Messages in this thread Patch in this message | | | Date | Tue, 2 Apr 2013 18:27:00 +0530 (IST) | From | P J P <> | Subject | [PATCH] To add NULL pointer check |
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Hello,
Commit - fa9150a84c - replaces a call to generic_writepages() in f2fs_write_data_pages() with write_cache_pages(), with a function pointer argument pointing to routine: __f2fs_writepage.
-> https://git.kernel.org/linus/fa9150a84ca333f68127097c4fa1eda4b3913a22
The patch below adds a NULL pointer check, from generic_writepages(), to avoid a possible NULL pointer dereference, in case if - mapping->a_ops->writepage - is NULL.
=== $ git diff diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c index 7bd22a2..9841372 100644 --- a/fs/f2fs/data.c +++ b/fs/f2fs/data.c @@ -550,9 +550,16 @@ redirty_out: static int __f2fs_writepage(struct page *page, struct writeback_control *wbc, void *data) { + int ret = 0; struct address_space *mapping = data; - int ret = mapping->a_ops->writepage(page, wbc); + + /* deal with chardevs and other special file */ + if (!mapping->a_ops->writepage) + return ret; + + ret = mapping->a_ops->writepage(page, wbc); mapping_set_error(mapping, ret); + return ret; } ===
Thank you. -- Prasad J Pandit / Red Hat Security Response Team DB7A 84C5 D3F9 7CD1 B5EB C939 D048 7860 3655 602B
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