[PATCH] arm:traps: Don't print stack or raw PC/LR values in backtraces
From: Xiaoming Ni
Date: Fri Oct 09 2020 - 04:01:48 EST
Printing raw pointer values in backtraces has potential security
implications and are of questionable value anyway.
This patch follows x86 and arm64's lead and removes the "Exception stack:"
dump from kernel backtraces:
commit a25ffd3a6302a6 ("arm64: traps: Don't print stack or raw
PC/LR values in backtraces")
commit 0ee1dd9f5e7eae ("x86/dumpstack: Remove raw stack dump")
commit bb5e5ce545f203 ("x86/dumpstack: Remove kernel text
addresses from stack dump")
Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx>
---
arch/arm/kernel/process.c | 3 +--
arch/arm/kernel/traps.c | 12 +++++-------
2 files changed, 6 insertions(+), 9 deletions(-)
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c
index 8e6ace03e960..71c9e5597d39 100644
--- a/arch/arm/kernel/process.c
+++ b/arch/arm/kernel/process.c
@@ -121,8 +121,7 @@ void __show_regs(struct pt_regs *regs)
printk("PC is at %pS\n", (void *)instruction_pointer(regs));
printk("LR is at %pS\n", (void *)regs->ARM_lr);
- printk("pc : [<%08lx>] lr : [<%08lx>] psr: %08lx\n",
- regs->ARM_pc, regs->ARM_lr, regs->ARM_cpsr);
+ printk("psr: %08lx\n", regs->ARM_cpsr);
printk("sp : %08lx ip : %08lx fp : %08lx\n",
regs->ARM_sp, regs->ARM_ip, regs->ARM_fp);
printk("r10: %08lx r9 : %08lx r8 : %08lx\n",
diff --git a/arch/arm/kernel/traps.c b/arch/arm/kernel/traps.c
index 17d5a785df28..b0b188e01070 100644
--- a/arch/arm/kernel/traps.c
+++ b/arch/arm/kernel/traps.c
@@ -60,23 +60,18 @@ static int __init user_debug_setup(char *str)
__setup("user_debug=", user_debug_setup);
#endif
-static void dump_mem(const char *, const char *, unsigned long, unsigned long);
-
void dump_backtrace_entry(unsigned long where, unsigned long from,
unsigned long frame, const char *loglvl)
{
unsigned long end = frame + 4 + sizeof(struct pt_regs);
#ifdef CONFIG_KALLSYMS
- printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
- loglvl, where, (void *)where, from, (void *)from);
+ printk("%s (%ps) from (%pS)\n",
+ loglvl, (void *)where, (void *)from);
#else
printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
loglvl, where, from);
#endif
-
- if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
- dump_mem(loglvl, "Exception stack", frame + 4, end);
}
void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
@@ -125,6 +120,9 @@ static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
mm_segment_t fs;
int i;
+ /* Do not print virtual addresses in non-reset scenarios */
+ if (!panic_on_oops)
+ return;
/*
* We need to switch to kernel mode so that we can use __get_user
* to safely read from kernel space. Note that we now dump the
--
2.27.0