diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2021-09-15 17:12:59 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-09-21 13:57:43 +0200 |
| commit | 44b979fa302cab91bdd2cc982823e5c13202cd4e (patch) | |
| tree | 95cda92efb3adb9b44d233dbd979e3ecfd9fa66e /arch/x86/mm/fault.c | |
| parent | b968e84b509da593c50dc3db679e1d33de701f78 (diff) | |
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/mm/fault.c')
| -rw-r--r-- | arch/x86/mm/fault.c | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index b2eefdefc108..edb5152f0866 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -32,6 +32,7 @@ #include <asm/pgtable_areas.h> /* VMALLOC_START, ... */ #include <asm/kvm_para.h> /* kvm_handle_async_pf */ #include <asm/vdso.h> /* fixup_vdso_exception() */ +#include <asm/irq_stack.h> #define CREATE_TRACE_POINTS #include <asm/trace/exceptions.h> @@ -631,6 +632,9 @@ static noinline void page_fault_oops(struct pt_regs *regs, unsigned long error_code, unsigned long address) { +#ifdef CONFIG_VMAP_STACK + struct stack_info info; +#endif unsigned long flags; int sig; @@ -649,9 +653,7 @@ page_fault_oops(struct pt_regs *regs, unsigned long error_code, * that we're in vmalloc space to avoid this. */ if (is_vmalloc_addr((void *)address) && - (((unsigned long)current->stack - 1 - address < PAGE_SIZE) || - address - ((unsigned long)current->stack + THREAD_SIZE) < PAGE_SIZE)) { - unsigned long stack = __this_cpu_ist_top_va(DF) - sizeof(void *); + get_stack_guard_info((void *)address, &info)) { /* * We're likely to be running with very little stack space * left. It's plausible that we'd hit this condition but @@ -662,13 +664,11 @@ page_fault_oops(struct pt_regs *regs, unsigned long error_code, * and then double-fault, though, because we're likely to * break the console driver and lose most of the stack dump. */ - asm volatile ("movq %[stack], %%rsp\n\t" - "call handle_stack_overflow\n\t" - "1: jmp 1b" - : ASM_CALL_CONSTRAINT - : "D" ("kernel stack overflow (page fault)"), - "S" (regs), "d" (address), - [stack] "rm" (stack)); + call_on_stack(__this_cpu_ist_top_va(DF) - sizeof(void*), + handle_stack_overflow, + ASM_CALL_ARG3, + , [arg1] "r" (regs), [arg2] "r" (address), [arg3] "r" (&info)); + unreachable(); } #endif |