abaci reported the follow issue: RDX: 0000000000000001 RSI: 0000000020000a80 RDI: 0000000000007a32 RBP: 0000000000000000 R08: 00007facc4ccb1bd R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004007c0 R13: 00007ffdf5fa1380 R14: 0000000000000000 R15: 0000000000000000 BUG: kernel NULL pointer dereference, address: 00000000000000c0 PGD 8000000105fc7067 P4D 8000000105fc7067 PUD 10c6a5067 PMD 0 Oops: 0002 [#1] SMP PTI Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:io_commit_cqring+0xf6/0x190 fs/io_uring.c:1318 Code: 85 c0 0f 85 6d ff ff ff e8 67 2d d4 ff 44 89 a5 10 06 00 00 e8 5b 2d d4 ff 48 8b 85 40 04 00 00 8b 95 00 06 00 00 4c 8d 65 78 <89> 90 c0 00 00 00 48 8b 45 78 49 39 c4 75 6c 5b 5d 41 5c 41 5d e9 RSP: 0018:ffffc90001283db0 EFLAGS: 00010093 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff814c2b45 RDI: ffff888105f0b000 RBP: ffff888105f0b000 R08: ffff88810c534c80 R09: 00000000fffffffe R10: 0000000089b853a8 R11: 00000000fec8d1bc R12: ffff888105f0b078 R13: ffff888105f0b088 R14: 0000000000000000 R15: 0000000000100140 FS: 00007facc547d740(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000000000c0 CR3: 000000010c5a0006 CR4: 00000000003706e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: io_kill_timeouts+0x125/0x140 fs/io_uring.c:8606 io_ring_ctx_wait_and_kill+0x109/0x1d0 fs/io_uring.c:8629 io_uring_create+0x4c9/0xfb0 fs/io_uring.c:9574 io_uring_setup+0x8c/0xd0 fs/io_uring.c:9601 do_syscall_64+0x2d/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7facc4d76239 Code: 01 00 48 81 c4 80 00 00 00 e9 f1 fe ff ff 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 27 ec 2c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffdf5fa1298 EFLAGS: 00000246 ORIG_RAX: 00000000000001a9 RAX: ffffffffffffffda RBX: 0000000000400d38 RCX: 00007facc4d76239 RDX: 0000000000000001 RSI: 0000000020000a80 RDI: 0000000000007a32 RBP: 0000000000000000 R08: 00007facc4ccb1bd R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004007c0 R13: 00007ffdf5fa1380 R14: 0000000000000000 R15: 0000000000000000 Modules linked in: Dumping ftrace buffer: (ftrace buffer empty) CR2: 00000000000000c0 This is caused by access ctx->rings in io_ring_ctx_wait_and_kill() while ctx->rings is NULL because of allocation failure. Reported-by: Abaci <abaci@xxxxxxxxxxxxxxxxx> Signed-off-by: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 1949b80677e7..03f593f5e740 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -8616,12 +8616,16 @@ static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) unsigned long index; struct creds *creds; + if (!ctx->rings) { + io_ring_ctx_free(ctx); + return; + } + mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); /* if force is set, the ring is going away. always drop after that */ ctx->cq_overflow_flushed = 1; - if (ctx->rings) - __io_cqring_overflow_flush(ctx, true, NULL, NULL); + __io_cqring_overflow_flush(ctx, true, NULL, NULL); xa_for_each(&ctx->personalities, index, creds) io_unregister_personality(ctx, index); mutex_unlock(&ctx->uring_lock); -- 1.8.3.1