diff mbox series

[RESEND] riscv: stacktrace: Fix NULL pointer dereference

Message ID 20210716214051.32eea3a8@xhacker (mailing list archive)
State New, archived
Headers show
Series [RESEND] riscv: stacktrace: Fix NULL pointer dereference | expand

Commit Message

Jisheng Zhang July 16, 2021, 1:40 p.m. UTC 
From: Jisheng Zhang <jszhang@kernel.org>

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>
---
 arch/riscv/kernel/stacktrace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Atish Patra July 16, 2021, 2:07 p.m. UTC | #1 
On Fri, Jul 16, 2021 at 6:47 AM Jisheng Zhang <jszhang3@mail.ustc.edu.cn> wrote:
>
> From: Jisheng Zhang <jszhang@kernel.org>
>
> 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>
> ---
>  arch/riscv/kernel/stacktrace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index bde85fc53357..7bc8af75933a 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);
> --
> 2.32.0
>
>
>
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv


Reviewed-by: Atish Patra <atish.patra@wdc.com>
twd2 July 21, 2021, 8:25 a.m. UTC | #2 
Tested-by: Wende Tan <twd2.me@gmail.com>


On 2021/7/16 21:40, Jisheng Zhang wrote:
> From: Jisheng Zhang <jszhang@kernel.org>
>
> 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>
> ---
>  arch/riscv/kernel/stacktrace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> index bde85fc53357..7bc8af75933a 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);

Thanks.
Wende
Jisheng Zhang July 24, 2021, 4:02 p.m. UTC | #3 
Hi @Palmer,

On Fri, 16 Jul 2021 07:07:24 -0700
Atish Patra <atishp@atishpatra.org> wrote:

> On Fri, Jul 16, 2021 at 6:47 AM Jisheng Zhang wrote:
> >
> > From: Jisheng Zhang <jszhang@kernel.org>
> >
> > 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"

Missed a ")" at the end here, do you want a resend?

PS: This patch is missed for twice.

Thanks

> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
> > ---
> >  arch/riscv/kernel/stacktrace.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
> > index bde85fc53357..7bc8af75933a 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);
> > --
> > 2.32.0
> >
> >
> >
> > _______________________________________________
> > linux-riscv mailing list
> > linux-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-riscv  
> 
> 
> Reviewed-by: Atish Patra <atish.patra@wdc.com>
>
Palmer Dabbelt July 24, 2021, 8:15 p.m. UTC | #4 
On Sat, 24 Jul 2021 09:02:58 PDT (-0700), jszhang3@mail.ustc.edu.cn wrote:
> Hi @Palmer,
>
> On Fri, 16 Jul 2021 07:07:24 -0700
> Atish Patra <atishp@atishpatra.org> wrote:
>
>> On Fri, Jul 16, 2021 at 6:47 AM Jisheng Zhang wrote:
>> >
>> > From: Jisheng Zhang <jszhang@kernel.org>
>> >
>> > 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"
>
> Missed a ")" at the end here, do you want a resend?
>
> PS: This patch is missed for twice.

Sorry about that.   I remember having seen this, so I'm not sure what 
happened.  It's on fixes now, but I'm just sending up a PR so this will 
go up in the next one.

>
> Thanks
>
>> > Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
>> > ---
>> >  arch/riscv/kernel/stacktrace.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
>> > index bde85fc53357..7bc8af75933a 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);
>> > --
>> > 2.32.0
>> >
>> >
>> >
>> > _______________________________________________
>> > linux-riscv mailing list
>> > linux-riscv@lists.infradead.org
>> > http://lists.infradead.org/mailman/listinfo/linux-riscv
>>
>>
>> Reviewed-by: Atish Patra <atish.patra@wdc.com>
>>
diff mbox series

Patch

diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index bde85fc53357..7bc8af75933a 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);