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From: Eryu Guan <guaneryu@gmail.com>
To: linux-btrfs@vger.kernel.org
Cc: Eryu Guan <guaneryu@gmail.com>
Subject: [PATCH v2] btrfs-progs: fix segfault when listing column OTIME on big endian host
Date: Thu, 25 Jul 2013 22:12:01 +0800	[thread overview]
Message-ID: <1374761521-17603-1-git-send-email-guaneryu@gmail.com> (raw)
In-Reply-To: <51F10A50.9010308@cn.fujitsu.com>

The second btrfs command segfaults on big endian host(ppc64)

	btrfs subvolume snapshot /mnt/btrfs /mnt/btrfs/snap
	btrfs subvolume list -s /mnt/btrfs

And ltrace shows

	localtime(0x10029c482d0)                 = 0
	strftime( <no return ...>
	--- SIGSEGV (Segmentation fault) ---

The corresponding code

btrfs-list.c:
        case BTRFS_LIST_OTIME:
                if (subv->otime)
                        strftime(tstr, 256, "%Y-%m-%d %X",
                                 localtime(&subv->otime));
                else
                        strcpy(tstr, "-");
                printf("%s", tstr);
                break;

localtime() returned NULL then strftime() got SIGSEGV.

The reason is that ri->otime.sec is stored as little endian but
assigned to 't' without conversion.

Signed-off-by: Eryu Guan <guaneryu@gmail.com>
---
v1->v2:
  use btrfs_stack_timespec_sec() instead of raw convert.
  Thanks Miao Xie <miaox@cn.fujitsu.com> for pointing this out.

 btrfs-list.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/btrfs-list.c b/btrfs-list.c
index 4fab858..9deddd5 100644
--- a/btrfs-list.c
+++ b/btrfs-list.c
@@ -1052,7 +1052,7 @@ static int __list_subvol_search(int fd, struct root_lookup *root_lookup)
 				flags = btrfs_root_flags(ri);
 				if(sh.len >
 				   sizeof(struct btrfs_root_item_v0)) {
-					t = ri->otime.sec;
+					t = btrfs_stack_timespec_sec(&ri->otime);
 					ogen = btrfs_root_otransid(ri);
 					memcpy(uuid, ri->uuid, BTRFS_UUID_SIZE);
 					memcpy(puuid, ri->parent_uuid, BTRFS_UUID_SIZE);
-- 
1.8.3.1


  reply	other threads:[~2013-07-25 14:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-25  9:32 [PATCH] btrfs-progs: fix segfault when listing column OTIME on big endian host Eryu Guan
2013-07-25 11:21 ` Miao Xie
2013-07-25 14:12   ` Eryu Guan [this message]
2013-07-25 21:25     ` [PATCH v2] " Zach Brown
2013-07-26  4:34       ` Eryu Guan
2013-08-01 21:08     ` David Sterba

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