6.18-stable review patch. If anyone has any objections, please let me know.
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From: Peter Zijlstra peterz@infradead.org
[ Upstream commit cf76553aaa363620f58a6b6409bf544f4bcfa8de ]
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: c6439bfaabf2 ("Merge tag 'trace-deferred-unwind-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace") Reported-by: Stephen Rothwell sfr@canb.auug.org.au Reported-by: Ingo Molnar mingo@kernel.org Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Link: https://patch.msgid.link/20251105100014.GY4068168@noisy.programming.kicks-as... Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/irq-entry-common.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/irq-entry-common.h b/include/linux/irq-entry-common.h index d643c7c87822e..ba1ed42f8a1c2 100644 --- a/include/linux/irq-entry-common.h +++ b/include/linux/irq-entry-common.h @@ -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);