Commit ce6e85a1 authored by Benjamin Berg's avatar Benjamin Berg Committed by Johannes Berg
Browse files

um: remove broken double fault detection 



The show_stack function had some code to detect double faults. However,
the logic is wrong and it would e.g. trigger if a WARNING happened
inside an IRQ.

Remove it without trying to add a new logic. The current behaviour,
which will just fault repeatedly until the IRQ stack is used up and the
host kills UML, seems to be good enough.

Signed-off-by: default avatarBenjamin Berg <benjamin.berg@intel.com>
Link: https://patch.msgid.link/20241103150506.1367695-5-benjamin@sipsolutions.net


Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent b69f22df

arch/um/include/shared/os.h

+0 −1
Original line number Diff line number Diff line
@@ -241,7 +241,6 @@ extern void block_signals(void); 
extern void unblock_signals(void);

extern int um_set_signals(int enable);

extern int um_set_signals_trace(int enable);

extern int os_is_signal_stack(void);

extern void deliver_alarm(void);

extern void register_pm_wake_signal(void);

extern void block_signals_hard(void);

arch/um/kernel/sysrq.c

+0 −6
Original line number Diff line number Diff line
@@ -32,12 +32,6 @@ void show_stack(struct task_struct *task, unsigned long *stack, 
	struct pt_regs *segv_regs = current->thread.segv_regs;

	int i;



	if (!segv_regs && os_is_signal_stack()) {

		pr_err("Received SIGSEGV in SIGSEGV handler,"

				" aborting stack trace!\n");

		return;

	}



	if (!stack)

		stack = get_stack_pointer(task, segv_regs);

arch/um/os-Linux/signal.c

+0 −8
Original line number Diff line number Diff line
@@ -487,11 +487,3 @@ void unblock_signals_hard(void) 
	unblocking = false;

}

#endif
 


int os_is_signal_stack(void)

{

	stack_t ss;

	sigaltstack(NULL, &ss);



	return ss.ss_flags & SS_ONSTACK;

}