| Message ID | 20210723082226.7b7b4707@xhacker (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: stacktrace: pin the task's stack in get_wchan | expand |
On Thu, 22 Jul 2021 17:22:26 PDT (-0700), jszhang3@mail.ustc.edu.cn wrote: > 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; > } Thanks, this is on fixes.
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; }