Commit-ID: 5fe599e02e41550c59831613a11c8ae057897c29 Gitweb: http://git.kernel.org/tip/5fe599e02e41550c59831613a11c8ae057897c29 Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> AuthorDate: Wed, 14 Sep 2016 21:07:43 -0500 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Thu, 15 Sep 2016 08:13:15 +0200 x86/dumpstack: Add support for unwinding empty IRQ stacks When an interrupt happens in entry code while running on a software IRQ stack, and the IRQ stack was empty, regs->sp will contain the stack end address (e.g., irq_stack_ptr). If the regs are passed to dump_trace(), get_stack_info() will report STACK_TYPE_UNKNOWN, causing dump_trace() to return prematurely without trying to go to the next stack. Update the bounds checking for software interrupt stacks so that the ending address is now considered part of the stack. This means that it's now possible for the 'walk_stack' callbacks -- print_context_stack() and print_context_stack_bp() -- to be called with an empty stack. But that's fine; they're already prepared to deal with that due to their on_stack() checks. Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: Brian Gerst <brgerst@xxxxxxxxx> Cc: Byungchul Park <byungchul.park@xxxxxxx> Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx> Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Nilay Vaish <nilayvaish@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: http://lkml.kernel.org/r/5a5e5de92dcf11e8dc6b6e8e50ad7639d067830b.1473905218.git.jpoimboe@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/dumpstack_32.c | 12 ++++++++++-- arch/x86/kernel/dumpstack_64.c | 6 +++++- 2 files changed, 15 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index c92da5a..50076d4 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -35,7 +35,11 @@ static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info) unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack); unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); - if (stack < begin || stack >= end) + /* + * This is a software stack, so 'end' can be a valid stack pointer. + * It just means the stack is empty. + */ + if (stack < begin || stack > end) return false; info->type = STACK_TYPE_IRQ; @@ -56,7 +60,11 @@ static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack); unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); - if (stack < begin || stack >= end) + /* + * This is a software stack, so 'end' can be a valid stack pointer. + * It just means the stack is empty. + */ + if (stack < begin || stack > end) return false; info->type = STACK_TYPE_SOFTIRQ; diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 41813ab..2e708af 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -90,7 +90,11 @@ static bool in_irq_stack(unsigned long *stack, struct stack_info *info) unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr); unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long)); - if (stack < begin || stack >= end) + /* + * This is a software stack, so 'end' can be a valid stack pointer. + * It just means the stack is empty. + */ + if (stack < begin || stack > end) return false; info->type = STACK_TYPE_IRQ; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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