linux-stable.git/arch/x86/kernel/cpu/mce, branch linux-5.4.y Linux kernel stable tree x86/mce/amd: Add default names for MCA banks and blocks 2025-08-28T14:21:34+00:00 Yazen Ghannam yazen.ghannam@amd.com 2025-07-23T04:24:51+00:00 3dbc0ed94799bf99eef2acd4b7551a790cae5803 [ Upstream commit d66e1e90b16055d2f0ee76e5384e3f119c3c2773 ] Ensure that sysfs init doesn't fail for new/unrecognized bank types or if a bank has additional blocks available. Most MCA banks have a single thresholding block, so the block takes the same name as the bank. Unified Memory Controllers (UMCs) are a special case where there are two blocks and each has a unique name. However, the microarchitecture allows for five blocks. Any new MCA bank types with more than one block will be missing names for the extra blocks. The MCE sysfs will fail to initialize in this case. Fixes: 87a6d4091bd7 ("x86/mce/AMD: Update sysfs bank names for SMCA systems") Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-3-236dd74f645f@amd.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit d66e1e90b16055d2f0ee76e5384e3f119c3c2773 ]

Ensure that sysfs init doesn't fail for new/unrecognized bank types or if
a bank has additional blocks available.

Most MCA banks have a single thresholding block, so the block takes the same
name as the bank.

Unified Memory Controllers (UMCs) are a special case where there are two
blocks and each has a unique name.

However, the microarchitecture allows for five blocks. Any new MCA bank types
with more than one block will be missing names for the extra blocks. The MCE
sysfs will fail to initialize in this case.

Fixes: 87a6d4091bd7 ("x86/mce/AMD: Update sysfs bank names for SMCA systems")
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-3-236dd74f645f@amd.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/mce: Make sure CMCI banks are cleared during shutdown on Intel 2025-07-17T16:25:02+00:00 JP Kobryn inwardvessel@gmail.com 2025-06-27T17:49:35+00:00 7c2bc303a035060c474aa931612c127cc5519c5b commit 30ad231a5029bfa16e46ce868497b1a5cdd3c24d upstream. CMCI banks are not cleared during shutdown on Intel CPUs. As a side effect, when a kexec is performed, CPUs coming back online are unable to rediscover/claim these occupied banks which breaks MCE reporting. Clear the CPU ownership during shutdown via cmci_clear() so the banks can be reclaimed and MCE reporting will become functional once more. [ bp: Massage commit message. ] Reported-by: Aijay Adams <aijay@meta.com> Signed-off-by: JP Kobryn <inwardvessel@gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Tony Luck <tony.luck@intel.com> Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> Cc: <stable@kernel.org> Link: https://lore.kernel.org/20250627174935.95194-1-inwardvessel@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 30ad231a5029bfa16e46ce868497b1a5cdd3c24d upstream.

CMCI banks are not cleared during shutdown on Intel CPUs. As a side effect,
when a kexec is performed, CPUs coming back online are unable to
rediscover/claim these occupied banks which breaks MCE reporting.

Clear the CPU ownership during shutdown via cmci_clear() so the banks can
be reclaimed and MCE reporting will become functional once more.

  [ bp: Massage commit message. ]

Reported-by: Aijay Adams <aijay@meta.com>
Signed-off-by: JP Kobryn <inwardvessel@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/20250627174935.95194-1-inwardvessel@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/mce: Don't remove sysfs if thresholding sysfs init fails 2025-07-17T16:25:02+00:00 Yazen Ghannam yazen.ghannam@amd.com 2025-06-24T14:15:56+00:00 d6720de3bdc1a55e16fafc0d9bd5e88fbd6c4f04 commit 4c113a5b28bfd589e2010b5fc8867578b0135ed7 upstream. Currently, the MCE subsystem sysfs interface will be removed if the thresholding sysfs interface fails to be created. A common failure is due to new MCA bank types that are not recognized and don't have a short name set. The MCA thresholding feature is optional and should not break the common MCE sysfs interface. Also, new MCA bank types are occasionally introduced, and updates will be needed to recognize them. But likewise, this should not break the common sysfs interface. Keep the MCE sysfs interface regardless of the status of the thresholding sysfs interface. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com> Reviewed-by: Tony Luck <tony.luck@intel.com> Tested-by: Tony Luck <tony.luck@intel.com> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-1-236dd74f645f@amd.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 4c113a5b28bfd589e2010b5fc8867578b0135ed7 upstream.

Currently, the MCE subsystem sysfs interface will be removed if the
thresholding sysfs interface fails to be created. A common failure is due to
new MCA bank types that are not recognized and don't have a short name set.

The MCA thresholding feature is optional and should not break the common MCE
sysfs interface. Also, new MCA bank types are occasionally introduced, and
updates will be needed to recognize them. But likewise, this should not break
the common sysfs interface.

Keep the MCE sysfs interface regardless of the status of the thresholding
sysfs interface.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-1-236dd74f645f@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/mce/amd: Fix threshold limit reset 2025-07-17T16:25:02+00:00 Yazen Ghannam yazen.ghannam@amd.com 2025-06-24T14:15:59+00:00 a3e80b2fcc50c89d8f4f17c644fbf5f505e8f6b6 commit 5f6e3b720694ad771911f637a51930f511427ce1 upstream. The MCA threshold limit must be reset after servicing the interrupt. Currently, the restart function doesn't have an explicit check for this. It makes some assumptions based on the current limit and what's in the registers. These assumptions don't always hold, so the limit won't be reset in some cases. Make the reset condition explicit. Either an interrupt/overflow has occurred or the bank is being initialized. Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-4-236dd74f645f@amd.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 5f6e3b720694ad771911f637a51930f511427ce1 upstream.

The MCA threshold limit must be reset after servicing the interrupt.

Currently, the restart function doesn't have an explicit check for this.  It
makes some assumptions based on the current limit and what's in the registers.
These assumptions don't always hold, so the limit won't be reset in some
cases.

Make the reset condition explicit. Either an interrupt/overflow has occurred
or the bank is being initialized.

Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/20250624-wip-mca-updates-v4-4-236dd74f645f@amd.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/mce: Make sure to grab mce_sysfs_mutex in set_bank() 2024-04-13T10:51:36+00:00 Borislav Petkov (AMD) bp@alien8.de 2024-03-13T13:48:27+00:00 976b1b2680fb4c01aaf05a0623288d87619a6c93 commit 3ddf944b32f88741c303f0b21459dbb3872b8bc5 upstream. Modifying a MCA bank's MCA_CTL bits which control which error types to be reported is done over /sys/devices/system/machinecheck/ ├── machinecheck0 │   ├── bank0 │   ├── bank1 │   ├── bank10 │   ├── bank11 ... sysfs nodes by writing the new bit mask of events to enable. When the write is accepted, the kernel deletes all current timers and reinits all banks. Doing that in parallel can lead to initializing a timer which is already armed and in the timer wheel, i.e., in use already: ODEBUG: init active (active state 0) object: ffff888063a28000 object type: timer_list hint: mce_timer_fn+0x0/0x240 arch/x86/kernel/cpu/mce/core.c:2642 WARNING: CPU: 0 PID: 8120 at lib/debugobjects.c:514 debug_print_object+0x1a0/0x2a0 lib/debugobjects.c:514 Fix that by grabbing the sysfs mutex as the rest of the MCA sysfs code does. Reported by: Yue Sun <samsun1006219@gmail.com> Reported by: xingwei lee <xrivendell7@gmail.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Cc: <stable@kernel.org> Link: https://lore.kernel.org/r/CAEkJfYNiENwQY8yV1LYJ9LjJs%2Bx_-PqMv98gKig55=2vbzffRw@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 3ddf944b32f88741c303f0b21459dbb3872b8bc5 upstream.

Modifying a MCA bank's MCA_CTL bits which control which error types to
be reported is done over

  /sys/devices/system/machinecheck/
  ├── machinecheck0
  │   ├── bank0
  │   ├── bank1
  │   ├── bank10
  │   ├── bank11
  ...

sysfs nodes by writing the new bit mask of events to enable.

When the write is accepted, the kernel deletes all current timers and
reinits all banks.

Doing that in parallel can lead to initializing a timer which is already
armed and in the timer wheel, i.e., in use already:

  ODEBUG: init active (active state 0) object: ffff888063a28000 object
  type: timer_list hint: mce_timer_fn+0x0/0x240 arch/x86/kernel/cpu/mce/core.c:2642
  WARNING: CPU: 0 PID: 8120 at lib/debugobjects.c:514
  debug_print_object+0x1a0/0x2a0 lib/debugobjects.c:514

Fix that by grabbing the sysfs mutex as the rest of the MCA sysfs code
does.

Reported by: Yue Sun <samsun1006219@gmail.com>
Reported by: xingwei lee <xrivendell7@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/CAEkJfYNiENwQY8yV1LYJ9LjJs%2Bx_-PqMv98gKig55=2vbzffRw@mail.gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86/mce: Mark fatal MCE's page as poison to avoid panic in the kdump kernel 2024-02-23T07:24:54+00:00 Zhiquan Li zhiquan1.li@intel.com 2023-10-26T00:39:03+00:00 980d5fe989e06e56af37a2fb5bf5d195b722192d [ Upstream commit 9f3b130048bfa2e44a8cfb1b616f826d9d5d8188 ] Memory errors don't happen very often, especially fatal ones. However, in large-scale scenarios such as data centers, that probability increases with the amount of machines present. When a fatal machine check happens, mce_panic() is called based on the severity grading of that error. The page containing the error is not marked as poison. However, when kexec is enabled, tools like makedumpfile understand when pages are marked as poison and do not touch them so as not to cause a fatal machine check exception again while dumping the previous kernel's memory. Therefore, mark the page containing the error as poisoned so that the kexec'ed kernel can avoid accessing the page. [ bp: Rewrite commit message and comment. ] Co-developed-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Youquan Song <youquan.song@intel.com> Signed-off-by: Zhiquan Li <zhiquan1.li@intel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Link: https://lore.kernel.org/r/20231014051754.3759099-1-zhiquan1.li@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 9f3b130048bfa2e44a8cfb1b616f826d9d5d8188 ]

Memory errors don't happen very often, especially fatal ones. However,
in large-scale scenarios such as data centers, that probability
increases with the amount of machines present.

When a fatal machine check happens, mce_panic() is called based on the
severity grading of that error. The page containing the error is not
marked as poison.

However, when kexec is enabled, tools like makedumpfile understand when
pages are marked as poison and do not touch them so as not to cause
a fatal machine check exception again while dumping the previous
kernel's memory.

Therefore, mark the page containing the error as poisoned so that the
kexec'ed kernel can avoid accessing the page.

  [ bp: Rewrite commit message and comment. ]

Co-developed-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Youquan Song <youquan.song@intel.com>
Signed-off-by: Zhiquan Li <zhiquan1.li@intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Link: https://lore.kernel.org/r/20231014051754.3759099-1-zhiquan1.li@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
x86/mce: Deduplicate exception handling 2022-07-29T15:14:18+00:00 Thomas Gleixner tglx@linutronix.de 2021-09-08T13:29:15+00:00 0a0fbbd6cb654f748d87c0db10c31741101f2ab2 [ Upstream commit e42404afc4ca856c48f1e05752541faa3587c472 ] Prepare code for further simplification. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20210908132525.096452100@linutronix.de Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit e42404afc4ca856c48f1e05752541faa3587c472 ]

Prepare code for further simplification. No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210908132525.096452100@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
x86/mce: Mark mce_read_aux() noinstr 2022-01-27T08:19:43+00:00 Borislav Petkov bp@suse.de 2021-11-02T10:14:48+00:00 fcd7e8ccc437e06ba3400c58d7c0210191e7b1ae [ Upstream commit db6c996d6ce45dfb44891f0824a65ecec216f47a ] Fixes vmlinux.o: warning: objtool: do_machine_check()+0x681: call to mce_read_aux() leaves .noinstr.text section Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211208111343.8130-10-bp@alien8.de Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit db6c996d6ce45dfb44891f0824a65ecec216f47a ]

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0x681: call to mce_read_aux() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-10-bp@alien8.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
x86/mce: Mark mce_end() noinstr 2022-01-27T08:19:43+00:00 Borislav Petkov bp@suse.de 2021-11-01T15:43:33+00:00 a0d171398dcd5df95476bce57d291c399b127b6e [ Upstream commit b4813539d37fa31fed62cdfab7bd2dd8929c5b2e ] It is called by the #MC handler which is noinstr. Fixes vmlinux.o: warning: objtool: do_machine_check()+0xbd6: call to memset() leaves .noinstr.text section Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211208111343.8130-9-bp@alien8.de Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit b4813539d37fa31fed62cdfab7bd2dd8929c5b2e ]

It is called by the #MC handler which is noinstr.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xbd6: call to memset() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-9-bp@alien8.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
x86/mce: Mark mce_panic() noinstr 2022-01-27T08:19:43+00:00 Borislav Petkov bp@suse.de 2021-11-01T12:39:35+00:00 bca5aa920274a1609c46a386d743c9d9bf214dcb [ Upstream commit 3c7ce80a818fa7950be123cac80cd078e5ac1013 ] And allow instrumentation inside it because it does calls to other facilities which will not be tagged noinstr. Fixes vmlinux.o: warning: objtool: do_machine_check()+0xc73: call to mce_panic() leaves .noinstr.text section Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lore.kernel.org/r/20211208111343.8130-8-bp@alien8.de Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 3c7ce80a818fa7950be123cac80cd078e5ac1013 ]

And allow instrumentation inside it because it does calls to other
facilities which will not be tagged noinstr.

Fixes

  vmlinux.o: warning: objtool: do_machine_check()+0xc73: call to mce_panic() leaves .noinstr.text section

Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211208111343.8130-8-bp@alien8.de
Signed-off-by: Sasha Levin <sashal@kernel.org>