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KCSAN: data-race in smc_switch_to_fallback / sock_poll

Status: auto-obsoleted due to no activity on 2025/11/05 02:09
Subsystems: smc
[Documentation on labels]
First crash: 88d, last: 88d

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

write to 0xffff88811385db58 of 8 bytes by task 9288 on cpu 0:
 smc_switch_to_fallback+0x508/0x800 net/smc/af_smc.c:934
 smc_sendmsg+0xce/0x2f0 net/smc/af_smc.c:2800
 sock_sendmsg_nosec net/socket.c:714 [inline]
 __sock_sendmsg+0x142/0x180 net/socket.c:729
 __sys_sendto+0x268/0x330 net/socket.c:2228
 __do_sys_sendto net/socket.c:2235 [inline]
 __se_sys_sendto net/socket.c:2231 [inline]
 __x64_sys_sendto+0x76/0x90 net/socket.c:2231
 x64_sys_call+0x2d05/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:45
 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 0xffff88811385db58 of 8 bytes by task 9285 on cpu 1:
 sock_poll+0x27/0x240 net/socket.c:1411
 vfs_poll include/linux/poll.h:82 [inline]
 __io_arm_poll_handler+0x1ee/0xb70 io_uring/poll.c:581
 io_poll_add+0x69/0xe0 io_uring/poll.c:901
 __io_issue_sqe+0xfe/0x2e0 io_uring/io_uring.c:1773
 io_issue_sqe+0x53/0x970 io_uring/io_uring.c:1796
 io_queue_sqe io_uring/io_uring.c:2025 [inline]
 io_submit_sqe io_uring/io_uring.c:2285 [inline]
 io_submit_sqes+0x675/0x1060 io_uring/io_uring.c:2398
 __do_sys_io_uring_enter io_uring/io_uring.c:3465 [inline]
 __se_sys_io_uring_enter+0x1c1/0x1b70 io_uring/io_uring.c:3399
 __x64_sys_io_uring_enter+0x78/0x90 io_uring/io_uring.c:3399
 x64_sys_call+0x2de1/0x2ff0 arch/x86/include/generated/asm/syscalls_64.h:427
 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: 0xffff88810559a700 -> 0xffff88810559b0c0

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9285 Comm: syz.9.13932 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/10 02:06 upstream 9dd1835ecda5 fdeaa69b .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in smc_switch_to_fallback / sock_poll
* Struck through repros no longer work on HEAD.