From: Will Deacon will.deacon@arm.com
[ Upstream commit a25ffd3a6302a67814280274d8f1aa4ae2ea4b59 ]
Printing raw pointer values in backtraces has potential security implications and are of questionable value anyway.
This patch follows x86's lead and removes the "Exception stack:" dump from kernel backtraces, as well as converting PC/LR values to symbols such as "sysrq_handle_crash+0x20/0x30".
Tested-by: Laura Abbott labbott@redhat.com Signed-off-by: Will Deacon will.deacon@arm.com Signed-off-by: Lee Jones lee.jones@linaro.org --- arch/arm64/kernel/process.c | 8 ++--- arch/arm64/kernel/traps.c | 65 ++----------------------------------- 2 files changed, 6 insertions(+), 67 deletions(-)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index ee5ce03c9315d..2ff327651ebec 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -186,11 +186,9 @@ void __show_regs(struct pt_regs *regs) }
show_regs_print_info(KERN_DEFAULT); - print_symbol("PC is at %s\n", instruction_pointer(regs)); - print_symbol("LR is at %s\n", lr); - printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n", - regs->pc, lr, regs->pstate); - printk("sp : %016llx\n", sp); + print_symbol("pc : %s\n", regs->pc); + print_symbol("lr : %s\n", lr); + printk("sp : %016llx pstate : %08llx\n", sp, regs->pstate);
i = top_reg;
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5ae9c86c30d1d..b30d23431fe11 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -59,55 +59,9 @@ static const char *handler[]= {
int show_unhandled_signals = 0;
-/* - * Dump out the contents of some kernel memory nicely... - */ -static void dump_mem(const char *lvl, const char *str, unsigned long bottom, - unsigned long top) -{ - unsigned long first; - mm_segment_t fs; - int i; - - /* - * We need to switch to kernel mode so that we can use __get_user - * to safely read from kernel space. - */ - fs = get_fs(); - set_fs(KERNEL_DS); - - printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); - - for (first = bottom & ~31; first < top; first += 32) { - unsigned long p; - char str[sizeof(" 12345678") * 8 + 1]; - - memset(str, ' ', sizeof(str)); - str[sizeof(str) - 1] = '\0'; - - for (p = first, i = 0; i < (32 / 8) - && p < top; i++, p += 8) { - if (p >= bottom && p < top) { - unsigned long val; - - if (__get_user(val, (unsigned long *)p) == 0) - sprintf(str + i * 17, " %016lx", val); - else - sprintf(str + i * 17, " ????????????????"); - } - } - printk("%s%04lx:%s\n", lvl, first & 0xffff, str); - } - - set_fs(fs); -} - static void dump_backtrace_entry(unsigned long where) { - /* - * Note that 'where' can have a physical address, but it's not handled. - */ - print_ip_sym(where); + printk(" %pS\n", (void *)where); }
static void __dump_instr(const char *lvl, struct pt_regs *regs) @@ -177,10 +131,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) #endif
printk("Call trace:\n"); - while (1) { - unsigned long stack; - int ret; - + do { /* skip until specified stack frame */ if (!skip) { dump_backtrace_entry(frame.pc); @@ -195,17 +146,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) */ dump_backtrace_entry(regs->pc); } - ret = unwind_frame(tsk, &frame); - if (ret < 0) - break; - if (in_entry_text(frame.pc)) { - stack = frame.fp - offsetof(struct pt_regs, stackframe); - - if (on_accessible_stack(tsk, stack)) - dump_mem("", "Exception stack", stack, - stack + sizeof(struct pt_regs)); - } - } + } while (!unwind_frame(tsk, &frame));
put_task_stack(tsk); }