Messages in this thread Patch in this message | | | From | Naoya Horiguchi <> | Subject | [PATCH] MCE: fix return value of mce_chrdev_read() when erst is disabled | Date | Mon, 23 Jan 2012 15:54:52 -0500 |
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Current kernel MCE code reads ERST at the first reading of /dev/mcelog (maybe in starting mcelogd,) even if the system does not support ERST, which results in a fake "no such device" message (as described in [1].) This problem is not critical, but can confuse system admins. This patch fixes it by filtering the return value from lower (ACPI) layer.
[1] http://thread.gmane.org/gmane.linux.kernel/1060250
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Huang Ying <ying.huang@intel.com> --- arch/x86/kernel/cpu/mcheck/mce.c | 6 ++++++ 1 files changed, 6 insertions(+), 0 deletions(-)
diff --git 3.3-rc1.orig/arch/x86/kernel/cpu/mcheck/mce.c 3.3-rc1/arch/x86/kernel/cpu/mcheck/mce.c index 5a11ae2..8ee5c4f 100644 --- 3.3-rc1.orig/arch/x86/kernel/cpu/mcheck/mce.c +++ 3.3-rc1/arch/x86/kernel/cpu/mcheck/mce.c @@ -1541,6 +1541,12 @@ static int __mce_read_apei(char __user **ubuf, size_t usize) /* Error or no more MCE record */ if (rc <= 0) { mce_apei_read_done = 1; + /* + * When ERST is disabled, mce_chrdev_read() should return + * "no record" instead of "no device." + */ + if (rc == -ENODEV) + return 0; return rc; } rc = -EFAULT; -- 1.7.6.5
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