From: Jisheng Zhang <jszhang3@mail.ustc.edu.cn>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>
Cc: linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
Andreas Schwab <schwab@linux-m68k.org>,
Atish Patra <atishp@atishpatra.org>
Subject: [PATCH] riscv: stacktrace: pin the task's stack in get_wchan
Date: Fri, 23 Jul 2021 08:22:26 +0800 [thread overview]
Message-ID: <20210723082226.7b7b4707@xhacker> (raw)
From: Jisheng Zhang <jszhang@kernel.org>
Pin the task's stack before calling walk_stackframe() in get_wchan().
This can fix the panic as reported by Andreas when CONFIG_VMAP_STACK=y:
[ 65.609696] Unable to handle kernel paging request at virtual address ffffffd0003bbde8
[ 65.610460] Oops [#1]
[ 65.610626] Modules linked in: virtio_blk virtio_mmio rtc_goldfish btrfs blake2b_generic libcrc32c xor raid6_pq sg dm_multipath dm_mod scsi_dh_rdac scsi_dh_emc scsi_dh_alua efivarfs
[ 65.611670] CPU: 2 PID: 1 Comm: systemd Not tainted 5.14.0-rc1-1.g34fe32a-default #1 openSUSE Tumbleweed (unreleased) c62f7109153e5a0897ee58ba52393ad99b070fd2
[ 65.612334] Hardware name: riscv-virtio,qemu (DT)
[ 65.613008] epc : get_wchan+0x5c/0x88
[ 65.613334] ra : get_wchan+0x42/0x88
[ 65.613625] epc : ffffffff800048a4 ra : ffffffff8000488a sp : ffffffd00021bb90
[ 65.614008] gp : ffffffff817709f8 tp : ffffffe07fe91b80 t0 : 00000000000001f8
[ 65.614411] t1 : 0000000000020000 t2 : 0000000000000000 s0 : ffffffd00021bbd0
[ 65.614818] s1 : ffffffd0003bbdf0 a0 : 0000000000000001 a1 : 0000000000000002
[ 65.615237] a2 : ffffffff81618008 a3 : 0000000000000000 a4 : 0000000000000000
[ 65.615637] a5 : ffffffd0003bc000 a6 : 0000000000000002 a7 : ffffffe27d370000
[ 65.616022] s2 : ffffffd0003bbd90 s3 : ffffffff8071a81e s4 : 0000000000003fff
[ 65.616407] s5 : ffffffffffffc000 s6 : 0000000000000000 s7 : ffffffff81618008
[ 65.616845] s8 : 0000000000000001 s9 : 0000000180000040 s10: 0000000000000000
[ 65.617248] s11: 000000000000016b t3 : 000000ff00000000 t4 : 0c6aec92de5e3fd7
[ 65.617672] t5 : fff78f60608fcfff t6 : 0000000000000078
[ 65.618088] status: 0000000000000120 badaddr: ffffffd0003bbde8 cause: 000000000000000d
[ 65.618621] [<ffffffff800048a4>] get_wchan+0x5c/0x88
[ 65.619008] [<ffffffff8022da88>] do_task_stat+0x7a2/0xa46
[ 65.619325] [<ffffffff8022e87e>] proc_tgid_stat+0xe/0x16
[ 65.619637] [<ffffffff80227dd6>] proc_single_show+0x46/0x96
[ 65.619979] [<ffffffff801ccb1e>] seq_read_iter+0x190/0x31e
[ 65.620341] [<ffffffff801ccd70>] seq_read+0xc4/0x104
[ 65.620633] [<ffffffff801a6bfe>] vfs_read+0x6a/0x112
[ 65.620922] [<ffffffff801a701c>] ksys_read+0x54/0xbe
[ 65.621206] [<ffffffff801a7094>] sys_read+0xe/0x16
[ 65.621474] [<ffffffff8000303e>] ret_from_syscall+0x0/0x2
[ 65.622169] ---[ end trace f24856ed2b8789c5 ]---
[ 65.622832] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/kernel/stacktrace.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index ff467b98c3e3..ac7593607fa6 100644
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -132,8 +132,12 @@ unsigned long get_wchan(struct task_struct *task)
{
unsigned long pc = 0;
- if (likely(task && task != current && !task_is_running(task)))
+ if (likely(task && task != current && !task_is_running(task))) {
+ if (!try_get_task_stack(task))
+ return 0;
walk_stackframe(task, NULL, save_wchan, &pc);
+ put_task_stack(task);
+ }
return pc;
}
--
2.32.0
next reply other threads:[~2021-07-23 0:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-23 0:22 Jisheng Zhang [this message]
2021-07-24 0:58 ` [PATCH] riscv: stacktrace: pin the task's stack in get_wchan Palmer Dabbelt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210723082226.7b7b4707@xhacker \
--to=jszhang3@mail.ustc.edu.cn \
--cc=aou@eecs.berkeley.edu \
--cc=atishp@atishpatra.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
--cc=schwab@linux-m68k.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).