diff options
| author | Jisheng Zhang <jszhang@kernel.org> | 2021-07-23 03:22:26 +0300 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-07-24 03:29:03 +0300 |
| commit | 76f5dfacfb42b75e5782c017827877cfcee20474 (patch) | |
| tree | 1c207942448c8806d386abbaa606ac15615d831f | |
| parent | db6b84a368b495cb7e41be9cb9e73d4d0537d027 (diff) | |
| download | linux-76f5dfacfb42b75e5782c017827877cfcee20474.tar.xz | |
riscv: stacktrace: pin the task's stack in get_wchan
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>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
| -rw-r--r-- | arch/riscv/kernel/stacktrace.c | 6 |
1 files changed, 5 insertions, 1 deletions
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; } |