From: Pengfei Xu <pengfei.xu@intel.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Pavel Begunkov <asml.silence@gmail.com>,
<linux-kernel@vger.kernel.org>, <heng.su@intel.com>
Subject: Re: [Syzkaller & bisect] There is "io_ring_exit_work" related Call Trace in v5.2-rc5 kernel
Date: Fri, 3 Feb 2023 10:08:16 +0800 [thread overview]
Message-ID: <Y9xskCrKaTGZptRw@xpf.sh.intel.com> (raw)
In-Reply-To: <affab34f-2b83-9158-5976-b224a4afce0d@kernel.dk>
Hi Jens Axboe,
On 2023-02-02 at 13:37:43 -0700, Jens Axboe wrote:
> On 2/2/23 12:44?PM, Jens Axboe wrote:
> > On 2/2/23 1:56?AM, Pengfei Xu wrote:
> >> Hi Pavel Begunkov,
> >>
> >> On 2023-02-01 at 15:52:47 +0000, Pavel Begunkov wrote:
> >>> On 1/28/23 14:49, Pavel Begunkov wrote:
> >>>> On 1/28/23 08:44, Pengfei Xu wrote:
> >>>>> Hi Pavel Begunkov and kernel expert,
> >>>>>
> >>>>> Greeting!
> >>>>>
> >>>>> There is "io_ring_exit_work" related Call Trace in v5.2-rc5 kernel in guest
> >>>>> on Sapphire Rapids server.
> >>>>
> >>>> Thanks for the report, we'll take a look
> >>>
> >>> Not reproducible for me. Apparently, the repro creates a normal ring
> >>> and immediately closes it, then io_ring_exit_work() hangs waiting to
> >>> the task to execute task_work.
> >> Ah, I put the reproduced virtual machine in gitlab.
> >> git clone https://gitlab.com/xupengfe/repro_vm_env.git
> >> cd repro_vm_env
> >> tar -xvf repro_vm_env.tar.gz
> >> cd repro_vm_env; ./start3.sh // it needs qemu-system-x86_64 and I used v7.1.0
> >> //start3.sh will load bzImage_2241ab53cbb5cdb08a6b2d4688feb13971058f65 v6.2-rc5 kernel
> >> In vm and login with root, there is no password for root.
> >> After login vm successfully, ./repro to reproduce this issue.
> >> It could be reproduced in about 6min.
> >>
> >> If you already have qemu-system-x86_64, please ignore below info.
> >> If you want to install qemu v7.1.0 version,
> >> git clone https://github.com/qemu/qemu.git
> >> cd qemu
> >> git checkout -f v7.1.0
> >> mkdir build
> >> cd build
> >> yum install -y ninja-build.x86_64
> >> ../configure --target-list=x86_64-softmmu --enable-kvm --enable-vnc --enable-gtk --enable-sdl
> >> make
> >> make install
> >> Done.
> >
> > Are you sure you attached the right kconfig in the initial report? It
> > is from 5.18.x.
Yes, the kconfig from initial report is first used by 5.18.x kernel,
and I added some new kconfig item based on the kconfig like kernel ibt:
CONFIG_X86_KERNEL_IBT=y and so on.
And use the kconfig then "make olddefconfig" to generate the kconfig
for latest kernel.
I will add above vm environment and kconfig making info for reproduced
steps if I find new kernel issues.
Thanks for remind!
>
> Looks like a bug in 9p, can you try this?
Thanks for your patch!
The following patch was installed on top of v6.2-rc5 kernel, and tested this
issue in vm on SPR and RPL-S platforms(reproduced platforms as before).
This issue could not be reproduced in 40 min.
Test result shows that this patch solves the problem.
Thanks!
BR.
>
>
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 622ec6a586ee..5756d812d3d4 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -18,6 +18,7 @@
> #include <linux/sched/signal.h>
> #include <linux/uaccess.h>
> #include <linux/uio.h>
> +#include <linux/task_work.h>
> #include <net/9p/9p.h>
> #include <linux/parser.h>
> #include <linux/seq_file.h>
> @@ -652,6 +653,24 @@ static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
> return ERR_PTR(err);
> }
>
> +static int p9_sigpending(void)
> +{
> + int sigpending = 0;
> +
> + if (signal_pending(current)) {
> + if (test_thread_flag(TIF_NOTIFY_SIGNAL))
> + clear_notify_signal();
> + if (task_work_pending(current))
> + task_work_run();
> + if (signal_pending(current)) {
> + sigpending = 1;
> + clear_thread_flag(TIF_SIGPENDING);
> + }
> + }
> +
> + return sigpending;
> +}
> +
> /**
> * p9_client_rpc - issue a request and wait for a response
> * @c: client session
> @@ -687,12 +706,7 @@ p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
> req->tc.zc = false;
> req->rc.zc = false;
>
> - if (signal_pending(current)) {
> - sigpending = 1;
> - clear_thread_flag(TIF_SIGPENDING);
> - } else {
> - sigpending = 0;
> - }
> + sigpending = p9_sigpending();
>
> err = c->trans_mod->request(c, req);
> if (err < 0) {
> @@ -789,12 +803,7 @@ static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
> req->tc.zc = true;
> req->rc.zc = true;
>
> - if (signal_pending(current)) {
> - sigpending = 1;
> - clear_thread_flag(TIF_SIGPENDING);
> - } else {
> - sigpending = 0;
> - }
> + sigpending = p9_sigpending();
>
> err = c->trans_mod->zc_request(c, req, uidata, uodata,
> inlen, olen, in_hdrlen);
>
> --
> Jens Axboe
>
prev parent reply other threads:[~2023-02-03 2:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-28 8:44 [Syzkaller & bisect] There is "io_ring_exit_work" related Call Trace in v5.2-rc5 kernel Pengfei Xu
2023-01-28 8:52 ` [Syzkaller & bisect] There is "io_ring_exit_work" related Call Trace in v6.2-rc5 kernel Pengfei Xu
2023-01-28 14:49 ` [Syzkaller & bisect] There is "io_ring_exit_work" related Call Trace in v5.2-rc5 kernel Pavel Begunkov
2023-02-01 15:52 ` Pavel Begunkov
2023-02-02 8:56 ` Pengfei Xu
2023-02-02 19:44 ` Jens Axboe
2023-02-02 20:37 ` Jens Axboe
2023-02-03 2:08 ` Pengfei Xu [this message]
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