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| author | Jisheng Zhang <jszhang@kernel.org> | 2021-07-16 15:40:51 +0200 |
|---|---|---|
| committer | Palmer Dabbelt <palmerdabbelt@google.com> | 2021-07-24 21:58:51 +0200 |
| commit | 78d9d8005e4556448f398d876f29d0ca7ab8e398 (patch) | |
| tree | 4782fdee278ec857dec07dcdb3e76095a3d463c4 /arch | |
| parent | riscv: __asm_copy_to-from_user: Fix: Typos in comments (diff) | |
| download | linux-78d9d8005e4556448f398d876f29d0ca7ab8e398.tar.xz linux-78d9d8005e4556448f398d876f29d0ca7ab8e398.zip | |
riscv: stacktrace: Fix NULL pointer dereference
When CONFIG_FRAME_POINTER=y, calling dump_stack() can always trigger
NULL pointer dereference panic similar as below:
[ 0.396060] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc5+ #47
[ 0.396692] Hardware name: riscv-virtio,qemu (DT)
[ 0.397176] Call Trace:
[ 0.398191] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000960
[ 0.399487] Oops [#1]
[ 0.399739] Modules linked in:
[ 0.400135] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc5+ #47
[ 0.400570] Hardware name: riscv-virtio,qemu (DT)
[ 0.400926] epc : walk_stackframe+0xc4/0xdc
[ 0.401291] ra : dump_backtrace+0x30/0x38
[ 0.401630] epc : ffffffff80004922 ra : ffffffff8000496a sp : ffffffe000f3bd00
[ 0.402115] gp : ffffffff80cfdcb8 tp : ffffffe000f30000 t0 : ffffffff80d0b0cf
[ 0.402602] t1 : ffffffff80d0b0c0 t2 : 0000000000000000 s0 : ffffffe000f3bd60
[ 0.403071] s1 : ffffffff808bc2e8 a0 : 0000000000001000 a1 : 0000000000000000
[ 0.403448] a2 : ffffffff803d7088 a3 : ffffffff808bc2e8 a4 : 6131725dbc24d400
[ 0.403820] a5 : 0000000000001000 a6 : 0000000000000002 a7 : ffffffffffffffff
[ 0.404226] s2 : 0000000000000000 s3 : 0000000000000000 s4 : 0000000000000000
[ 0.404634] s5 : ffffffff803d7088 s6 : ffffffff808bc2e8 s7 : ffffffff80630650
[ 0.405085] s8 : ffffffff80912a80 s9 : 0000000000000008 s10: ffffffff804000fc
[ 0.405388] s11: 0000000000000000 t3 : 0000000000000043 t4 : ffffffffffffffff
[ 0.405616] t5 : 000000000000003d t6 : ffffffe000f3baa8
[ 0.405793] status: 0000000000000100 badaddr: 0000000000000960 cause: 000000000000000d
[ 0.406135] [<ffffffff80004922>] walk_stackframe+0xc4/0xdc
[ 0.407032] [<ffffffff8000496a>] dump_backtrace+0x30/0x38
[ 0.407797] [<ffffffff803d7100>] show_stack+0x40/0x4c
[ 0.408234] [<ffffffff803d9e5c>] dump_stack+0x90/0xb6
[ 0.409019] [<ffffffff8040423e>] ptdump_init+0x20/0xc4
[ 0.409681] [<ffffffff800015b6>] do_one_initcall+0x4c/0x226
[ 0.410110] [<ffffffff80401094>] kernel_init_freeable+0x1f4/0x258
[ 0.410562] [<ffffffff803dba88>] kernel_init+0x22/0x148
[ 0.410959] [<ffffffff800029e2>] ret_from_exception+0x0/0x14
[ 0.412241] ---[ end trace b2ab92c901b96251 ]---
[ 0.413099] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
The reason is the task is NULL when we finally call walk_stackframe()
the NULL is passed from __dump_stack():
|static void __dump_stack(void)
|{
| dump_stack_print_info(KERN_DEFAULT);
| show_stack(NULL, NULL, KERN_DEFAULT);
|}
Fix this issue by checking "task == NULL" case in walk_stackframe().
Fixes: eac2f3059e02 ("riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabled")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Tested-by: Wende Tan <twd2.me@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/kernel/stacktrace.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index ac7593607fa6..315db3d0229b 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -27,7 +27,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, fp = frame_pointer(regs); sp = user_stack_pointer(regs); pc = instruction_pointer(regs); - } else if (task == current) { + } else if (task == NULL || task == current) { fp = (unsigned long)__builtin_frame_address(1); sp = (unsigned long)__builtin_frame_address(0); pc = (unsigned long)__builtin_return_address(0); |