We observed panic:
BUG: kernel NULL pointer dereference, address:0000000000000028
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Oops: 0000 [#1] SMP PTI
CPU: 1 PID: 737 Comm: a.out Not tainted 5.14.0+ #58
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
RIP: 0010:vfs_fadvise+0x1e/0x80
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Call Trace:
? tctx_task_work+0x111/0x2a0
io_issue_sqe+0x524/0x1b90
This is caused by io_wq_submit_work() calling io_issue_sqe()
on a failed fadvise request, and the io_init_req() return error
before initialize the file for it, lead into the panic when
vfs_fadvise() try to access 'req->file'.
This patch add the missing check & handle for failed request
before calling io_issue_sqe().
Signed-off-by: Michael Wang <yun.wang@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 6f35b12..bfec7bf 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2214,7 +2214,8 @@ static void io_req_task_submit(struct io_kiocb *req, bool *locked)
io_tw_lock(ctx, locked);
/* req->task == current here, checking PF_EXITING is safe */
- if (likely(!(req->task->flags & PF_EXITING)))
+ if (likely(!(req->task->flags & PF_EXITING) &&
+ !(req->flags & REQ_F_FAIL)))
__io_queue_sqe(req);
else
io_req_complete_failed(req, -EFAULT);
@@ -6704,7 +6705,10 @@ static void io_wq_submit_work(struct io_wq_work *work)
if (!ret) {
do {
- ret = io_issue_sqe(req, 0);
+ if (likely(!(req->flags & REQ_F_FAIL)))
+ ret = io_issue_sqe(req, 0);
+ else
+ io_req_complete_failed(req, -EFAULT);
/*
* We can get EAGAIN for polled IO even though we're
* forcing a sync submission from here, since we can't
--
1.8.3.1
