kernel.git/arch/x86/kernel/cpu/mcheck, branch linux-4.13.y

x86/MCE/AMD: Always give panic severity for UC errors in kernel context

2017-11-21T09:24:35Z

commit d65dfc81bb3894fdb68cbc74bbf5fb48d2354071 upstream. The AMD severity grading function was introduced in kernel 4.1. The current logic can possibly give MCE_AR_SEVERITY for uncorrectable errors in kernel context. The system may then get stuck in a loop as memory_failure() will try to handle the bad kernel memory and find it busy. Return MCE_PANIC_SEVERITY for all UC errors IN_KERNEL context on AMD systems. After: b2f9d678e28c ("x86/mce: Check for faults tagged in EXTABLE_CLASS_FAULT exception table entries") was accepted in v4.6, this issue was masked because of the tail-end attempt at kernel mode recovery in the #MC handler. However, uncorrectable errors IN_KERNEL context should always be considered unrecoverable and cause a panic. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Fixes: bf80bbd7dcf5 (x86/mce: Add an AMD severities-grading function) Link: http://lkml.kernel.org/r/20171106174633.13576-1-bp@alien8.de Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86/mcelog: Get rid of RCU remnants

2017-11-08T09:17:19Z

commit 7298f08ea8870d44d36c7d6cd07dd0303faef6c2 upstream. Jeremy reported a suspicious RCU usage warning in mcelog. /dev/mcelog is called in process context now as part of the notifier chain and doesn't need any of the fancy RCU and lockless accesses which it did in atomic context. Axe it all in favor of a simple mutex synchronization which cures the problem reported. Fixes: 5de97c9f6d85 ("x86/mce: Factor out and deprecate the /dev/mcelog driver") Reported-by: Jeremy Cline Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Reviewed-and-tested-by: Tony Luck Cc: Andi Kleen Cc: linux-edac@vger.kernel.org Cc: Laura Abbott Link: https://lkml.kernel.org/r/20171101164754.xzzmskl4ngrqc5br@pd.tnic Link: https://bugzilla.redhat.com/show_bug.cgi?id=1498969 Signed-off-by: Greg Kroah-Hartman

x86/mm, mm/hwpoison: Clear PRESENT bit for kernel 1:1 mappings of poison pages

2017-09-20T06:27:48Z

commit ce0fa3e56ad20f04d8252353dcd24e924abdafca upstream. Speculative processor accesses may reference any memory that has a valid page table entry. While a speculative access won't generate a machine check, it will log the error in a machine check bank. That could cause escalation of a subsequent error since the overflow bit will be then set in the machine check bank status register. Code has to be double-plus-tricky to avoid mentioning the 1:1 virtual address of the page we want to map out otherwise we may trigger the very problem we are trying to avoid. We use a non-canonical address that passes through the usual Linux table walking code to get to the same "pte". Thanks to Dave Hansen for reviewing several iterations of this. Also see: http://marc.info/?l=linux-mm&m=149860136413338&w=2 Signed-off-by: Tony Luck Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Dave Hansen Cc: Denys Vlasenko Cc: Elliott, Robert (Persistent Memory) Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Naoya Horiguchi Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20170816171803.28342-1-tony.luck@intel.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

x86: Constify attribute_group structures

2017-08-18T09:30:35Z

attribute_groups are not supposed to change at runtime and none of the groups is modified. Mark the non-const structs as const. [ tglx: Folded into one big patch ] Signed-off-by: Arvind Yadav Signed-off-by: Thomas Gleixner Cc: tony.luck@intel.com Cc: bp@alien8.de Link: http://lkml.kernel.org/r/1500550238-15655-2-git-send-email-arvind.yadav.cs@gmail.com

x86/mce: Always save severity in machine_check_poll()

2017-06-26T13:58:56Z

The MCE severity gives a hint as to how to handle the error. The notifier blocks can then use the severity to decide on an action. It's not necessary for machine_check_poll() to filter errors for the notifier chain, since each block will check its own set of conditions before handling an error. Also, there isn't any urgency for machine_check_poll() to make decisions based on severity like in do_machine_check(). If we can assume that a severity is set then we can use it in more notifier blocks. For example, the CEC block could check for a "KEEP" severity rather than checking bits in the status. This isn't possible now since the severity is not set except for "DEFFRRED/UCNA" errors with a valid address. Save the severity since we have it, and let the notifier blocks decide if they want to do anything. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Link: http://lkml.kernel.org/r/1498074402-98633-1-git-send-email-Yazen.Ghannam@amd.com

x86/MCE, xen/mcelog: Make /dev/mcelog registration messages more precise

2017-06-20T21:25:19Z

When running under Xen as dom0, /dev/mcelog is being provided by Xen instead of the normal mcelog character device of the MCE core. Convert an error message being issued by the MCE core in this case to an informative message that Xen has registered the device. Signed-off-by: Juergen Gross Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Cc: xen-devel@lists.xenproject.org Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20170614084059.19294-1-jgross@suse.com

x86/mce: Update bootlog description to reflect behavior on AMD

2017-06-14T05:32:10Z

The bootlog option is only disabled by default on AMD Fam10h and older systems. Update bootlog description to say this. Change the family value to hex to avoid confusion. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20170613162835.30750-9-bp@alien8.de Signed-off-by: Ingo Molnar

x86/mce: Don't disable MCA banks when offlining a CPU on AMD

2017-06-14T05:32:09Z

AMD systems have non-core, shared MCA banks within a die. These banks are controlled by a master CPU per die. If this CPU is offlined then all the shared banks are disabled in addition to the CPU's core banks. Also, Fam17h systems may have SMT enabled. The MCA_CTL register is shared between SMT thread siblings. If a CPU is offlined then all its sibling's MCA banks are also disabled. Extend the existing vendor check to AMD too. Signed-off-by: Yazen Ghannam [ Fix up comment. ] Signed-off-by: Borislav Petkov Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Cc: linux-edac Link: http://lkml.kernel.org/r/20170613162835.30750-8-bp@alien8.de Signed-off-by: Ingo Molnar

x86/mce/mce-inject: Preset the MCE injection struct

2017-06-14T05:32:09Z

Populate the MCE injection struct before doing initial injection so that values which don't change have sane defaults. Tested-by: Yazen Ghannam Signed-off-by: Borislav Petkov Acked-by: Yazen Ghannam Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Link: http://lkml.kernel.org/r/20170613162835.30750-7-bp@alien8.de Signed-off-by: Ingo Molnar

x86/mce: Clean up include files

2017-06-14T05:32:08Z

Not really needed. Tested-by: Yazen Ghannam Signed-off-by: Borislav Petkov Acked-by: Yazen Ghannam Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tony Luck Link: http://lkml.kernel.org/r/20170613162835.30750-6-bp@alien8.de Signed-off-by: Ingo Molnar