| Message ID | 20210429070348.2167483-1-chenhuang5@huawei.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC] riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabled | expand |
On Thu, 29 Apr 2021 00:03:48 PDT (-0700), chenhuang5@huawei.com wrote: > As [1] and [2] said, the arch_stack_walk should not to trace itself, or it will > leave the trace unexpectedly when called. The example is when we do "cat > /sys/kernel/debug/page_owner", all pages' stack is the same. > > arch_stack_walk+0x18/0x20 > stack_trace_save+0x40/0x60 > register_dummy_stack+0x24/0x5e > init_page_owner+0x2e > > So we use __builtin_frame_address(1) as the first frame to be walked. And mark > the arch_stack_walk() noinline. > > We found that pr_cont will affact pages' stack whose task state is RUNNING when > testing "echo t > /proc/sysrq-trigger". So move the place of pr_cont and mark > the function dump_backtrace() noinline. > > Also we move the case when task == NULL into else branch, and test for it in > "echo c > /proc/sysrq-trigger". > > [1] https://lore.kernel.org/lkml/20210319184106.5688-1-mark.rutland@arm.com/ > [2] https://lore.kernel.org/lkml/20210317142050.57712-1-chenjun102@huawei.com/ > > Signed-off-by: Chen Huang <chenhuang5@huawei.com> > --- > In this way, some crash will loss the print info "Call trace:", likes that: > # echo BUG > /sys/kernel/debug/provoke-crash/DIRECT > [ 61.774690] lkdtm: Performing direct entry BUG > [ 61.775350] ------------[ cut here ]------------ > [ 61.775611] kernel BUG at drivers/misc/lkdtm/bugs.c:76! > [ 61.776073] Kernel BUG [#1] > [ 61.776319] Modules linked in: > [ 61.776696] CPU: 3 PID: 1 Comm: sh Not tainted 5.11.0-rc6-next-20210208-00013-gb16da2c3b9aa #132 > [ 61.777185] Hardware name: riscv-virtio,qemu (DT) > [ 61.777594] epc : lkdtm_BUG+0x6/0x8 > [ 61.777916] ra : lkdtm_do_action+0x14/0x1c > [ 61.778212] epc : ffffffe00048a7e8 ra : ffffffe0006d71a8 sp : ffffffe07fedbd90 > [ 61.778646] gp : ffffffe0012e4208 tp : ffffffe07fed0000 t0 : ffffffe0012f2097 > [ 61.779115] t1 : ffffffe0012f2088 t2 : 0000000000000000 s0 : ffffffe07fedbda0 > [ 61.779588] s1 : 0000000000000010 a0 : ffffffe000c7fbb8 a1 : ffffffe001284d28 > [ 61.780017] a2 : 0000000000000010 a3 : 0000000000000000 a4 : c10724222fbe9200 > [ 61.780473] a5 : ffffffe00048a7e2 a6 : c0000000ffffefff a7 : 0000000000000064 > [ 61.780932] s2 : ffffffe000c7fbc8 s3 : ffffffe000d9e3f8 s4 : ffffffe081969000 > [ 61.781405] s5 : 000000000000004b s6 : 0000000000000004 s7 : ffffffe07fedbe80 > [ 61.781872] s8 : 0000003ffff987e4 s9 : 0000002ab0b7ac50 s10: 0000002ab0bacb90 > [ 61.782336] s11: 0000000000000000 t3 : 000000000000006c t4 : ffffffffffffffff > [ 61.782794] t5 : 0000000000000037 t6 : ffffffe07fedbae8 > [ 61.783158] status: 0000000000000120 badaddr: 0000000000000000 cause: 0000000000000003 > [ 61.783680] [<ffffffe00048a7e8>] lkdtm_BUG+0x6/0x8 > [ 61.784149] [<ffffffe0006d71a8>] lkdtm_do_action+0x14/0x1c > [ 61.784516] [<ffffffe00048a5ee>] direct_entry+0xc0/0x10a > [ 61.784849] [<ffffffe0002498ce>] full_proxy_write+0x42/0x6a > [ 61.785209] [<ffffffe000114b7c>] vfs_write+0x7e/0x218 > [ 61.785562] [<ffffffe000114e84>] ksys_write+0x98/0xc0 > [ 61.785904] [<ffffffe000114eba>] sys_write+0xe/0x16 > [ 61.786275] [<ffffffe000003466>] ret_from_syscall+0x0/0x2 > [ 61.787175] ---[ end trace 6919e7283b64f492 ]--- > [ 61.787707] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b > [ 61.788270] SMP: stopping secondary CPUs > [ 61.788934] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- > > arch/riscv/kernel/stacktrace.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c > index 2b3e0cb90d78..bde85fc53357 100644 > --- a/arch/riscv/kernel/stacktrace.c > +++ b/arch/riscv/kernel/stacktrace.c > @@ -27,10 +27,10 @@ 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 == NULL || task == current) { > - fp = (unsigned long)__builtin_frame_address(0); > - sp = sp_in_global; > - pc = (unsigned long)walk_stackframe; > + } else if (task == current) { > + fp = (unsigned long)__builtin_frame_address(1); > + sp = (unsigned long)__builtin_frame_address(0); > + pc = (unsigned long)__builtin_return_address(0); > } else { > /* task blocked in __switch_to */ > fp = task->thread.s[0]; > @@ -106,15 +106,15 @@ static bool print_trace_address(void *arg, unsigned long pc) > return true; > } > > -void dump_backtrace(struct pt_regs *regs, struct task_struct *task, > +noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task, > const char *loglvl) > { > - pr_cont("%sCall Trace:\n", loglvl); > walk_stackframe(task, regs, print_trace_address, (void *)loglvl); > } > > void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) > { > + pr_cont("%sCall Trace:\n", loglvl); > dump_backtrace(NULL, task, loglvl); > } > > @@ -139,7 +139,7 @@ unsigned long get_wchan(struct task_struct *task) > > #ifdef CONFIG_STACKTRACE > > -void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, > +noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, > struct task_struct *task, struct pt_regs *regs) > { > walk_stackframe(task, regs, consume_entry, cookie); Thanks, this is on fixes.
diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c index 2b3e0cb90d78..bde85fc53357 100644 --- a/arch/riscv/kernel/stacktrace.c +++ b/arch/riscv/kernel/stacktrace.c @@ -27,10 +27,10 @@ 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 == NULL || task == current) { - fp = (unsigned long)__builtin_frame_address(0); - sp = sp_in_global; - pc = (unsigned long)walk_stackframe; + } else if (task == current) { + fp = (unsigned long)__builtin_frame_address(1); + sp = (unsigned long)__builtin_frame_address(0); + pc = (unsigned long)__builtin_return_address(0); } else { /* task blocked in __switch_to */ fp = task->thread.s[0]; @@ -106,15 +106,15 @@ static bool print_trace_address(void *arg, unsigned long pc) return true; } -void dump_backtrace(struct pt_regs *regs, struct task_struct *task, +noinline void dump_backtrace(struct pt_regs *regs, struct task_struct *task, const char *loglvl) { - pr_cont("%sCall Trace:\n", loglvl); walk_stackframe(task, regs, print_trace_address, (void *)loglvl); } void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl) { + pr_cont("%sCall Trace:\n", loglvl); dump_backtrace(NULL, task, loglvl); } @@ -139,7 +139,7 @@ unsigned long get_wchan(struct task_struct *task) #ifdef CONFIG_STACKTRACE -void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, +noinline void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, struct task_struct *task, struct pt_regs *regs) { walk_stackframe(task, regs, consume_entry, cookie);
As [1] and [2] said, the arch_stack_walk should not to trace itself, or it will leave the trace unexpectedly when called. The example is when we do "cat /sys/kernel/debug/page_owner", all pages' stack is the same. arch_stack_walk+0x18/0x20 stack_trace_save+0x40/0x60 register_dummy_stack+0x24/0x5e init_page_owner+0x2e So we use __builtin_frame_address(1) as the first frame to be walked. And mark the arch_stack_walk() noinline. We found that pr_cont will affact pages' stack whose task state is RUNNING when testing "echo t > /proc/sysrq-trigger". So move the place of pr_cont and mark the function dump_backtrace() noinline. Also we move the case when task == NULL into else branch, and test for it in "echo c > /proc/sysrq-trigger". [1] https://lore.kernel.org/lkml/20210319184106.5688-1-mark.rutland@arm.com/ [2] https://lore.kernel.org/lkml/20210317142050.57712-1-chenjun102@huawei.com/ Signed-off-by: Chen Huang <chenhuang5@huawei.com> --- In this way, some crash will loss the print info "Call trace:", likes that: # echo BUG > /sys/kernel/debug/provoke-crash/DIRECT [ 61.774690] lkdtm: Performing direct entry BUG [ 61.775350] ------------[ cut here ]------------ [ 61.775611] kernel BUG at drivers/misc/lkdtm/bugs.c:76! [ 61.776073] Kernel BUG [#1] [ 61.776319] Modules linked in: [ 61.776696] CPU: 3 PID: 1 Comm: sh Not tainted 5.11.0-rc6-next-20210208-00013-gb16da2c3b9aa #132 [ 61.777185] Hardware name: riscv-virtio,qemu (DT) [ 61.777594] epc : lkdtm_BUG+0x6/0x8 [ 61.777916] ra : lkdtm_do_action+0x14/0x1c [ 61.778212] epc : ffffffe00048a7e8 ra : ffffffe0006d71a8 sp : ffffffe07fedbd90 [ 61.778646] gp : ffffffe0012e4208 tp : ffffffe07fed0000 t0 : ffffffe0012f2097 [ 61.779115] t1 : ffffffe0012f2088 t2 : 0000000000000000 s0 : ffffffe07fedbda0 [ 61.779588] s1 : 0000000000000010 a0 : ffffffe000c7fbb8 a1 : ffffffe001284d28 [ 61.780017] a2 : 0000000000000010 a3 : 0000000000000000 a4 : c10724222fbe9200 [ 61.780473] a5 : ffffffe00048a7e2 a6 : c0000000ffffefff a7 : 0000000000000064 [ 61.780932] s2 : ffffffe000c7fbc8 s3 : ffffffe000d9e3f8 s4 : ffffffe081969000 [ 61.781405] s5 : 000000000000004b s6 : 0000000000000004 s7 : ffffffe07fedbe80 [ 61.781872] s8 : 0000003ffff987e4 s9 : 0000002ab0b7ac50 s10: 0000002ab0bacb90 [ 61.782336] s11: 0000000000000000 t3 : 000000000000006c t4 : ffffffffffffffff [ 61.782794] t5 : 0000000000000037 t6 : ffffffe07fedbae8 [ 61.783158] status: 0000000000000120 badaddr: 0000000000000000 cause: 0000000000000003 [ 61.783680] [<ffffffe00048a7e8>] lkdtm_BUG+0x6/0x8 [ 61.784149] [<ffffffe0006d71a8>] lkdtm_do_action+0x14/0x1c [ 61.784516] [<ffffffe00048a5ee>] direct_entry+0xc0/0x10a [ 61.784849] [<ffffffe0002498ce>] full_proxy_write+0x42/0x6a [ 61.785209] [<ffffffe000114b7c>] vfs_write+0x7e/0x218 [ 61.785562] [<ffffffe000114e84>] ksys_write+0x98/0xc0 [ 61.785904] [<ffffffe000114eba>] sys_write+0xe/0x16 [ 61.786275] [<ffffffe000003466>] ret_from_syscall+0x0/0x2 [ 61.787175] ---[ end trace 6919e7283b64f492 ]--- [ 61.787707] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 61.788270] SMP: stopping secondary CPUs [ 61.788934] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- arch/riscv/kernel/stacktrace.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)