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authorDan Williams <dan.j.williams@intel.com>2022-08-26 10:18:07 -0700
committerAndrew Morton <akpm@linux-foundation.org>2022-09-11 16:22:29 -0700
commit65d3440e8d2e9e024ef2357f8ff021611b068c99 (patch)
treeac49d5f6d958a1ada1a0012320ad9b56b8863c8e
parentfd63612ae81159bd7e59762de478889315463ee8 (diff)
mm/memory-failure: fix detection of memory_failure() handlers
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@dwillia2-xfh.jf.intel.com Fixes: 33a8f7f2b3a3 ("pagemap,pmem: introduce ->memory_failure()") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Shiyang Ruan <ruansy.fnst@fujitsu.com> Cc: Darrick J. Wong <djwong@kernel.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Dave Chinner <david@fromorbit.com> Cc: Goldwyn Rodrigues <rgoldwyn@suse.de> Cc: Jane Chu <jane.chu@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Ritesh Harjani <riteshh@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r--include/linux/memremap.h5
-rw-r--r--mm/memory-failure.c2
2 files changed, 6 insertions, 1 deletions
diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index 19010491a603..c3b4cc84877b 100644
--- a/include/linux/memremap.h
+++ b/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)
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 14439806b5ef..8a4294afbfa0 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1928,7 +1928,7 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
* 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