On Tue, Mar 21, 2023 at 3:24 PM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>
> On Tue, Mar 21, 2023 at 08:47:51AM -0700, Davidlohr Bueso wrote:
> > On Tue, 21 Mar 2023, Qiuxu Zhuo wrote:
> >
> > > When running the 'kfree_rcu_test' test case with commands [1] the call
> > > trace [2] was thrown. This was because the kfree_scale_thread thread(s)
> > > still run after unloading rcuscale and torture modules. Fix the call
> > > trace by invoking kfree_scale_cleanup() from rcu_scale_cleanup() when
> > > removing the rcuscale module.
> > >
> > > [1] modprobe rcuscale kfree_rcu_test=1
> > > // After some time
> > > rmmod rcuscale
> > > rmmod torture
> > >
> > > [2] BUG: unable to handle page fault for address: ffffffffc0601a87
> > > #PF: supervisor instruction fetch in kernel mode
> > > #PF: error_code(0x0010) - not-present page
> > > PGD 11de4f067 P4D 11de4f067 PUD 11de51067 PMD 112f4d067 PTE 0
> > > Oops: 0010 [#1] PREEMPT SMP NOPTI
> > > CPU: 1 PID: 1798 Comm: kfree_scale_thr Not tainted 6.3.0-rc1-rcu+ #1
> > > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
> > > RIP: 0010:0xffffffffc0601a87
> > > Code: Unable to access opcode bytes at 0xffffffffc0601a5d.
> > > RSP: 0018:ffffb25bc2e57e18 EFLAGS: 00010297
> > > RAX: 0000000000000000 RBX: ffffffffc061f0b6 RCX: 0000000000000000
> > > RDX: 0000000000000000 RSI: ffffffff962fd0de RDI: ffffffff962fd0de
> > > RBP: ffffb25bc2e57ea8 R08: 0000000000000000 R09: 0000000000000000
> > > R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000000
> > > R13: 0000000000000000 R14: 000000000000000a R15: 00000000001c1dbe
> > > FS: 0000000000000000(0000) GS:ffff921fa2200000(0000) knlGS:0000000000000000
> > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> > > CR2: ffffffffc0601a5d CR3: 000000011de4c006 CR4: 0000000000370ee0
> > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> > > Call Trace:
> > > <TASK>
> > > ? kvfree_call_rcu+0xf0/0x3a0
> > > ? kthread+0xf3/0x120
> > > ? kthread_complete_and_exit+0x20/0x20
> > > ? ret_from_fork+0x1f/0x30
> > > </TASK>
> > > Modules linked in: rfkill sunrpc ... [last unloaded: torture]
> > > CR2: ffffffffc0601a87
> > > ---[ end trace 0000000000000000 ]---
> > >
> > > Fixes: e6e78b004fa7 ("rcuperf: Add kfree_rcu() performance Tests")
> > > Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
> >
> > Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
>
> Much better, thank you both!
>
> But unfortunately, these patches do not apply cleanly. Qiuxu Zhuo,
> could you please forward port these to the -rcu "dev" branch [1]?
After making it cleanly apply:
Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx>
thanks,
- Joel
>
> Thanx, Paul
>
> [1] https://mirrors.edge.kernel.org/pub/linux/kernel/people/paulmck/rcutodo.html
