From: Sven Schnelle svens@stackframe.org
[ Upstream commit 8e0ba125c2bf1030af3267058019ba86da96863f ]
With 64 bit kernels unwind_special() is not working because it compares the pc to the address of the function descriptor. Add a helper function that compares pc with the dereferenced address. This fixes all of the backtraces on my c8000. Without this changes, a lot of backtraces are missing in kdb or the show-all-tasks command from /proc/sysrq-trigger.
Signed-off-by: Sven Schnelle svens@stackframe.org Signed-off-by: Helge Deller deller@gmx.de Signed-off-by: Sasha Levin sashal@kernel.org --- arch/parisc/kernel/unwind.c | 21 ++++++++++++++------- 1 file changed, 14 insertions(+), 7 deletions(-)
diff --git a/arch/parisc/kernel/unwind.c b/arch/parisc/kernel/unwind.c index 2d14f17838d23..fa52c939e8a3b 100644 --- a/arch/parisc/kernel/unwind.c +++ b/arch/parisc/kernel/unwind.c @@ -21,6 +21,8 @@ #include <asm/ptrace.h>
#include <asm/unwind.h> +#include <asm/switch_to.h> +#include <asm/sections.h>
/* #define DEBUG 1 */ #ifdef DEBUG @@ -203,6 +205,11 @@ int __init unwind_init(void) return 0; }
+static bool pc_is_kernel_fn(unsigned long pc, void *fn) +{ + return (unsigned long)dereference_kernel_function_descriptor(fn) == pc; +} + static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int frame_size) { /* @@ -221,7 +228,7 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int extern void * const _call_on_stack; #endif /* CONFIG_IRQSTACKS */
- if (pc == (unsigned long) &handle_interruption) { + if (pc_is_kernel_fn(pc, handle_interruption)) { struct pt_regs *regs = (struct pt_regs *)(info->sp - frame_size - PT_SZ_ALGN); dbg("Unwinding through handle_interruption()\n"); info->prev_sp = regs->gr[30]; @@ -229,13 +236,13 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int return 1; }
- if (pc == (unsigned long) &ret_from_kernel_thread || - pc == (unsigned long) &syscall_exit) { + if (pc_is_kernel_fn(pc, ret_from_kernel_thread) || + pc_is_kernel_fn(pc, syscall_exit)) { info->prev_sp = info->prev_ip = 0; return 1; }
- if (pc == (unsigned long) &intr_return) { + if (pc_is_kernel_fn(pc, intr_return)) { struct pt_regs *regs;
dbg("Found intr_return()\n"); @@ -246,20 +253,20 @@ static int unwind_special(struct unwind_frame_info *info, unsigned long pc, int return 1; }
- if (pc == (unsigned long) &_switch_to_ret) { + if (pc_is_kernel_fn(pc, _switch_to) || + pc_is_kernel_fn(pc, _switch_to_ret)) { info->prev_sp = info->sp - CALLEE_SAVE_FRAME_SIZE; info->prev_ip = *(unsigned long *)(info->prev_sp - RP_OFFSET); return 1; }
#ifdef CONFIG_IRQSTACKS - if (pc == (unsigned long) &_call_on_stack) { + if (pc_is_kernel_fn(pc, _call_on_stack)) { info->prev_sp = *(unsigned long *)(info->sp - FRAME_SIZE - REG_SZ); info->prev_ip = *(unsigned long *)(info->sp - FRAME_SIZE - RP_OFFSET); return 1; } #endif - return 0; }