diff options
Diffstat (limited to 'freed-ora/tags/f27/4.15.9-300.fc27.gnu/0001-x86-MCE-Serialize-sysfs-changes.patch')
| -rw-r--r-- | freed-ora/tags/f27/4.15.9-300.fc27.gnu/0001-x86-MCE-Serialize-sysfs-changes.patch | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/freed-ora/tags/f27/4.15.9-300.fc27.gnu/0001-x86-MCE-Serialize-sysfs-changes.patch b/freed-ora/tags/f27/4.15.9-300.fc27.gnu/0001-x86-MCE-Serialize-sysfs-changes.patch new file mode 100644 index 000000000..84c7b7fd3 --- /dev/null +++ b/freed-ora/tags/f27/4.15.9-300.fc27.gnu/0001-x86-MCE-Serialize-sysfs-changes.patch @@ -0,0 +1,114 @@ +From b3b7c4795ccab5be71f080774c45bbbcc75c2aaf Mon Sep 17 00:00:00 2001 +From: Seunghun Han <kkamagui@gmail.com> +Date: Tue, 6 Mar 2018 15:21:43 +0100 +Subject: [PATCH] x86/MCE: Serialize sysfs changes + +The check_interval file in + + /sys/devices/system/machinecheck/machinecheck<cpu number> + +directory is a global timer value for MCE polling. If it is changed by one +CPU, mce_restart() broadcasts the event to other CPUs to delete and restart +the MCE polling timer and __mcheck_cpu_init_timer() reinitializes the +mce_timer variable. + +If more than one CPU writes a specific value to the check_interval file +concurrently, mce_timer is not protected from such concurrent accesses and +all kinds of explosions happen. Since only root can write to those sysfs +variables, the issue is not a big deal security-wise. + +However, concurrent writes to these configuration variables is void of +reason so the proper thing to do is to serialize the access with a mutex. + +Boris: + + - Make store_int_with_restart() use device_store_ulong() to filter out + negative intervals + - Limit min interval to 1 second + - Correct locking + - Massage commit message + +Signed-off-by: Seunghun Han <kkamagui@gmail.com> +Signed-off-by: Borislav Petkov <bp@suse.de> +Signed-off-by: Thomas Gleixner <tglx@linutronix.de> +Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Cc: Tony Luck <tony.luck@intel.com> +Cc: linux-edac <linux-edac@vger.kernel.org> +Cc: stable@vger.kernel.org +Link: http://lkml.kernel.org/r/20180302202706.9434-1-kkamagui@gmail.com +--- + arch/x86/kernel/cpu/mcheck/mce.c | 22 +++++++++++++++++++++- + 1 file changed, 21 insertions(+), 1 deletion(-) + +diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c +index b3323cab9139..466f47301334 100644 +--- a/arch/x86/kernel/cpu/mcheck/mce.c ++++ b/arch/x86/kernel/cpu/mcheck/mce.c +@@ -56,6 +56,9 @@ + + static DEFINE_MUTEX(mce_log_mutex); + ++/* sysfs synchronization */ ++static DEFINE_MUTEX(mce_sysfs_mutex); ++ + #define CREATE_TRACE_POINTS + #include <trace/events/mce.h> + +@@ -2088,6 +2091,7 @@ static ssize_t set_ignore_ce(struct device *s, + if (kstrtou64(buf, 0, &new) < 0) + return -EINVAL; + ++ mutex_lock(&mce_sysfs_mutex); + if (mca_cfg.ignore_ce ^ !!new) { + if (new) { + /* disable ce features */ +@@ -2100,6 +2104,8 @@ static ssize_t set_ignore_ce(struct device *s, + on_each_cpu(mce_enable_ce, (void *)1, 1); + } + } ++ mutex_unlock(&mce_sysfs_mutex); ++ + return size; + } + +@@ -2112,6 +2118,7 @@ static ssize_t set_cmci_disabled(struct device *s, + if (kstrtou64(buf, 0, &new) < 0) + return -EINVAL; + ++ mutex_lock(&mce_sysfs_mutex); + if (mca_cfg.cmci_disabled ^ !!new) { + if (new) { + /* disable cmci */ +@@ -2123,6 +2130,8 @@ static ssize_t set_cmci_disabled(struct device *s, + on_each_cpu(mce_enable_ce, NULL, 1); + } + } ++ mutex_unlock(&mce_sysfs_mutex); ++ + return size; + } + +@@ -2130,8 +2139,19 @@ static ssize_t store_int_with_restart(struct device *s, + struct device_attribute *attr, + const char *buf, size_t size) + { +- ssize_t ret = device_store_int(s, attr, buf, size); ++ unsigned long old_check_interval = check_interval; ++ ssize_t ret = device_store_ulong(s, attr, buf, size); ++ ++ if (check_interval == old_check_interval) ++ return ret; ++ ++ if (check_interval < 1) ++ check_interval = 1; ++ ++ mutex_lock(&mce_sysfs_mutex); + mce_restart(); ++ mutex_unlock(&mce_sysfs_mutex); ++ + return ret; + } + +-- +2.14.3 + |
