3.16.57-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Will Deacon <will.deacon@xxxxxxx>
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@xxxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
[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@xxxxxxxxxxxxxxx>
---
--- 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)
