3.16.57-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon will.deacon@arm.com
commit a25ffd3a6302a67814280274d8f1aa4ae2ea4b59 upstream.
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 [bwh: Backported to 3.16: - Deleted code in dump_mem() and dump_backtrace_entry() is a bit different - Leave dump_backtrace() unchanged, since it doesn't use dump_mem()] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -198,11 +198,9 @@ 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); for (i = top_reg; i >= 0; i--) { printk("x%-2d: %016llx ", i, regs->regs[i]); if (i % 2 == 0) --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -47,53 +47,9 @@ static const char *handler[]= {
int show_unhandled_signals = 1;
-/* - * Dump out the contents of some 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 < 8 && p < top; i++, p += 4) { - if (p >= bottom && p < top) { - unsigned int val; - if (__get_user(val, (unsigned int *)p) == 0) - sprintf(str + i * 9, " %08x", val); - else - sprintf(str + i * 9, " ????????"); - } - } - printk("%s%04lx:%s\n", lvl, first & 0xffff, str); - } - - set_fs(fs); -} - static void dump_backtrace_entry(unsigned long where, unsigned long stack) { - print_ip_sym(where); - if (in_exception_text(where)) - dump_mem("", "Exception stack", stack, - stack + sizeof(struct pt_regs)); + printk(" %pS\n", (void *)where); }
static void __dump_instr(const char *lvl, struct pt_regs *regs)