The patch titled
Subject: mm/memory-failure: fall back to vma_address() when ->notify_failure() fails
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-memory-failure-fall-back-to-vma_address-when-notify_failure-fails.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-fall-back-to-vma_address-when-notify_failure-fails.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm/memory-failure: fall back to vma_address() when ->notify_failure() fails
Date: Fri, 26 Aug 2022 10:18:14 -0700
In the case where a filesystem is polled to take over the memory failure
and receives -EOPNOTSUPP it indicates that page->index and page->mapping
are valid for reverse mapping the failure address. Introduce
FSDAX_INVALID_PGOFF to distinguish when add_to_kill() is being called from
mf_dax_kill_procs() by a filesytem vs the typical memory_failure() path.
Otherwise, vma_pgoff_address() is called with an invalid fsdax_pgoff which
then trips this failing signature:
kernel BUG at mm/memory-failure.c:319!
invalid opcode: 0000 [#1] PREEMPT SMP PTI
CPU: 13 PID: 1262 Comm: dax-pmd Tainted: G OE N 6.0.0-rc2+ #62
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
RIP: 0010:add_to_kill.cold+0x19d/0x209
[..]
Call Trace:
<TASK>
collect_procs.part.0+0x2c4/0x460
memory_failure+0x71b/0xba0
? _printk+0x58/0x73
do_madvise.part.0.cold+0xaf/0xc5
Link: https://lkml.kernel.org/r/166153429427.2758201.14605968329933175594.stgit@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: c36e20249571 ("mm: introduce mf_dax_kill_procs() for fsdax case")
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>
---
mm/memory-failure.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
--- a/mm/memory-failure.c~mm-memory-failure-fall-back-to-vma_address-when-notify_failure-fails
+++ a/mm/memory-failure.c
@@ -345,13 +345,17 @@ static unsigned long dev_pagemap_mapping
* not much we can do. We just print a message and ignore otherwise.
*/
+#define FSDAX_INVALID_PGOFF ULONG_MAX
+
/*
* Schedule a process for later kill.
* Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
*
- * Notice: @fsdax_pgoff is used only when @p is a fsdax page.
- * In other cases, such as anonymous and file-backend page, the address to be
- * killed can be caculated by @p itself.
+ * Note: @fsdax_pgoff is used only when @p is a fsdax page and a
+ * filesystem with a memory failure handler has claimed the
+ * memory_failure event. In all other cases, page->index and
+ * page->mapping are sufficient for mapping the page back to its
+ * corresponding user virtual address.
*/
static void add_to_kill(struct task_struct *tsk, struct page *p,
pgoff_t fsdax_pgoff, struct vm_area_struct *vma,
@@ -367,11 +371,7 @@ static void add_to_kill(struct task_stru
tk->addr = page_address_in_vma(p, vma);
if (is_zone_device_page(p)) {
- /*
- * Since page->mapping is not used for fsdax, we need
- * calculate the address based on the vma.
- */
- if (p->pgmap->type == MEMORY_DEVICE_FS_DAX)
+ if (fsdax_pgoff != FSDAX_INVALID_PGOFF)
tk->addr = vma_pgoff_address(fsdax_pgoff, 1, vma);
tk->size_shift = dev_pagemap_mapping_shift(vma, tk->addr);
} else
@@ -523,7 +523,8 @@ static void collect_procs_anon(struct pa
if (!page_mapped_in_vma(page, vma))
continue;
if (vma->vm_mm == t->mm)
- add_to_kill(t, page, 0, vma, to_kill);
+ add_to_kill(t, page, FSDAX_INVALID_PGOFF, vma,
+ to_kill);
}
}
read_unlock(&tasklist_lock);
@@ -559,7 +560,8 @@ static void collect_procs_file(struct pa
* to be informed of all such data corruptions.
*/
if (vma->vm_mm == t->mm)
- add_to_kill(t, page, 0, vma, to_kill);
+ add_to_kill(t, page, FSDAX_INVALID_PGOFF, vma,
+ to_kill);
}
}
read_unlock(&tasklist_lock);
_
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
