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]?
Thanx, Paul
[1] https://mirrors.edge.kernel.org/pub/linux/kernel/people/paulmck/rcutodo.html
