From 7d64f82cceb21e6d95db312d284f5f195e120154 Mon Sep 17 00:00:00 2001 From: James Morse Date: Thu, 16 Mar 2017 14:30:39 +0000 Subject: ACPI / APEI: Add missing synchronize_rcu() on NOTIFY_SCI removal When removing a GHES device notified by SCI, list_del_rcu() is used, ghes_remove() should call synchronize_rcu() before it goes on to call kfree(ghes), otherwise concurrent RCU readers may still hold this list entry after it has been freed. Signed-off-by: James Morse Reviewed-by: "Huang, Ying" Fixes: 81e88fdc432a (ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support) Signed-off-by: Rafael J. Wysocki --- drivers/acpi/apei/ghes.c | 1 + 1 file changed, 1 insertion(+) (limited to 'drivers/acpi') diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index b192b42a8351..79b3c9c5a3bc 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -1073,6 +1073,7 @@ static int ghes_remove(struct platform_device *ghes_dev) if (list_empty(&ghes_sci)) unregister_acpi_hed_notifier(&ghes_notifier_sci); mutex_unlock(&ghes_list_mutex); + synchronize_rcu(); break; case ACPI_HEST_NOTIFY_NMI: ghes_nmi_remove(ghes); -- cgit From 61b79e16c68d703dde58c25d3935d67210b7d71b Mon Sep 17 00:00:00 2001 From: Josh Poimboeuf Date: Thu, 16 Mar 2017 08:56:28 -0500 Subject: ACPI: Fix incompatibility with mcount-based function graph tracing Paul Menzel reported a warning: WARNING: CPU: 0 PID: 774 at /build/linux-ROBWaj/linux-4.9.13/kernel/trace/trace_functions_graph.c:233 ftrace_return_to_handler+0x1aa/0x1e0 Bad frame pointer: expected f6919d98, received f6919db0 from func acpi_pm_device_sleep_wake return to c43b6f9d The warning means that function graph tracing is broken for the acpi_pm_device_sleep_wake() function. That's because the ACPI Makefile unconditionally sets the '-Os' gcc flag to optimize for size. That's an issue because mcount-based function graph tracing is incompatible with '-Os' on x86, thanks to the following gcc bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109 I have another patch pending which will ensure that mcount-based function graph tracing is never used with CONFIG_CC_OPTIMIZE_FOR_SIZE on x86. But this patch is needed in addition to that one because the ACPI Makefile overrides that config option for no apparent reason. It has had this flag since the beginning of git history, and there's no related comment, so I don't know why it's there. As far as I can tell, there's no reason for it to be there. The appropriate behavior is for it to honor CONFIG_CC_OPTIMIZE_FOR_{SIZE,PERFORMANCE} like the rest of the kernel. Reported-by: Paul Menzel Signed-off-by: Josh Poimboeuf Acked-by: Steven Rostedt (VMware) Signed-off-by: Rafael J. Wysocki Cc: All applicable --- drivers/acpi/Makefile | 1 - 1 file changed, 1 deletion(-) (limited to 'drivers/acpi') diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index a391bbc48105..d94f92f88ca1 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -2,7 +2,6 @@ # Makefile for the Linux ACPI interpreter # -ccflags-y := -Os ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT # -- cgit