From: "Theodore Ts'o" Subject: [PATCH] e2fsck: Fix segmentation fault when checking a file system Date: Wed, 17 Mar 2010 13:48:12 -0400 Message-ID: To: linux-ext4@vger.kernel.org Return-path: Received: from thunk.org ([69.25.196.29]:46020 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754831Ab0CQRsz (ORCPT ); Wed, 17 Mar 2010 13:48:55 -0400 Sender: linux-ext4-owner@vger.kernel.org List-ID: Murphy's Law says that this report would come in *just* after I release 1.41.11. :-) - Ted >From 19f433a5214e720a95bdbf78bdcdca353c25b770 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Wed, 17 Mar 2010 13:32:52 -0400 Subject: [PATCH] e2fsck: Fix segmentation fault when checking a file system If a corrupted file system causes us to want to delete an extent, and that causes us to want to release a block in e2fsck pass #1, it would be preferable if e2fsck didn't seg fault. This tends to get users craky, as users are wont to do. :-) Thanks to Dirk Reiners for reporting this bug: e2fsck crashes fixing a corrupted 3.5 TB filesystem: 0x0000000000432002 in ext2fs_unmark_generic_bitmap (bitmap=0x0, bitno=623386749) at gen_bitmap.c:183 183 if ((bitno < bitmap->start) || (bitno > bitmap->end)) { (gdb) bt bitno=623386749) at gen_bitmap.c:183 block=623386749) at ../../lib/ext2fs/bitops.h:319 inuse=-1) at alloc_stats.c:78 extent.c:1509 pb=0x7fffffffdfe0, start_block=0, ehandle=0x6dcf50) at pass1.c:1709 pb=0x7fffffffdfe0, start_block=0, ehandle=0x6dcf50) at pass1.c:1737 pctx=0x7fffffffe100, pb=0x7fffffffdfe0) at pass1.c:1842 block_buf=0x6c4330 "\373\212#") at pass1.c:1920 The source of the NULL bitmap is fs on stack frame 2: (gdb) up 2 inuse=-1) at alloc_stats.c:78 78 ext2fs_unmark_block_bitmap(fs->block_map, blk); Addresses-SourceForge-Bug: #2971800 Signed-off-by: "Theodore Ts'o" --- e2fsck/pass1.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c index 130b3f6..3c6f91c 100644 --- a/e2fsck/pass1.c +++ b/e2fsck/pass1.c @@ -1706,6 +1706,7 @@ static void scan_extent_node(e2fsck_t ctx, struct problem_context *pctx, pctx->blk2 = extent.e_lblk; pctx->num = extent.e_len; if (fix_problem(ctx, problem, pctx)) { + e2fsck_read_bitmaps(ctx); pctx->errcode = ext2fs_extent_delete(ehandle, 0); if (pctx->errcode) { -- 1.6.6.1.1.g974db.dirty