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riscv: stacktrace: Make walk_stackframe cross pt_regs frame

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The current walk_stackframe with FRAME_POINTER would stop unwinding at
ret_from_exception:
  BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1518
  in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: init
  CPU: 0 PID: 1 Comm: init Not tainted 5.10.113-00021-g15c15974895c-dirty #192
  Call Trace:
  [<ffffffe0002038c8>] walk_stackframe+0x0/0xee
  [<ffffffe000aecf48>] show_stack+0x32/0x4a
  [<ffffffe000af1618>] dump_stack_lvl+0x72/0x8e
  [<ffffffe000af1648>] dump_stack+0x14/0x1c
  [<ffffffe000239ad2>] ___might_sleep+0x12e/0x138
  [<ffffffe000239aec>] __might_sleep+0x10/0x18
  [<ffffffe000afe3fe>] down_read+0x22/0xa4
  [<ffffffe000207588>] do_page_fault+0xb0/0x2fe
  [<ffffffe000201b80>] ret_from_exception+0x0/0xc

The optimization would help walk_stackframe cross the pt_regs frame and
get more backtrace of debug info:
  BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1518
  in_atomic(): 0, irqs_disabled(): 1, non_block: 0, pid: 1, name: init
  CPU: 0 PID: 1 Comm: init Not tainted 5.10.113-00021-g15c15974895c-dirty #192
  Call Trace:
  [<ffffffe0002038c8>] walk_stackframe+0x0/0xee
  [<ffffffe000aecf48>] show_stack+0x32/0x4a
  [<ffffffe000af1618>] dump_stack_lvl+0x72/0x8e
  [<ffffffe000af1648>] dump_stack+0x14/0x1c
  [<ffffffe000239ad2>] ___might_sleep+0x12e/0x138
  [<ffffffe000239aec>] __might_sleep+0x10/0x18
  [<ffffffe000afe3fe>] down_read+0x22/0xa4
  [<ffffffe000207588>] do_page_fault+0xb0/0x2fe
  [<ffffffe000201b80>] ret_from_exception+0x0/0xc
  [<ffffffe000613c06>] riscv_intc_irq+0x1a/0x72
  [<ffffffe000201b80>] ret_from_exception+0x0/0xc
  [<ffffffe00033f44a>] vma_link+0x54/0x160
  [<ffffffe000341d7a>] mmap_region+0x2cc/0x4d0
  [<ffffffe000342256>] do_mmap+0x2d8/0x3ac
  [<ffffffe000326318>] vm_mmap_pgoff+0x70/0xb8
  [<ffffffe00032638a>] vm_mmap+0x2a/0x36
  [<ffffffe0003cfdde>] elf_map+0x72/0x84
  [<ffffffe0003d05f8>] load_elf_binary+0x69a/0xec8
  [<ffffffe000376240>] bprm_execve+0x246/0x53a
  [<ffffffe00037786c>] kernel_execve+0xe8/0x124
  [<ffffffe000aecdf2>] run_init_process+0xfa/0x10c
  [<ffffffe000aece16>] try_to_run_init_process+0x12/0x3c
  [<ffffffe000afa920>] kernel_init+0xb4/0xf8
  [<ffffffe000201b80>] ret_from_exception+0x0/0xc

Here is the error injection test code for the above output:
 drivers/irqchip/irq-riscv-intc.c:
 static asmlinkage void riscv_intc_irq(struct pt_regs *regs)
 {
        unsigned long cause = regs->cause & ~CAUSE_IRQ_FLAG;
+       u32 tmp; __get_user(tmp, (u32 *)0);

Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Link: https://lore.kernel.org/r/20221109064937.3643993-3-guoren@kernel.org
[Palmer: use SYM_CODE_*]
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Guo Ren 2022-11-09 01:49:37 -05:00 committed by Palmer Dabbelt
parent 5c3022e4a6
commit 7ecdadf7f8
No known key found for this signature in database
GPG Key ID: 2E1319F35FBB1889
2 changed files with 11 additions and 1 deletions
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3
arch/riscv/kernel/entry.S
View File

@ -248,7 +248,7 @@ ret_from_syscall_rejected:
andi t0, t0, _TIF_SYSCALL_WORK
bnez t0, handle_syscall_trace_exit
ret_from_exception:
SYM_CODE_START_NOALIGN(ret_from_exception)
REG_L s0, PT_STATUS(sp)
csrc CSR_STATUS, SR_IE
#ifdef CONFIG_TRACE_IRQFLAGS
@ -262,6 +262,7 @@ ret_from_exception:
andi s0, s0, SR_SPP
#endif
bnez s0, resume_kernel
SYM_CODE_END(ret_from_exception)
resume_userspace:
/* Interrupts must be disabled here so flags are checked atomically */

9
arch/riscv/kernel/stacktrace.c
View File

@ -16,6 +16,8 @@
#ifdef CONFIG_FRAME_POINTER
extern asmlinkage void ret_from_exception(void);
void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
bool (*fn)(void *, unsigned long), void *arg)
{
@ -59,6 +61,13 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
fp = frame->fp;
pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
&frame->ra);
if (pc == (unsigned long)ret_from_exception) {
if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))
break;
pc = ((struct pt_regs *)sp)->epc;
fp = ((struct pt_regs *)sp)->s0;
}
}
}