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ARM: 9233/1: stacktrace: Skip frame pointer boundary check for call_with_stack()

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When using the frame pointer unwinder, it was found that the stack trace
output of stack_trace_save() is incomplete if the stack contains
call_with_stack():

 [0x7f00002c] dump_stack_task+0x2c/0x90 [hrtimer]
 [0x7f0000a0] hrtimer_hander+0x10/0x18 [hrtimer]
 [0x801a67f0] __hrtimer_run_queues+0x1b0/0x3b4
 [0x801a7350] hrtimer_run_queues+0xc4/0xd8
 [0x801a597c] update_process_times+0x3c/0x88
 [0x801b5a98] tick_periodic+0x50/0xd8
 [0x801b5bf4] tick_handle_periodic+0x24/0x84
 [0x8010ffc4] twd_handler+0x38/0x48
 [0x8017d220] handle_percpu_devid_irq+0xa8/0x244
 [0x80176e9c] generic_handle_domain_irq+0x2c/0x3c
 [0x8052e3a8] gic_handle_irq+0x7c/0x90
 [0x808ab15c] generic_handle_arch_irq+0x60/0x80
 [0x8051191c] call_with_stack+0x1c/0x20

For the frame pointer unwinder, unwind_frame() checks stackframe::fp by
stackframe::sp. Since call_with_stack() switches the SP from one stack
to another, stackframe::fp and stackframe: :sp will point to different
stacks, so we can no longer check stackframe::fp by stackframe::sp. Skip
checking stackframe::fp at this point to avoid this problem.

Signed-off-by: Li Huafei <lihuafei1@huawei.com>
Reviewed-by: Linus Waleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
This commit is contained in:
Li Huafei 2022-08-26 09:06:22 +01:00 committed by Russell King (Oracle)
parent 09cffecaa7
commit 5854e4d853
2 changed files with 35 additions and 7 deletions
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40
arch/arm/kernel/stacktrace.c
View File

@ -9,6 +9,8 @@
#include <asm/stacktrace.h>
#include <asm/traps.h>
#include "reboot.h"
#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
/*
* Unwind the current stack frame and store the new register values in the
@ -39,29 +41,53 @@
* Note that with framepointer enabled, even the leaf functions have the same
* prologue and epilogue, therefore we can ignore the LR value in this case.
*/
int notrace unwind_frame(struct stackframe *frame)
extern unsigned long call_with_stack_end;
static int frame_pointer_check(struct stackframe *frame)
{
unsigned long high, low;
unsigned long fp = frame->fp;
unsigned long pc = frame->pc;
/*
* call_with_stack() is the only place we allow SP to jump from one
* stack to another, with FP and SP pointing to different stacks,
* skipping the FP boundary check at this point.
*/
if (pc >= (unsigned long)&call_with_stack &&
pc < (unsigned long)&call_with_stack_end)
return 0;
/* only go to a higher address on the stack */
low = frame->sp;
high = ALIGN(low, THREAD_SIZE);
#ifdef CONFIG_CC_IS_CLANG
/* check current frame pointer is within bounds */
#ifdef CONFIG_CC_IS_CLANG
if (fp < low + 4 || fp > high - 4)
return -EINVAL;
#else
if (fp < low + 12 || fp > high - 4)
return -EINVAL;
#endif
return 0;
}
int notrace unwind_frame(struct stackframe *frame)
{
unsigned long fp = frame->fp;
if (frame_pointer_check(frame))
return -EINVAL;
/* restore the registers from the stack frame */
#ifdef CONFIG_CC_IS_CLANG
frame->sp = frame->fp;
frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 4));
#else
/* check current frame pointer is within bounds */
if (fp < low + 12 || fp > high - 4)
return -EINVAL;
/* restore the registers from the stack frame */
frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 12));
frame->sp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 8));
frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 4));

2
arch/arm/lib/call_with_stack.S
View File

@ -46,4 +46,6 @@ UNWIND( .setfp fpreg, sp )
pop {fpreg, pc}
UNWIND( .fnend )
#endif
.globl call_with_stack_end
call_with_stack_end:
ENDPROC(call_with_stack)