From: Pavel Begunkov Date: Tue, 26 Jan 2021 11:17:04 +0000 (+0000) Subject: io_uring: fix null-deref in io_disable_sqo_submit X-Git-Tag: rel_imx_5.10.35_2.0.0-somdevices.0~363^2~2072 X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=0e3562e3b2aeb4a6aa4615185a8f59c51cade61b;p=linux.git io_uring: fix null-deref in io_disable_sqo_submit [ Upstream commit b4411616c26f26c4017b8fa4d3538b1a02028733 ] general protection fault, probably for non-canonical address 0xdffffc0000000022: 0000 [#1] KASAN: null-ptr-deref in range [0x0000000000000110-0x0000000000000117] RIP: 0010:io_ring_set_wakeup_flag fs/io_uring.c:6929 [inline] RIP: 0010:io_disable_sqo_submit+0xdb/0x130 fs/io_uring.c:8891 Call Trace: io_uring_create fs/io_uring.c:9711 [inline] io_uring_setup+0x12b1/0x38e0 fs/io_uring.c:9739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 io_disable_sqo_submit() might be called before user rings were allocated, don't do io_ring_set_wakeup_flag() in those cases. Cc: stable@vger.kernel.org # 5.5+ Reported-by: syzbot+ab412638aeb652ded540@syzkaller.appspotmail.com Fixes: d9d05217cb69 ("io_uring: stop SQPOLL submit on creator's death") Signed-off-by: Pavel Begunkov Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- diff --git a/fs/io_uring.c b/fs/io_uring.c index bcc26fc04d00..239cbcf439a2 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8757,7 +8757,8 @@ static void io_disable_sqo_submit(struct io_ring_ctx *ctx) mutex_unlock(&ctx->uring_lock); /* make sure callers enter the ring to get error */ - io_ring_set_wakeup_flag(ctx); + if (ctx->rings) + io_ring_set_wakeup_flag(ctx); } /*