Commit cf76553a authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

entry,unwind/deferred: Fix unwind_reset_info() placement 

Stephen reported that on KASAN builds he's seeing:

vmlinux.o: warning: objtool: user_exc_vmm_communication+0x15a: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_debug_user+0x182: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: exc_int3+0x123: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: noist_exc_machine_check+0x17a: call to __kasan_check_read() leaves .noinstr.text section
vmlinux.o: warning: objtool: fred_exc_machine_check+0x17e: call to __kasan_check_read() leaves .noinstr.text section

This turns out to be atomic ops from unwind_reset_info() that have
explicit instrumentation. Place unwind_reset_info() in the preceding
instrumentation_begin() section.

Fixes: c6439bfa ("Merge tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace"

)
Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
Reported-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251105100014.GY4068168@noisy.programming.kicks-ass.net
parent aa7387e7

include/linux/irq-entry-common.h

+1 −1
Original line number Diff line number Diff line
@@ -253,11 +253,11 @@ static __always_inline void exit_to_user_mode_prepare(struct pt_regs *regs) 
static __always_inline void exit_to_user_mode(void)

{

	instrumentation_begin();

	unwind_reset_info();

	trace_hardirqs_on_prepare();

	lockdep_hardirqs_on_prepare();

	instrumentation_end();



	unwind_reset_info();

	user_enter_irqoff();

	arch_exit_to_user_mode();

	lockdep_hardirqs_on(CALLER_ADDR0);