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| author | Peter Zijlstra <peterz@infradead.org> | 2021-09-15 18:12:59 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-09-21 14:57:43 +0300 |
| commit | 44b979fa302cab91bdd2cc982823e5c13202cd4e (patch) | |
| tree | 95cda92efb3adb9b44d233dbd979e3ecfd9fa66e /arch/x86/include/asm/stacktrace.h | |
| parent | b968e84b509da593c50dc3db679e1d33de701f78 (diff) | |
| download | linux-44b979fa302cab91bdd2cc982823e5c13202cd4e.tar.xz | |
x86/mm/64: Improve stack overflow warnings
Current code has an explicit check for hitting the task stack guard;
but overflowing any of the other stacks will get you a non-descript
general #DF warning.
Improve matters by using get_stack_info_noinstr() to detetrmine if and
which stack guard page got hit, enabling a better stack warning.
In specific, Michael Wang reported what turned out to be an NMI
exception stack overflow, which is now clearly reported as such:
[] BUG: NMI stack guard page was hit at 0000000085fd977b (stack is 000000003a55b09e..00000000d8cce1a5)
Reported-by: Michael Wang <yun.wang@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Michael Wang <yun.wang@linux.alibaba.com>
Link: https://lkml.kernel.org/r/YUTE/NuqnaWbST8n@hirez.programming.kicks-ass.net
Diffstat (limited to 'arch/x86/include/asm/stacktrace.h')
| -rw-r--r-- | arch/x86/include/asm/stacktrace.h | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h index f248eb2ac2d4..3881b5333eb8 100644 --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -38,6 +38,16 @@ int get_stack_info(unsigned long *stack, struct task_struct *task, bool get_stack_info_noinstr(unsigned long *stack, struct task_struct *task, struct stack_info *info); +static __always_inline +bool get_stack_guard_info(unsigned long *stack, struct stack_info *info) +{ + /* make sure it's not in the stack proper */ + if (get_stack_info_noinstr(stack, current, info)) + return false; + /* but if it is in the page below it, we hit a guard */ + return get_stack_info_noinstr((void *)stack + PAGE_SIZE, current, info); +} + const char *stack_type_name(enum stack_type type); static inline bool on_stack(struct stack_info *info, void *addr, size_t len) |