From: ira.weiny@intel.com
To: Rik van Riel <riel@surriel.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>,
x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: [RFC PATCH 0/5] Print CPU at segfault time
Date: Fri, 5 Aug 2022 10:30:04 -0700 [thread overview]
Message-ID: <20220805173009.3128098-1-ira.weiny@intel.com> (raw)
From: Ira Weiny <ira.weiny@intel.com>
Rik reported that the knowledge of which CPU's are seeing faults can help in
determining which CPUs are failing in a large data center.[1]
Storing the CPU at exception entry time allows this print to report the CPU
which actually took the exception. This still may not be the CPU which is
failing but it should be closer.
Dave and Boris recognized that the auxiliary pt_regs work I did for the PKS
series could help to store this value and avoid passing the CPU throughout the
fault handler call stack.
I'm posting this RFC for a few reasons.
1) I've left in arch_restore_aux_pt_regs(). This is called on exception exit
and is not needed for this use case but I believe it is better to leave it
for symmetry within the generic entry code. This also means that patch
1/5 could be dropped completely.
2) I want to see if 0day has any issues with the Kconfig option changes I made
which may creep in from a 32bit build.
3) The final patch could be squashed with Rik's but it seemed better to leave
them split for authorship clarity.
Compile tested only.
[1] https://lore.kernel.org/all/20220805101644.2e674553@imladris.surriel.com/
Ira Weiny (4):
entry: Pass pt_regs to irqentry_exit_cond_resched()
entry: Add calls for save/restore auxiliary pt_regs
x86/entry: Add auxiliary pt_regs space
x86/entry: Store CPU info on exception entry
Rik van Riel (1):
x86,mm: print likely CPU at segfault time
arch/arm64/include/asm/preempt.h | 2 +-
arch/arm64/kernel/entry-common.c | 4 +--
arch/x86/Kconfig | 4 +++
arch/x86/entry/calling.h | 19 ++++++++++++++
arch/x86/entry/common.c | 2 +-
arch/x86/entry/entry_64.S | 22 ++++++++++++++++
arch/x86/entry/entry_64_compat.S | 6 +++++
arch/x86/include/asm/entry-common.h | 12 +++++++++
arch/x86/include/asm/ptrace.h | 19 ++++++++++++++
arch/x86/kernel/asm-offsets_64.c | 15 +++++++++++
arch/x86/kernel/head_64.S | 6 +++++
arch/x86/mm/fault.c | 10 ++++++++
include/linux/entry-common.h | 25 +++++++++++++-----
kernel/entry/common.c | 29 ++++++++++++++++-----
kernel/sched/core.c | 40 ++++++++++++++---------------
15 files changed, 178 insertions(+), 37 deletions(-)
base-commit: b2a88c212e652e94f1e4b635910972ac57ba4e97
--
2.35.3
next reply other threads:[~2022-08-05 17:30 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-05 17:30 ira.weiny [this message]
2022-08-05 17:30 ` [RFC PATCH 1/5] entry: Pass pt_regs to irqentry_exit_cond_resched() ira.weiny
2022-08-05 18:33 ` Rik van Riel
2022-08-08 10:38 ` Borislav Petkov
2022-08-08 17:34 ` Ira Weiny
2022-08-08 17:38 ` Borislav Petkov
2022-08-08 17:43 ` Dave Hansen
2022-08-08 17:52 ` Borislav Petkov
2022-08-09 23:18 ` Thomas Gleixner
2022-08-10 7:25 ` Thomas Gleixner
2022-08-05 17:30 ` [RFC PATCH 2/5] entry: Add calls for save/restore auxiliary pt_regs ira.weiny
2022-08-05 18:34 ` Rik van Riel
2022-08-09 12:05 ` Borislav Petkov
2022-08-09 18:38 ` Ira Weiny
2022-08-09 18:49 ` Borislav Petkov
2022-08-09 21:14 ` Thomas Gleixner
2022-08-09 21:38 ` Borislav Petkov
2022-08-09 22:33 ` Ira Weiny
2022-08-09 21:49 ` Ira Weiny
2022-08-09 23:53 ` Thomas Gleixner
2022-08-05 17:30 ` [RFC PATCH 3/5] x86/entry: Add auxiliary pt_regs space ira.weiny
2022-08-05 18:45 ` Rik van Riel
2022-08-05 17:30 ` [RFC PATCH 4/5] x86,mm: print likely CPU at segfault time ira.weiny
2022-08-05 17:30 ` [RFC PATCH 5/5] x86/entry: Store CPU info on exception entry ira.weiny
2022-08-05 18:46 ` Rik van Riel
2022-08-05 18:47 ` Dave Hansen
2022-08-06 9:01 ` Ingo Molnar
2022-08-06 9:11 ` Borislav Petkov
2022-08-07 10:02 ` Ingo Molnar
2022-08-07 10:35 ` Borislav Petkov
2022-08-07 20:02 ` Ira Weiny
2022-08-08 11:03 ` Ingo Molnar
2022-08-08 12:01 ` Borislav Petkov
2022-08-09 20:06 ` Thomas Gleixner
2022-08-08 16:16 ` Dave Hansen
2022-08-08 17:24 ` Rik van Riel
2022-08-09 21:19 ` Andy Lutomirski
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