| Message ID | 20210627092659.46193-1-changbin.du@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | riscv: stacktrace: fix dump_backtrace/walk_stackframe with NULL task | expand |
On Sun, 27 Jun 2021 17:26:59 +0800 Changbin Du <changbin.du@gmail.com> wrote: > > > Some places try to show backtrace with NULL task, and expect the task is > 'current'. For example, dump_stack()->show_stack(NULL,...). So the > stacktrace code should take care of this case. I fixed this issue one week ago: http://lists.infradead.org/pipermail/linux-riscv/2021-June/007258.html > > Here is an oops caused by this issue when accessing the NULL task. > > [ 15.180813] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. > [ 15.182382] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc7-00111-g625acffd7ae2-dirty #18 > [ 15.183431] Hardware name: riscv-virtio,qemu (DT) > [ 15.184253] Call Trace: > [ 15.223617] Unable to handle kernel paging request at virtual address 0000000000001590 > [ 15.267378] Oops [#1] > [ 15.268215] Modules linked in: > [ 15.272027] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc7-00111-g625acffd7ae2-dirty #18 > [ 15.273997] Hardware name: riscv-virtio,qemu (DT) > [ 15.275134] epc : walk_stackframe+0xc4/0xdc > [ 15.280146] ra : dump_backtrace+0x30/0x38 > [ 15.280799] epc : ffffffff8000597e ra : ffffffff800059c6 sp : ffffffe002383d60 > [ 15.281622] gp : ffffffff8179ad18 tp : ffffffe002378000 t0 : ffffffff81bc1a3f > [ 15.282574] t1 : 0000000000000001 t2 : 0000000000000000 s0 : ffffffe002383dc0 > [ 15.283782] s1 : ffffffff812b7d18 a0 : 0000000000001000 a1 : 0000000000000000 > [ 15.285115] a2 : ffffffff807ec668 a3 : ffffffff812b7d18 a4 : c76c00cabf08b500 > [ 15.286213] a5 : 0000000000001000 a6 : 000000001a9ef260 a7 : 0000000000000000 > [ 15.287317] s2 : 0000000000000000 s3 : 0000000000000000 s4 : 0000000000000000 > [ 15.288323] s5 : ffffffff807ec668 s6 : ffffffff812b7d18 s7 : 0000000000000000 > [ 15.289530] s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000000000000000 > [ 15.290995] s11: 0000000000000000 t3 : 0000000000000001 t4 : 0000000000000000 > [ 15.292465] t5 : 206f74206e6f6974 t6 : ffffffe002383b28 > [ 15.293859] status: 0000000000000100 badaddr: 0000000000001590 cause: 000000000000000d > [ 15.296035] [<ffffffff8000597e>] walk_stackframe+0xc4/0xdc > [ 15.297342] [<ffffffff800059c6>] dump_backtrace+0x30/0x38 > [ 15.298333] [<ffffffff807ec6e0>] show_stack+0x40/0x4c > [ 15.299765] [<ffffffff807f07ac>] dump_stack+0x7c/0x96 > [ 15.300553] [<ffffffff807ec8be>] panic+0x118/0x300 > [ 15.301147] [<ffffffff807f61e8>] kernel_init+0x12c/0x138 > [ 15.302056] [<ffffffff80003a22>] ret_from_exception+0x0/0xc > [ 15.338628] ---[ end trace 0a3fa0cc7f3393cd ]--- > [ 15.339919] note: swapper/0[1] exited with preempt_count 1 > [ 15.341995] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > [ 15.343889] SMP: stopping secondary CPUs > [ 16.802836] SMP: failed to stop secondary CPUs 0-3 > [ 16.806264] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- > > This patch fixes it by setting the task to current if it's NULL before > accessing it. > > Signed-off-by: Changbin Du <changbin.du@gmail.com> > Fixes: 5d8544e2d0 ("RISC-V: Generic library routines and assembly") Hmm, this fixes tag should be Fixes: eac2f3059e02 ("riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabled" > --- > arch/riscv/kernel/stacktrace.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c > index bde85fc53357..788b65eba965 100644 > --- a/arch/riscv/kernel/stacktrace.c > +++ b/arch/riscv/kernel/stacktrace.c > @@ -23,6 +23,9 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, > { > unsigned long fp, sp, pc; > > + if (!task) > + task = current; > + > if (regs) { > fp = frame_pointer(regs); > sp = user_stack_pointer(regs); > @@ -73,6 +76,9 @@ void notrace walk_stackframe(struct task_struct *task, > unsigned long sp, pc; > unsigned long *ksp; > > + if (!task) > + task = current; > + > if (regs) { > sp = user_stack_pointer(regs); > pc = instruction_pointer(regs); > -- > 2.30.2 > > > _______________________________________________ > linux-riscv mailing list > linux-riscv@lists.infradead.org
On Mon, Jun 28, 2021 at 01:44:04PM +0800, Jisheng Zhang wrote: > On Sun, 27 Jun 2021 17:26:59 +0800 > Changbin Du <changbin.du@gmail.com> wrote: > > > > > > > > Some places try to show backtrace with NULL task, and expect the task is > > 'current'. For example, dump_stack()->show_stack(NULL,...). So the > > stacktrace code should take care of this case. > > I fixed this issue one week ago: > > http://lists.infradead.org/pipermail/linux-riscv/2021-June/007258.html > Good to know. Thanks! > > > > Here is an oops caused by this issue when accessing the NULL task. > > > > [ 15.180813] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. > > [ 15.182382] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc7-00111-g625acffd7ae2-dirty #18 > > [ 15.183431] Hardware name: riscv-virtio,qemu (DT) > > [ 15.184253] Call Trace: > > [ 15.223617] Unable to handle kernel paging request at virtual address 0000000000001590 > > [ 15.267378] Oops [#1] > > [ 15.268215] Modules linked in: > > [ 15.272027] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc7-00111-g625acffd7ae2-dirty #18 > > [ 15.273997] Hardware name: riscv-virtio,qemu (DT) > > [ 15.275134] epc : walk_stackframe+0xc4/0xdc > > [ 15.280146] ra : dump_backtrace+0x30/0x38 > > [ 15.280799] epc : ffffffff8000597e ra : ffffffff800059c6 sp : ffffffe002383d60 > > [ 15.281622] gp : ffffffff8179ad18 tp : ffffffe002378000 t0 : ffffffff81bc1a3f > > [ 15.282574] t1 : 0000000000000001 t2 : 0000000000000000 s0 : ffffffe002383dc0 > > [ 15.283782] s1 : ffffffff812b7d18 a0 : 0000000000001000 a1 : 0000000000000000 > > [ 15.285115] a2 : ffffffff807ec668 a3 : ffffffff812b7d18 a4 : c76c00cabf08b500 > > [ 15.286213] a5 : 0000000000001000 a6 : 000000001a9ef260 a7 : 0000000000000000 > > [ 15.287317] s2 : 0000000000000000 s3 : 0000000000000000 s4 : 0000000000000000 > > [ 15.288323] s5 : ffffffff807ec668 s6 : ffffffff812b7d18 s7 : 0000000000000000 > > [ 15.289530] s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000000000000000 > > [ 15.290995] s11: 0000000000000000 t3 : 0000000000000001 t4 : 0000000000000000 > > [ 15.292465] t5 : 206f74206e6f6974 t6 : ffffffe002383b28 > > [ 15.293859] status: 0000000000000100 badaddr: 0000000000001590 cause: 000000000000000d > > [ 15.296035] [<ffffffff8000597e>] walk_stackframe+0xc4/0xdc > > [ 15.297342] [<ffffffff800059c6>] dump_backtrace+0x30/0x38 > > [ 15.298333] [<ffffffff807ec6e0>] show_stack+0x40/0x4c > > [ 15.299765] [<ffffffff807f07ac>] dump_stack+0x7c/0x96 > > [ 15.300553] [<ffffffff807ec8be>] panic+0x118/0x300 > > [ 15.301147] [<ffffffff807f61e8>] kernel_init+0x12c/0x138 > > [ 15.302056] [<ffffffff80003a22>] ret_from_exception+0x0/0xc > > [ 15.338628] ---[ end trace 0a3fa0cc7f3393cd ]--- > > [ 15.339919] note: swapper/0[1] exited with preempt_count 1 > > [ 15.341995] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > > [ 15.343889] SMP: stopping secondary CPUs > > [ 16.802836] SMP: failed to stop secondary CPUs 0-3 > > [ 16.806264] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- > > > > This patch fixes it by setting the task to current if it's NULL before > > accessing it. > > > > Signed-off-by: Changbin Du <changbin.du@gmail.com> > > Fixes: 5d8544e2d0 ("RISC-V: Generic library routines and assembly") > > Hmm, this fixes tag should be > Fixes: eac2f3059e02 ("riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabled" > > > > --- > > arch/riscv/kernel/stacktrace.c | 6 ++++++ > > 1 file changed, 6 insertions(+) > > > > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c > > index bde85fc53357..788b65eba965 100644 > > --- a/arch/riscv/kernel/stacktrace.c > > +++ b/arch/riscv/kernel/stacktrace.c > > @@ -23,6 +23,9 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, > > { > > unsigned long fp, sp, pc; > > > > + if (!task) > > + task = current; > > + > > if (regs) { > > fp = frame_pointer(regs); > > sp = user_stack_pointer(regs); > > @@ -73,6 +76,9 @@ void notrace walk_stackframe(struct task_struct *task, > > unsigned long sp, pc; > > unsigned long *ksp; > > > > + if (!task) > > + task = current; > > + > > if (regs) { > > sp = user_stack_pointer(regs); > > pc = instruction_pointer(regs); > > -- > > 2.30.2 > > > > > > _______________________________________________ > > linux-riscv mailing list > > linux-riscv@lists.infradead.org >
On Mon, Jun 28, 2021 at 01:44:04PM +0800, Jisheng Zhang wrote: > On Sun, 27 Jun 2021 17:26:59 +0800 > Changbin Du <changbin.du@gmail.com> wrote: > > > > > > > > Some places try to show backtrace with NULL task, and expect the task is > > 'current'. For example, dump_stack()->show_stack(NULL,...). So the > > stacktrace code should take care of this case. > > I fixed this issue one week ago: > > http://lists.infradead.org/pipermail/linux-riscv/2021-June/007258.html I still see this issue on mainline. Is your fix merged? Thanks!
On Wed, 28 Jul 2021 06:16:56 +0800 Changbin Du <changbin.du@gmail.com> wrote: > On Mon, Jun 28, 2021 at 01:44:04PM +0800, Jisheng Zhang wrote: > > On Sun, 27 Jun 2021 17:26:59 +0800 > > Changbin Du <changbin.du@gmail.com> wrote: > > > > > > > > > > > > > Some places try to show backtrace with NULL task, and expect the task is > > > 'current'. For example, dump_stack()->show_stack(NULL,...). So the > > > stacktrace code should take care of this case. > > > > I fixed this issue one week ago: > > > > http://lists.infradead.org/pipermail/linux-riscv/2021-June/007258.html > > I still see this issue on mainline. Is your fix merged? Thanks! Nope, the fix is missed twice. Palmer has added the fix patch into fix branch, I help it will be in next rc Regards
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index bde85fc53357..788b65eba965 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -23,6 +23,9 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs, { unsigned long fp, sp, pc; + if (!task) + task = current; + if (regs) { fp = frame_pointer(regs); sp = user_stack_pointer(regs); @@ -73,6 +76,9 @@ void notrace walk_stackframe(struct task_struct *task, unsigned long sp, pc; unsigned long *ksp; + if (!task) + task = current; + if (regs) { sp = user_stack_pointer(regs); pc = instruction_pointer(regs);
Some places try to show backtrace with NULL task, and expect the task is 'current'. For example, dump_stack()->show_stack(NULL,...). So the stacktrace code should take care of this case. Here is an oops caused by this issue when accessing the NULL task. [ 15.180813] Kernel panic - not syncing: No working init found. Try passing init= option to kernel. See Linux Documentation/admin-guide/init.rst for guidance. [ 15.182382] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc7-00111-g625acffd7ae2-dirty #18 [ 15.183431] Hardware name: riscv-virtio,qemu (DT) [ 15.184253] Call Trace: [ 15.223617] Unable to handle kernel paging request at virtual address 0000000000001590 [ 15.267378] Oops [#1] [ 15.268215] Modules linked in: [ 15.272027] CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.13.0-rc7-00111-g625acffd7ae2-dirty #18 [ 15.273997] Hardware name: riscv-virtio,qemu (DT) [ 15.275134] epc : walk_stackframe+0xc4/0xdc [ 15.280146] ra : dump_backtrace+0x30/0x38 [ 15.280799] epc : ffffffff8000597e ra : ffffffff800059c6 sp : ffffffe002383d60 [ 15.281622] gp : ffffffff8179ad18 tp : ffffffe002378000 t0 : ffffffff81bc1a3f [ 15.282574] t1 : 0000000000000001 t2 : 0000000000000000 s0 : ffffffe002383dc0 [ 15.283782] s1 : ffffffff812b7d18 a0 : 0000000000001000 a1 : 0000000000000000 [ 15.285115] a2 : ffffffff807ec668 a3 : ffffffff812b7d18 a4 : c76c00cabf08b500 [ 15.286213] a5 : 0000000000001000 a6 : 000000001a9ef260 a7 : 0000000000000000 [ 15.287317] s2 : 0000000000000000 s3 : 0000000000000000 s4 : 0000000000000000 [ 15.288323] s5 : ffffffff807ec668 s6 : ffffffff812b7d18 s7 : 0000000000000000 [ 15.289530] s8 : 0000000000000000 s9 : 0000000000000000 s10: 0000000000000000 [ 15.290995] s11: 0000000000000000 t3 : 0000000000000001 t4 : 0000000000000000 [ 15.292465] t5 : 206f74206e6f6974 t6 : ffffffe002383b28 [ 15.293859] status: 0000000000000100 badaddr: 0000000000001590 cause: 000000000000000d [ 15.296035] [<ffffffff8000597e>] walk_stackframe+0xc4/0xdc [ 15.297342] [<ffffffff800059c6>] dump_backtrace+0x30/0x38 [ 15.298333] [<ffffffff807ec6e0>] show_stack+0x40/0x4c [ 15.299765] [<ffffffff807f07ac>] dump_stack+0x7c/0x96 [ 15.300553] [<ffffffff807ec8be>] panic+0x118/0x300 [ 15.301147] [<ffffffff807f61e8>] kernel_init+0x12c/0x138 [ 15.302056] [<ffffffff80003a22>] ret_from_exception+0x0/0xc [ 15.338628] ---[ end trace 0a3fa0cc7f3393cd ]--- [ 15.339919] note: swapper/0[1] exited with preempt_count 1 [ 15.341995] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 15.343889] SMP: stopping secondary CPUs [ 16.802836] SMP: failed to stop secondary CPUs 0-3 [ 16.806264] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- This patch fixes it by setting the task to current if it's NULL before accessing it. Signed-off-by: Changbin Du <changbin.du@gmail.com> Fixes: 5d8544e2d0 ("RISC-V: Generic library routines and assembly") --- arch/riscv/kernel/stacktrace.c | 6 ++++++ 1 file changed, 6 insertions(+)