---------- Forwarded message --------- From: Changhui Zhong <czhong@xxxxxxxxxx> Date: Mon, Jun 23, 2025 at 4:48 PM Subject: Re: [bug report] BUG: kernel NULL pointer dereference, address: 0000000000000001 To: Ming Lei <ming.lei@xxxxxxxxxx> On Mon, Jun 23, 2025 at 12:02 PM Ming Lei <ming.lei@xxxxxxxxxx> wrote: > > Hi Changhui, > > On Mon, Jun 23, 2025 at 10:58:24AM +0800, Changhui Zhong wrote: > > Hello, > > > > the following kernel panic was triggered by ubdsrv generic/002, > > please help check and let me know if you need any info/test, thanks. > > > > commit HEAD: > > > > commit 2589cd05008205ee29f5f66f24a684732ee2e3a3 > > Merge: 98d0347fe8fb e1c75831f682 > > Author: Jens Axboe <axboe@xxxxxxxxx> > > Date: Wed Jun 18 05:11:50 2025 -0600 > > > > Merge branch 'io_uring-6.16' into for-next > > > > * io_uring-6.16: > > io_uring: fix potential page leak in io_sqe_buffer_register() > > io_uring/sqpoll: don't put task_struct on tctx setup failure > > io_uring: remove duplicate io_uring_alloc_task_context() definition > > The above branch has been merged to v6.16-rc3, can you reproduce it with -rc3? > > I tried to duplicate in my test VM, not succeed with -rc3. > Hi，Ming I hit this issue with repo https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/log/?h=for-next. it is not a 100% reproducible issue. I triggered it in the run T=generic as loop, ‘for i in {0..10};do make test T=generic; done’ and later I tried it with repo https://github.com/torvalds/linux, branch v6.16-rc3, but have not been able to reproduce it so far. > ... > > > [ 7044.064528] BUG: kernel NULL pointer dereference, address: 0000000000000001 > > [ 7044.071507] #PF: supervisor read access in kernel mode > > [ 7044.076653] #PF: error_code(0x0000) - not-present page > > [ 7044.081801] PGD 462c42067 P4D 462c42067 PUD 462c43067 PMD 0 > > [ 7044.087488] Oops: Oops: 0000 [#1] SMP NOPTI > > [ 7044.091685] CPU: 13 UID: 0 PID: 367 Comm: kworker/13:1H Not tainted > > 6.16.0-rc2+ #1 PREEMPT(voluntary) > > [ 7044.100991] Hardware name: Dell Inc. PowerEdge R640/0X45NX, BIOS > > 2.22.2 09/12/2024 > > [ 7044.108565] Workqueue: kblockd blk_mq_requeue_work > > [ 7044.113374] RIP: 0010:__io_req_task_work_add+0x18/0x1f0 > > Can you share where the above line points to source line if it can be > reproduced in -rc3? > > gdb> l *(__io_req_task_work_add+0x18) > > vmlinux is compiled by repo https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git ，branch for-next， (gdb) l *(__io_req_task_work_add+0x18) 0xffffffff819075e8 is in __io_req_task_work_add (io_uring/io_uring.c:1251). 1246 io_fallback_tw(tctx, false); 1247 } 1248 1249 void __io_req_task_work_add(struct io_kiocb *req, unsigned flags) 1250 { 1251 if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) 1252 io_req_local_work_add(req, flags); 1253 else 1254 io_req_normal_work_add(req); 1255 } (gdb) > Thanks, > Ming > Thanks， Changhui
