linux-kernel - [f2fs-dev] [PATCH v3 2/2] f2fs: fix infinite loop in __insert_extent

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Message-ID: <20250917023622.516052-2-wangzijie1@honor.com>
Date: Wed, 17 Sep 2025 10:36:22 +0800
From: wangzijie <wangzijie1@...or.com>
To: <jaegeuk@...nel.org>, <chao@...nel.org>
CC: <linux-f2fs-devel@...ts.sourceforge.net>, <linux-kernel@...r.kernel.org>,
	<bintian.wang@...or.com>, <feng.han@...or.com>, wangzijie
	<wangzijie1@...or.com>
Subject: [f2fs-dev] [PATCH v3 2/2] f2fs: fix infinite loop in __insert_extent_tree()

When we get wrong extent info data, and look up extent_node in rb tree,
it will cause infinite loop (CONFIG_F2FS_CHECK_FS=n). Avoiding this by
return NULL and print some kernel messages in that case.

Signed-off-by: wangzijie <wangzijie1@...or.com>
---
v3:
- followed by Jaegeuk's suggestion to print some kernel messages 
---
 fs/f2fs/extent_cache.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index 199c1e7a8..ba0a07bfd 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -604,7 +604,13 @@ static struct extent_node *__insert_extent_tree(struct f2fs_sb_info *sbi,
 			p = &(*p)->rb_right;
 			leftmost = false;
 		} else {
+			f2fs_err_ratelimited(sbi, "%s: corrupted extent, type: %d, "
+				"extent node in rb tree [%u, %u, %u], age [%llu, %llu], "
+				"extent node to insert [%u, %u, %u], age [%llu, %llu]",
+				__func__, et->type, en->ei.fofs, en->ei.blk, en->ei.len, en->ei.age,
+				en->ei.last_blocks, ei->fofs, ei->blk, ei->len, ei->age, ei->last_blocks);
 			f2fs_bug_on(sbi, 1);
+			return NULL;
 		}
 	}
 
-- 
2.25.1