The patch titled
Subject: mm/memory-failure: fix detection of memory_failure() handlers
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-memory-failure-fix-detection-of-memory_failure-handlers.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memory-failure-fix-detection-of-memory_failure-handlers.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm/memory-failure: fix detection of memory_failure() handlers
Date: Fri, 26 Aug 2022 10:18:07 -0700
Some pagemap types, like MEMORY_DEVICE_GENERIC (device-dax) do not even
have pagemap ops which results in crash signatures like this:
BUG: kernel NULL pointer dereference, address: 0000000000000010
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 8000000205073067 P4D 8000000205073067 PUD 2062b3067 PMD 0
Oops: 0000 [#1] PREEMPT SMP PTI
CPU: 22 PID: 4535 Comm: device-dax Tainted: G OE N 6.0.0-rc2+ #59
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:memory_failure+0x667/0xba0
[..]
Call Trace:
<TASK>
? _printk+0x58/0x73
do_madvise.part.0.cold+0xaf/0xc5
Check for ops before checking if the ops have a memory_failure()
handler.
Link: https://lkml.kernel.org/r/166153428781.2758201.1990616683438224741.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 33a8f7f2b3a3 ("pagemap,pmem: introduce ->memory_failure()")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Darrick J. Wong <djwong@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Cc: Goldwyn Rodrigues <rgoldwyn@xxxxxxx>
Cc: Jane Chu <jane.chu@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Ritesh Harjani <riteshh@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memremap.h | 5 +++++
mm/memory-failure.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
--- a/include/linux/memremap.h~mm-memory-failure-fix-detection-of-memory_failure-handlers
+++ a/include/linux/memremap.h
@@ -139,6 +139,11 @@ struct dev_pagemap {
};
};
+static inline bool pgmap_has_memory_failure(struct dev_pagemap *pgmap)
+{
+ return pgmap->ops && pgmap->ops->memory_failure;
+}
+
static inline struct vmem_altmap *pgmap_altmap(struct dev_pagemap *pgmap)
{
if (pgmap->flags & PGMAP_ALTMAP_VALID)
--- a/mm/memory-failure.c~mm-memory-failure-fix-detection-of-memory_failure-handlers
+++ a/mm/memory-failure.c
@@ -1928,7 +1928,7 @@ static int memory_failure_dev_pagemap(un
* Call driver's implementation to handle the memory failure, otherwise
* fall back to generic handler.
*/
- if (pgmap->ops->memory_failure) {
+ if (pgmap_has_memory_failure(pgmap)) {
rc = pgmap->ops->memory_failure(pgmap, pfn, 1, flags);
/*
* Fall back to generic handler too if operation is not
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
xfs-quiet-notify_failure-eopnotsupp-cases.patch
xfs-fix-sb_born-check-in-xfs_dax_notify_failure.patch
mm-memory-failure-fix-detection-of-memory_failure-handlers.patch
mm-memory-failure-fall-back-to-vma_address-when-notify_failure-fails.patch
