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authorZheng Liu <wenqing.lz@taobao.com>2013-07-20 21:58:38 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-07-20 21:58:38 -0400
commite94bd3490f4ef342801cfc76b33d8baf9ccc9437 (patch)
tree9bb1c336e54f5931f24a76ccaa60b921816092bc
parent36231d255b8df9cb4698e9a3902c16067d5c1398 (diff)
downloadlinux-sh-e94bd3490f4ef342801cfc76b33d8baf9ccc9437.tar.gz
ext4: fix a BUG when opening a file with O_TMPFILE flag
When we try to open a file with O_TMPFILE flag, we will trigger a bug. The root cause is that in ext4_orphan_add() we check ->i_nlink == 0 and this check always fails because we set ->i_nlink = 1 in inode_init_always(). We can use the following program to trigger it: int main(int argc, char *argv[]) { int fd; fd = open(argv[1], O_TMPFILE, 0666); if (fd < 0) { perror("open "); return -1; } close(fd); return 0; } The oops message looks like this: kernel BUG at fs/ext4/namei.c:2572! invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC Modules linked in: dlci bridge stp hidp cmtp kernelcapi l2tp_ppp l2tp_netlink l2tp_core sctp libcrc32c rfcomm tun fuse nfnetli nk can_raw ipt_ULOG can_bcm x25 scsi_transport_iscsi ipx p8023 p8022 appletalk phonet psnap vmw_vsock_vmci_transport af_key vmw_vmci rose vsock atm can netrom ax25 af_rxrpc ir da pppoe pppox ppp_generic slhc bluetooth nfc rfkill rds caif_socket caif crc_ccitt af_802154 llc2 llc snd_hda_codec_realtek snd_hda_intel snd_hda_codec serio_raw snd_pcm pcsp kr edac_core snd_page_alloc snd_timer snd soundcore r8169 mii sr_mod cdrom pata_atiixp radeon backlight drm_kms_helper ttm CPU: 1 PID: 1812571 Comm: trinity-child2 Not tainted 3.11.0-rc1+ #12 Hardware name: Gigabyte Technology Co., Ltd. GA-MA78GM-S2H/GA-MA78GM-S2H, BIOS F12a 04/23/2010 task: ffff88007dfe69a0 ti: ffff88010f7b6000 task.ti: ffff88010f7b6000 RIP: 0010:[<ffffffff8125ce69>] [<ffffffff8125ce69>] ext4_orphan_add+0x299/0x2b0 RSP: 0018:ffff88010f7b7cf8 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff8800966d3020 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff88007dfe70b8 RDI: 0000000000000001 RBP: ffff88010f7b7d40 R08: ffff880126a3c4e0 R09: ffff88010f7b7ca0 R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801271fd668 R13: ffff8800966d2f78 R14: ffff88011d7089f0 R15: ffff88007dfe69a0 FS: 00007f70441a3740(0000) GS:ffff88012a800000(0000) knlGS:00000000f77c96c0 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000002834000 CR3: 0000000107964000 CR4: 00000000000007e0 DR0: 0000000000780000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Stack: 0000000000002000 00000020810b6dde 0000000000000000 ffff88011d46db00 ffff8800966d3020 ffff88011d7089f0 ffff88009c7f4c10 ffff88010f7b7f2c ffff88007dfe69a0 ffff88010f7b7da8 ffffffff8125cfac ffff880100000004 Call Trace: [<ffffffff8125cfac>] ext4_tmpfile+0x12c/0x180 [<ffffffff811cba78>] path_openat+0x238/0x700 [<ffffffff8100afc4>] ? native_sched_clock+0x24/0x80 [<ffffffff811cc647>] do_filp_open+0x47/0xa0 [<ffffffff811db73f>] ? __alloc_fd+0xaf/0x200 [<ffffffff811ba2e4>] do_sys_open+0x124/0x210 [<ffffffff81010725>] ? syscall_trace_enter+0x25/0x290 [<ffffffff811ba3ee>] SyS_open+0x1e/0x20 [<ffffffff816ca8d4>] tracesys+0xdd/0xe2 [<ffffffff81001001>] ? start_thread_common.constprop.6+0x1/0xa0 Code: 04 00 00 00 89 04 24 31 c0 e8 c4 77 04 00 e9 43 fe ff ff 66 25 00 d0 66 3d 00 80 0f 84 0e fe ff ff 83 7b 48 00 0f 84 04 fe ff ff <0f> 0b 49 8b 8c 24 50 07 00 00 e9 88 fe ff ff 0f 1f 84 00 00 00 Here we couldn't call clear_nlink() directly because in d_tmpfile() we will call inode_dec_link_count() to decrease ->i_nlink. So this commit tries to call d_tmpfile() before ext4_orphan_add() to fix this problem. Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Zheng Liu <wenqing.lz@taobao.com> Tested-by: Darrick J. Wong <darrick.wong@oracle.com> Tested-by: Dave Jones <davej@redhat.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Acked-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/ext4/namei.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 234b834d5a97..35f55a0dbc4b 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -2316,11 +2316,11 @@ retry:
inode->i_op = &ext4_file_inode_operations;
inode->i_fop = &ext4_file_operations;
ext4_set_aops(inode);
+ d_tmpfile(dentry, inode);
err = ext4_orphan_add(handle, inode);
if (err)
goto err_drop_inode;
mark_inode_dirty(inode);
- d_tmpfile(dentry, inode);
unlock_new_inode(inode);
}
if (handle)