39a/0x510 lib/crypto/chacha-block-generic.c:24
chacha_block_generic+0x47/0x310 lib/crypto/chacha-block-generic.c:83
chacha20_block include/crypto/chacha.h:45 [inline]
get_random_bytes_user+0xf7/0x2b0 drivers/char/random.c:458
__do_sys_getrandom drivers/char/random.c:1406 [inline]
__se_sys_getrandom drivers/char/random.c:1380 [inline]
__x64_sys_getrandom+0xcf/0x1a0 drivers/char/random.c:1380
x64_sys_call+0x2a28/0x3020 arch/x86/include/generated/asm/syscalls_64.h:319
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffffc9000511d000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 23978 Comm: syz.3.7094 Tainted: G W syzkaller #0 PREEMPT(lazy)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
==================================================================


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