On 9/1/21 10:39 AM, 王贇 wrote: > We observed panic: > BUG: kernel NULL pointer dereference, address:0000000000000028 > [skip] > 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 > [skip] > Call Trace: > ? tctx_task_work+0x111/0x2a0 > io_issue_sqe+0x524/0x1b90 Most likely it was fixed yesterday. Can you try? https://git.kernel.dk/cgit/linux-block/log/?h=for-5.15/io_uring Or these two patches in particular https://git.kernel.dk/cgit/linux-block/commit/?h=for-5.15/io_uring&id=c6d3d9cbd659de8f2176b4e4721149c88ac096d4 https://git.kernel.dk/cgit/linux-block/commit/?h=for-5.15/io_uring&id=b8ce1b9d25ccf81e1bbabd45b963ed98b2222df8 > 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 > -- Pavel Begunkov
