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| author | Andy Lutomirski <luto@kernel.org> | 2016-09-16 07:45:45 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-09-16 09:18:53 +0200 |
| commit | 1959a60182f48879635812a03a99c02231ea8677 (patch) | |
| tree | 17a624d2b02664dcc0bd218f18b68f8f1f6cad6f /arch/x86/kernel/dumpstack_64.c | |
| parent | kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_k... (diff) | |
| download | linux-1959a60182f48879635812a03a99c02231ea8677.tar.xz linux-1959a60182f48879635812a03a99c02231ea8677.zip | |
x86/dumpstack: Pin the target stack when dumping it
Specifically, pin the stack in save_stack_trace_tsk() and
show_trace_log_lvl().
This will prevent a crash if the target task dies before or while
dumping its stack once we start freeing task stacks early.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jann Horn <jann@thejh.net>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/cf0082cde65d1941a996d026f2b2cdbfaca17bfa.1474003868.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/dumpstack_64.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 8cb6004a4dfd..16c0d5f89b5e 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -218,6 +218,9 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, unsigned long *stack; int i; + if (!try_get_task_stack(task)) + return; + irq_stack_end = (unsigned long *)this_cpu_read(irq_stack_ptr); irq_stack = irq_stack_end - (IRQ_STACK_SIZE / sizeof(long)); @@ -253,6 +256,8 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, pr_cont("\n"); show_trace_log_lvl(task, regs, sp, bp, log_lvl); + + put_task_stack(task); } void show_regs(struct pt_regs *regs) |