path: root/arch/arm64/kernel
diff options
authorMark Rutland <mark.rutland@arm.com>2017-08-07 12:10:51 +0100
committerMark Rutland <mark.rutland@arm.com>2017-08-15 18:34:39 +0100
commitc5bc503cbeee8586395aa541d2b53c69c3dd6930 (patch)
treead34539a7e683b5628ae787e749c9f9090b3eda8 /arch/arm64/kernel
parentarm64: unwind: remove sp from struct stackframe (diff)
arm64: remove __die()'s stack dump
Our __die() implementation tries to dump the stack memory, in addition to a backtrace, which is problematic. For contemporary 16K stacks, this can be a lot of data, which can take a long time to dump, and can push other useful context out of the kernel's printk ringbuffer (and/or a user's scrollback buffer on an attached console). Additionally, the code implicitly assumes that the SP is on the task's stack, and tries to dump everything between the SP and the highest task stack address. When the SP points at an IRQ stack (or is corrupted), this makes the kernel attempt to dump vast amounts of VA space. With vmap'd stacks, this may result in erroneous accesses to peripherals. This patch removes the memory dump, leaving us to rely on the backtrace, and other means of dumping stack memory such as kdump. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Will Deacon <will.deacon@arm.com> Tested-by: Laura Abbott <labbott@redhat.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: James Morse <james.morse@arm.com>
Diffstat (limited to 'arch/arm64/kernel')
1 files changed, 0 insertions, 2 deletions
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index c2a81bf8827e..9633773ca42c 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -237,8 +237,6 @@ static int __die(const char *str, int err, struct pt_regs *regs)
if (!user_mode(regs)) {
- dump_mem(KERN_EMERG, "Stack: ", regs->sp,
- THREAD_SIZE + (unsigned long)task_stack_page(tsk));
dump_backtrace(regs, tsk);
dump_instr(KERN_EMERG, regs);