Syz reports: 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] __se_sys_io_uring_register+0xe4a/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 Which should be due to reading the table size after unlock. We don't care much as it's just to print it in trace, but we might as well do it under the lock. Reported-by: syzbot+5a486fef3de40e0d8c76@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- io_uring/register.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/io_uring/register.c b/io_uring/register.c index 1a60f4916649..1e99c783abdf 100644 --- a/io_uring/register.c +++ b/io_uring/register.c @@ -905,9 +905,10 @@ SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, 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->file_table.data.nr, ctx->buf_table.nr, ret); + mutex_unlock(&ctx->uring_lock); if (!use_registered_ring) fput(file); return ret; -- 2.46.0
