From b4411616c26f26c4017b8fa4d3538b1a02028733 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Wed, 13 Jan 2021 12:42:24 +0000 Subject: [PATCH] io_uring: fix null-deref in io_disable_sqo_submit 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. 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 --- fs/io_uring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index b0e6d8e607a33..66db2c46ab824 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8895,7 +8895,8 @@ 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); } /* -- 2.30.2