The patch titled
Subject: x86/mce: collect error message for severities below MCE_PANIC_SEVERITY
has been added to the -mm mm-unstable branch. Its filename is
x86-mce-collect-error-message-for-severities-below-mce_panic_severity.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/x86-mce-collect-error-message-for-severities-below-mce_panic_severity.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx>
Subject: x86/mce: collect error message for severities below MCE_PANIC_SEVERITY
Date: Mon, 17 Feb 2025 14:33:31 +0800
Patch series "mm/hwpoison: Fix regressions in memory failure handling", v2.
This series addresses three regressions identified in memory failure
handling, as discovered using ras-tools[1]:
- `./einj_mem_uc copyin -f`
- `./einj_mem_uc futex -f`
- `./einj_mem_uc instr`
The regressions in the copyin and futex cases were caused by the
replacement of `EX_TYPE_UACCESS` with `EX_TYPE_EFAULT_REG` in some
copy-from-user operations, leading to kernel panics. The instr case
regression resulted from the PTE entry not being marked as hwpoison,
causing the system to send unnecessary SIGBUS signals.
These fixes ensure proper handling of memory errors and prevent kernel
panics and unnecessary signal dispatch.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/aegl/ras-tools.git
This patch (of 5):
Currently, mce_no_way_out() only collects error messages when the error
severity is equal to `MCE_PANIC_SEVERITY`. To improve diagnostics, modify
the behavior to also collect error messages when the severity is less than
`MCE_PANIC_SEVERITY`.
Link: https://lkml.kernel.org/r/20250217063335.22257-1-xueshuai@xxxxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/20250217063335.22257-2-xueshuai@xxxxxxxxxxxxxxxxx
Signed-off-by: Shuai Xue <xueshuai@xxxxxxxxxxxxxxxxx>
Cc: Acked-by:Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Borislav Betkov <bp@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: linmiaohe <linmiaohe@xxxxxxxxxx>
Cc: "Luck, Tony" <tony.luck@xxxxxxxxx>
Cc: Naoya Horiguchi <nao.horiguchi@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ruidong Tian <tianruidong@xxxxxxxxxxxxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: Jarkko Sakkinen <jarkko@xxxxxxxxxx>
Cc: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Cc: Yazen Ghannam <yazen.ghannam@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/mce/core.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
--- a/arch/x86/kernel/cpu/mce/core.c~x86-mce-collect-error-message-for-severities-below-mce_panic_severity
+++ a/arch/x86/kernel/cpu/mce/core.c
@@ -925,12 +925,13 @@ static __always_inline void quirk_zen_if
* Do a quick check if any of the events requires a panic.
* This decides if we keep the events around or clear them.
*/
-static __always_inline int mce_no_way_out(struct mce_hw_err *err, char **msg, unsigned long *validp,
- struct pt_regs *regs)
+static __always_inline bool mce_no_way_out(struct mce_hw_err *err, char **msg,
+ unsigned long *validp,
+ struct pt_regs *regs)
{
struct mce *m = &err->m;
char *tmp = *msg;
- int i;
+ int i, cur_sev = MCE_NO_SEVERITY, sev;
for (i = 0; i < this_cpu_read(mce_num_banks); i++) {
m->status = mce_rdmsrl(mca_msr_reg(i, MCA_STATUS));
@@ -945,13 +946,17 @@ static __always_inline int mce_no_way_ou
quirk_zen_ifu(i, m, regs);
m->bank = i;
- if (mce_severity(m, regs, &tmp, true) >= MCE_PANIC_SEVERITY) {
+ sev = mce_severity(m, regs, &tmp, true);
+ if (sev >= cur_sev) {
mce_read_aux(err, i);
*msg = tmp;
- return 1;
+ cur_sev = sev;
}
+
+ if (cur_sev == MCE_PANIC_SEVERITY)
+ return true;
}
- return 0;
+ return false;
}
/*
_
Patches currently in -mm which might be from xueshuai@xxxxxxxxxxxxxxxxx are
x86-mce-collect-error-message-for-severities-below-mce_panic_severity.patch
x86-mce-dump-error-msg-from-severities.patch
x86-mce-add-ex_type_efault_reg-as-in-kernel-recovery-context-to-fix-copy-from-user-operations-regression.patch
mm-hwpoison-fix-incorrect-not-recovered-report-for-recovered-clean-pages.patch
mm-memory-failure-move-return-value-documentation-to-function-declaration.patch
