Commit df835e70 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov

x86/irq/64: Sanitize the top/bottom confusion

On x86, stacks go top to bottom, but the stack overflow check uses it
the other way round, which is just confusing. Clean it up and sanitize
the warning string a bit.
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Reviewed-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Nicolai Stange <nstange@suse.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190414160143.961241397@linutronix.de
parent 4f44b8f0
...@@ -42,7 +42,7 @@ int sysctl_panic_on_stackoverflow; ...@@ -42,7 +42,7 @@ int sysctl_panic_on_stackoverflow;
static inline void stack_overflow_check(struct pt_regs *regs) static inline void stack_overflow_check(struct pt_regs *regs)
{ {
#ifdef CONFIG_DEBUG_STACKOVERFLOW #ifdef CONFIG_DEBUG_STACKOVERFLOW
#define STACK_TOP_MARGIN 128 #define STACK_MARGIN 128
struct orig_ist *oist; struct orig_ist *oist;
u64 irq_stack_top, irq_stack_bottom; u64 irq_stack_top, irq_stack_bottom;
u64 estack_top, estack_bottom; u64 estack_top, estack_bottom;
...@@ -51,25 +51,25 @@ static inline void stack_overflow_check(struct pt_regs *regs) ...@@ -51,25 +51,25 @@ static inline void stack_overflow_check(struct pt_regs *regs)
if (user_mode(regs)) if (user_mode(regs))
return; return;
if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_TOP_MARGIN && if (regs->sp >= curbase + sizeof(struct pt_regs) + STACK_MARGIN &&
regs->sp <= curbase + THREAD_SIZE) regs->sp <= curbase + THREAD_SIZE)
return; return;
irq_stack_bottom = (u64)__this_cpu_read(irq_stack_ptr); irq_stack_top = (u64)__this_cpu_read(irq_stack_ptr);
irq_stack_top = irq_stack_bottom - IRQ_STACK_SIZE + STACK_TOP_MARGIN; irq_stack_bottom = irq_stack_top - IRQ_STACK_SIZE + STACK_MARGIN;
if (regs->sp >= irq_stack_top && regs->sp <= irq_stack_bottom) if (regs->sp >= irq_stack_bottom && regs->sp <= irq_stack_top)
return; return;
oist = this_cpu_ptr(&orig_ist); oist = this_cpu_ptr(&orig_ist);
estack_bottom = (u64)oist->ist[DEBUG_STACK]; estack_top = (u64)oist->ist[DEBUG_STACK];
estack_top = estack_bottom - DEBUG_STKSZ + STACK_TOP_MARGIN; estack_bottom = estack_top - DEBUG_STKSZ + STACK_MARGIN;
if (regs->sp >= estack_top && regs->sp <= estack_bottom) if (regs->sp >= estack_bottom && regs->sp <= estack_top)
return; return;
WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx,irq stk top-bottom:%Lx-%Lx,exception stk top-bottom:%Lx-%Lx,ip:%pF)\n", WARN_ONCE(1, "do_IRQ(): %s has overflown the kernel stack (cur:%Lx,sp:%lx, irq stack:%Lx-%Lx, exception stack: %Lx-%Lx, ip:%pF)\n",
current->comm, curbase, regs->sp, current->comm, curbase, regs->sp,
irq_stack_top, irq_stack_bottom, irq_stack_bottom, irq_stack_top,
estack_top, estack_bottom, (void *)regs->ip); estack_bottom, estack_top, (void *)regs->ip);
if (sysctl_panic_on_stackoverflow) if (sysctl_panic_on_stackoverflow)
panic("low stack detected by irq handler - check messages\n"); panic("low stack detected by irq handler - check messages\n");
......
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