On 11/13/24 11:08, syzbot wrote:
Hello, syzbot found the following issue on: HEAD commit: 2d5404caa8c7 Linux 6.12-rc7 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=10e838c0580000 kernel config: https://syzkaller.appspot.com/x/.config?x=29fedde79f609854 dashboard link: https://syzkaller.appspot.com/bug?extid=5a486fef3de40e0d8c76 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/15a7713979b8/disk-2d5404ca.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/b51c4f695d4a/vmlinux-2d5404ca.xz kernel image: https://storage.googleapis.com/syzbot-assets/e8c0f17bc00b/bzImage-2d5404ca.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+5a486fef3de40e0d8c76@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KCSAN: data-race in __se_sys_io_uring_register / io_sqe_files_register read-write to 0xffff8881021940b8 of 4 bytes by task 5923 on cpu 1: io_sqe_files_register+0x2c4/0x3b0 io_uring/rsrc.c:713 __io_uring_register io_uring/register.c:403 [inline] __do_sys_io_uring_register io_uring/register.c:611 [inline] __se_sys_io_uring_register+0x8d0/0x1280 io_uring/register.c:591 __x64_sys_io_uring_register+0x55/0x70 io_uring/register.c:591 x64_sys_call+0x202/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:428 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff8881021940b8 of 4 bytes by task 5924 on cpu 0: __do_sys_io_uring_register io_uring/register.c:613 [inline]
Seems to point to tracing: mutex_lock(&ctx->uring_lock); ret = __io_uring_register(ctx, opcode, arg, nr_args); mutex_unlock(&ctx->uring_lock); trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret); And thus we don't care much about it, but we can just move it one line up under the lock. -- Pavel Begunkov
