This is a note to let you know that I've just added the patch titled
nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
to the 5.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 782e53d0c14420858dbf0f8f797973c150d3b6d7 Mon Sep 17 00:00:00 2001
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Date: Mon, 12 Jun 2023 11:14:56 +0900
Subject: nilfs2: prevent general protection fault in nilfs_clear_dirty_page()
From: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
commit 782e53d0c14420858dbf0f8f797973c150d3b6d7 upstream.
In a syzbot stress test that deliberately causes file system errors on
nilfs2 with a corrupted disk image, it has been reported that
nilfs_clear_dirty_page() called from nilfs_clear_dirty_pages() can cause a
general protection fault.
In nilfs_clear_dirty_pages(), when looking up dirty pages from the page
cache and calling nilfs_clear_dirty_page() for each dirty page/folio
retrieved, the back reference from the argument page to "mapping" may have
been changed to NULL (and possibly others). It is necessary to check this
after locking the page/folio.
So, fix this issue by not calling nilfs_clear_dirty_page() on a page/folio
after locking it in nilfs_clear_dirty_pages() if the back reference
"mapping" from the page/folio is different from the "mapping" that held
the page/folio just before.
Link: https://lkml.kernel.org/r/20230612021456.3682-1-konishi.ryusuke@xxxxxxxxx
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Reported-by: syzbot+53369d11851d8f26735c@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://lkml.kernel.org/r/000000000000da4f6b05eb9bf593@xxxxxxxxxx
Tested-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/page.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
--- a/fs/nilfs2/page.c
+++ b/fs/nilfs2/page.c
@@ -370,7 +370,15 @@ void nilfs_clear_dirty_pages(struct addr
struct page *page = pvec.pages[i];
lock_page(page);
- nilfs_clear_dirty_page(page, silent);
+
+ /*
+ * This page may have been removed from the address
+ * space by truncation or invalidation when the lock
+ * was acquired. Skip processing in that case.
+ */
+ if (likely(page->mapping == mapping))
+ nilfs_clear_dirty_page(page, silent);
+
unlock_page(page);
}
pagevec_release(&pvec);
Patches currently in stable-queue which might be from konishi.ryusuke@xxxxxxxxx are
queue-5.4/nilfs2-prevent-general-protection-fault-in-nilfs_clear_dirty_page.patch
queue-5.4/nilfs2-reject-devices-with-insufficient-block-count.patch
queue-5.4/nilfs2-fix-buffer-corruption-due-to-concurrent-device-reads.patch
