From 4bee96860a65c3a62d332edac331b3cf936ba3ad Mon Sep 17 00:00:00 2001 From: Lai Jiangshan Date: Thu, 31 Jul 2014 11:30:17 +0800 Subject: [PATCH 1/3] smpboot: Add missing get_online_cpus() in smpboot_register_percpu_thread() The following race exists in the smpboot percpu threads management: CPU0 CPU1 cpu_up(2) get_online_cpus(); smpboot_create_threads(2); smpboot_register_percpu_thread(); for_each_online_cpu(); __smpboot_create_thread(); __cpu_up(2); This results in a missing per cpu thread for the newly onlined cpu2 and in a NULL pointer dereference on a consecutive offline of that cpu. Proctect smpboot_register_percpu_thread() with get_online_cpus() to prevent that. [ tglx: Massaged changelog and removed the change in smpboot_unregister_percpu_thread() because that's an optimization and therefor not stable material. ] Signed-off-by: Lai Jiangshan Cc: Thomas Gleixner Cc: Rusty Russell Cc: Peter Zijlstra Cc: Srivatsa S. Bhat Cc: David Rientjes Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1406777421-12830-1-git-send-email-laijs@cn.fujitsu.com Signed-off-by: Thomas Gleixner --- kernel/smpboot.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/smpboot.c b/kernel/smpboot.c index f032fb5284e3..40190f28db35 100644 --- a/kernel/smpboot.c +++ b/kernel/smpboot.c @@ -280,6 +280,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread) unsigned int cpu; int ret = 0; + get_online_cpus(); mutex_lock(&smpboot_threads_lock); for_each_online_cpu(cpu) { ret = __smpboot_create_thread(plug_thread, cpu); @@ -292,6 +293,7 @@ int smpboot_register_percpu_thread(struct smp_hotplug_thread *plug_thread) list_add(&plug_thread->list, &hotplug_threads); out: mutex_unlock(&smpboot_threads_lock); + put_online_cpus(); return ret; } EXPORT_SYMBOL_GPL(smpboot_register_percpu_thread); From 7728b352b78986dd8b0859e213fd59f5e37e4b8e Mon Sep 17 00:00:00 2001 From: Baruch Siach Date: Sun, 25 Jan 2015 15:30:22 +0200 Subject: [PATCH 2/3] tools/liblockdep: ignore generated .so file Signed-off-by: Baruch Siach Signed-off-by: Sasha Levin --- tools/lib/lockdep/.gitignore | 1 + 1 file changed, 1 insertion(+) create mode 100644 tools/lib/lockdep/.gitignore diff --git a/tools/lib/lockdep/.gitignore b/tools/lib/lockdep/.gitignore new file mode 100644 index 000000000000..cc0e7a9f99e3 --- /dev/null +++ b/tools/lib/lockdep/.gitignore @@ -0,0 +1 @@ +liblockdep.so.* From 8baeccdcb8e51bfb0f3349fc8f90abe8d5654f9e Mon Sep 17 00:00:00 2001 From: Baruch Siach Date: Sun, 25 Jan 2015 15:30:23 +0200 Subject: [PATCH 3/3] tools/liblockdep: don't include host headers Adding host headers to include path may cause unexpected surprises when cross compiling. Remove /usr/local/include from the default include path. Signed-off-by: Baruch Siach Signed-off-by: Sasha Levin --- tools/lib/lockdep/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/lib/lockdep/Makefile b/tools/lib/lockdep/Makefile index 52f9279c6c13..4b866c54f624 100644 --- a/tools/lib/lockdep/Makefile +++ b/tools/lib/lockdep/Makefile @@ -104,7 +104,7 @@ N = export Q VERBOSE -INCLUDES = -I. -I/usr/local/include -I./uinclude -I./include -I../../include $(CONFIG_INCLUDES) +INCLUDES = -I. -I./uinclude -I./include -I../../include $(CONFIG_INCLUDES) # Set compile option CFLAGS if not set elsewhere CFLAGS ?= -g -DCONFIG_LOCKDEP -DCONFIG_STACKTRACE -DCONFIG_PROVE_LOCKING -DBITS_PER_LONG=__WORDSIZE -DLIBLOCKDEP_VERSION='"$(LIBLOCKDEP_VERSION)"' -rdynamic -O0 -g