Recent change to struct pt_regs handling in entry.S, among other things, changed how callee-preserved registers are saved around call to lockdep_sys_exit_thunk:
# define LOCKDEP_SYS_EXIT_IRQ \ TRACE_IRQS_ON; \ sti; \ SAVE_EXTRA_REGS; \ <======= HERE LOCKDEP_SYS_EXIT; \ RESTORE_EXTRA_REGS; \ <======= HERE The change is in fact a bit fragile: now we assume that LOCKDEP_SYS_EXIT_IRQ macro is used only when there is a struct pt_regs on the stack. So far this assumption is true, but it is probably a coincidence. We can revert back to pushing registers, but this callee-preserved registers saving appears bogus. It is not necessary: they _are_ callee-preserved, and lockdep_sys_exit() does not touch them on the stack either. First two patches clean up #define maze so that we can see that LOCKDEP_SYS_EXIT macro call above is merely "call lockdep_sys_exit_thunk". Last patch removes SAVE/RESTORE. I tested this patch series and everything seems to run fine on a lockdep-enabled kernel with these lines removed. Denys Vlasenko (3): x86: move ARCH_LOCKDEP_SYS_EXIT[IRQ] defines closer to their users x86: fold ARCH_LOCKDEP_SYS_EXIT defines into their users x86: do not save callee-preserved registers around lockdep_sys_exit_thunk arch/x86/include/asm/irqflags.h | 45 +++++++++++++++++------------------------ 1 file changed, 19 insertions(+), 26 deletions(-) CC: Linus Torvalds <torva...@linux-foundation.org> CC: Steven Rostedt <rost...@goodmis.org> CC: Ingo Molnar <mi...@kernel.org> CC: Borislav Petkov <b...@alien8.de> CC: "H. Peter Anvin" <h...@zytor.com> CC: Andy Lutomirski <l...@amacapital.net> CC: Oleg Nesterov <o...@redhat.com> CC: Frederic Weisbecker <fweis...@gmail.com> CC: Alexei Starovoitov <a...@plumgrid.com> CC: Will Drewry <w...@chromium.org> CC: Kees Cook <keesc...@chromium.org> CC: x...@kernel.org CC: linux-kernel@vger.kernel.org -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/