Commit ab1e29ac authored by Eric Chan's avatar Eric Chan Committed by Catalin Marinas
Browse files

arm64: lockdep: enable checks for held locks when returning to userspace 



Currently arm64 doesn't use CONFIG_GENERIC_ENTRY and doesn't call
lockdep_sys_exit() when returning to userspace.
This means that lockdep won't check for held locks when
returning to userspace, which would be useful to detect kernel bugs.

Call lockdep_sys_exit() when returning to userspace,
enabling checking for held locks.

At the same time, rename arm64's prepare_exit_to_user_mode() to
exit_to_user_mode_prepare() to more clearly align with the naming
in the generic entry code.

Signed-off-by: default avatarEric Chan <ericchancf@google.com>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230531090909.357047-1-ericchancf@google.com


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 56b77ba1

arch/arm64/kernel/entry-common.c

+4 −2
Original line number Diff line number Diff line
@@ -126,7 +126,7 @@ static __always_inline void __exit_to_user_mode(void) 
	lockdep_hardirqs_on(CALLER_ADDR0);

}



static __always_inline void prepare_exit_to_user_mode(struct pt_regs *regs)

static __always_inline void exit_to_user_mode_prepare(struct pt_regs *regs)

{

	unsigned long flags;
@@ -135,11 +135,13 @@ static __always_inline void prepare_exit_to_user_mode(struct pt_regs *regs) 
	flags = read_thread_flags();

	if (unlikely(flags & _TIF_WORK_MASK))

		do_notify_resume(regs, flags);



	lockdep_sys_exit();

}



static __always_inline void exit_to_user_mode(struct pt_regs *regs)

{

	prepare_exit_to_user_mode(regs);

	exit_to_user_mode_prepare(regs);

	mte_check_tfsr_exit();

	__exit_to_user_mode();

}