From: Azat Khuzhin Subject: [PATCH] ext4: fix ext4_count_free_clusters() with EXT4FS_DEBUG and bigalloc enabled Date: Mon, 14 Apr 2014 20:18:36 +0400 Message-ID: <1397492316-12237-1-git-send-email-a3at.mail@gmail.com> Cc: Azat Khuzhin , "Theodore Ts'o" , Andreas Dilger , linux-kernel@vger.kernel.org (open list) To: linux-ext4@vger.kernel.org Return-path: Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org With bigalloc enabled we must use EXT4_CLUSTERS_PER_GROUP() instead of EXT4_BLOCKS_PER_GROUP() otherwise we will go beyond the allocated buffer. $ mount -t ext4 /dev/vde /vde [ 70.573993] EXT4-fs DEBUG (fs/ext4/mballoc.c, 2346): ext4_mb_alloc_groupinfo: [ 70.575174] allocated s_groupinfo array for 1 meta_bg's [ 70.576172] EXT4-fs DEBUG (fs/ext4/super.c, 2092): ext4_check_descriptors: [ 70.576972] Checking group descriptorsBUG: unable to handle kernel paging request at ffff88006ab56000 [ 72.463686] IP: [] __bitmap_weight+0x2a/0x7f [ 72.464168] PGD 295e067 PUD 2961067 PMD 7fa8e067 PTE 800000006ab56060 [ 72.464738] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC [ 72.465139] Modules linked in: [ 72.465402] CPU: 1 PID: 3560 Comm: mount Tainted: G W 3.14.0-rc2-00069-ge57bce1 #60 [ 72.466079] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 72.466505] task: ffff88007ce6c8a0 ti: ffff88006b7f0000 task.ti: ffff88006b7f0000 [ 72.466505] RIP: 0010:[] [] __bitmap_weight+0x2a/0x7f [ 72.466505] RSP: 0018:ffff88006b7f1c00 EFLAGS: 00010206 [ 72.466505] RAX: 0000000000000000 RBX: 000000000000050a RCX: 0000000000000040 [ 72.466505] RDX: 0000000000000000 RSI: 0000000000080000 RDI: 0000000000000000 [ 72.466505] RBP: ffff88006b7f1c28 R08: 0000000000000002 R09: 0000000000000000 [ 72.466505] R10: 000000000000babe R11: 0000000000000400 R12: 0000000000080000 [ 72.466505] R13: 0000000000000200 R14: 0000000000002000 R15: ffff88006ab55000 [ 72.466505] FS: 00007f43ba1fa840(0000) GS:ffff88007f800000(0000) knlGS:0000000000000000 [ 72.466505] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 72.466505] CR2: ffff88006ab56000 CR3: 000000006b7e6000 CR4: 00000000000006e0 [ 72.466505] Stack: [ 72.466505] ffff88006ab65000 0000000000000000 0000000000000000 0000000000010000 [ 72.466505] ffff88006ab6f400 ffff88006b7f1c58 ffffffff81396bb8 0000000000010000 [ 72.466505] 0000000000000000 ffff88007b869a90 ffff88006a48a000 ffff88006b7f1c70 [ 72.466505] Call Trace: [ 72.466505] [] memweight+0x5f/0x8a [ 72.466505] [] ext4_count_free+0x13/0x21 [ 72.466505] [] ext4_count_free_clusters+0xdb/0x171 [ 72.466505] [] ext4_fill_super+0x117c/0x28ef [ 72.466505] [] ? vsnprintf+0x1c7/0x3f7 [ 72.466505] [] mount_bdev+0x145/0x19c [ 72.466505] [] ? ext4_calculate_overhead+0x2a1/0x2a1 [ 72.466505] [] ext4_mount+0x15/0x17 [ 72.466505] [] mount_fs+0x67/0x150 [ 72.466505] [] vfs_kern_mount+0x64/0xde [ 72.466505] [] do_mount+0x6fe/0x7f5 [ 72.466505] [] ? strndup_user+0x3a/0xd9 [ 72.466505] [] SyS_mount+0x85/0xbe [ 72.466505] [] tracesys+0xdd/0xe2 [ 72.466505] Code: c3 89 f0 b9 40 00 00 00 55 99 48 89 e5 41 57 f7 f9 41 56 49 89 ff 41 55 45 31 ed 41 54 41 89 f4 53 31 db 41 89 c6 45 39 ee 7e 10 <4b> 8b 3c ef 49 ff c5 e8 bf ff ff ff 01 c3 eb eb 31 c0 45 85 f6 [ 72.466505] RIP [] __bitmap_weight+0x2a/0x7f [ 72.466505] RSP [ 72.466505] CR2: ffff88006ab56000 [ 72.466505] ---[ end trace 7d051a08ae138573 ]--- Killed --- fs/ext4/balloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 6ea7b14..5c56785 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -667,7 +667,7 @@ ext4_fsblk_t ext4_count_free_clusters(struct super_block *sb) continue; x = ext4_count_free(bitmap_bh->b_data, - EXT4_BLOCKS_PER_GROUP(sb) / 8); + EXT4_CLUSTERS_PER_GROUP(sb) / 8); printk(KERN_DEBUG "group %u: stored = %d, counted = %u\n", i, ext4_free_group_clusters(sb, gdp), x); bitmap_count += x; -- 1.9.1