Commit 61fbae2b authored Feb 24, 2020 by Chao Yu Committed by Jaegeuk Kim Feb 27, 2020

f2fs: fix to avoid NULL pointer dereference



Unable to handle kernel NULL pointer dereference at virtual address 00000000
PC is at f2fs_free_dic+0x60/0x2c8
LR is at f2fs_decompress_pages+0x3c4/0x3e8
f2fs_free_dic+0x60/0x2c8
f2fs_decompress_pages+0x3c4/0x3e8
__read_end_io+0x78/0x19c
f2fs_post_read_work+0x6c/0x94
process_one_work+0x210/0x48c
worker_thread+0x2e8/0x44c
kthread+0x110/0x120
ret_from_fork+0x10/0x18

In f2fs_free_dic(), we can not use f2fs_put_page(,1) to release dic->tpages[i],
as the page's mapping is NULL.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

parent 7fa6d598

fs/f2fs/compress.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1137,7 +1137,8 @@ void f2fs_free_dic(struct decompress_io_ctx *dic)
		for (i = 0; i < dic->cluster_size; i++) {
		if (dic->rpages[i])
		continue;
		f2fs_put_page(dic->tpages[i], 1);
		unlock_page(dic->tpages[i]);
		put_page(dic->tpages[i]);
		}
		kfree(dic->tpages);
		}

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