Alexey Dobriyan cf6e693212 loop: fix NULL dereference if mount fails ... Commit bb21488482 ("[PATCH] switch loop") started to pass NULL bdev to ioctl hook. Steps to reproduce: [boot with loop.max_part=1] [mount -o loop something so mount fails] BUG: unable to handle kernel NULL pointer dereference at 00000000000000b8 IP: [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30 PGD 0 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC last sysfs file: /sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:35/ACPI0003:00/power_supply/ACAD/online CPU 0 Modules linked in: zfs nvidia(P) [last unloaded: zfs] Pid: 15177, comm: mount Tainted: P 2.6.32-rc4-zfs #2 Satellite X200 RIP: 0010:[<ffffffff811486ee>] [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30 RSP: 0018:ffff88003b3d5bb8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 000000000000125f RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88003b3d5ce8 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 00007ffffffff000 R13: 0000000000000000 R14: ffff880071cef280 R15: 00000000000200da FS: 00007fd77cfe7740(0000) GS:ffff880001600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00000000000000b8 CR3: 0000000001001000 CR4: 00000000000026f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process mount (pid: 15177, threadinfo ffff88003b3d4000, task ffff88007572f920) Stack: ffff88003b3d5c38 ffffffff812f95f5 ffff88007eeb6600 0000000000000000 <0> 0000000000000000 ffff88003b3d5c18 ffffffff811547d9 ffff88001bf11ef0 <0> 7fffffffffffffff ffff88001bf11ee8 ffff88001bf11ef0 0000000000000000 Call Trace: [<ffffffff812f95f5>] ? schedule_timeout+0x1f5/0x250 [<ffffffff811547d9>] ? rb_insert_color+0x109/0x140 [<ffffffff812fb754>] ? _spin_unlock_irq+0x14/0x40 [<ffffffff812f84c6>] ? wait_for_common+0x66/0x170 [<ffffffff8105a280>] ? default_wake_function+0x0/0x10 [<ffffffff810f8258>] ioctl_by_bdev+0x38/0x50 [<ffffffff811d2481>] loop_clr_fd+0x1e1/0x210 [<ffffffff811d2522>] lo_release+0x72/0x80 [<ffffffff810f934c>] __blkdev_put+0x1ac/0x1d0 [<ffffffff810f937b>] blkdev_put+0xb/0x10 [<ffffffff810f93b9>] blkdev_close+0x39/0x60 [<ffffffff810ccef3>] __fput+0xd3/0x230 [<ffffffff810cd06d>] fput+0x1d/0x30 [<ffffffff810c9680>] filp_close+0x50/0x80 [<ffffffff81061f11>] put_files_struct+0x81/0x100 [<ffffffff81061fde>] exit_files+0x4e/0x60 [<ffffffff81063ec5>] do_exit+0x6b5/0x730 [<ffffffff8107b279>] ? up_read+0x9/0x10 [<ffffffff8104c86e>] ? do_page_fault+0x18e/0x2a0 [<ffffffff81063f81>] do_group_exit+0x41/0xc0 [<ffffffff81064012>] sys_exit_group+0x12/0x20 [<ffffffff81030deb>] system_call_fastpath+0x16/0x1b Code: f8 48 89 e5 48 81 ec 30 01 00 00 48 89 5d d8 4c 89 6d e8 4c 89 65 e0 4c 89 75 f0 4c 89 7d f8 48 89 bd e8 fe ff ff 49 89 cd 89 f3 <49> 8b 88 b8 00 00 00 81 fa 68 12 00 00 0f 84 57 05 00 00 0f 86 RIP [<ffffffff811486ee>] blkdev_ioctl+0x2e/0xa30 RSP <ffff88003b3d5bb8> CR2: 00000000000000b8 ---[ end trace c0b4d3c3118d1427 ]--- Fixing recursive fault but reboot is needed! Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2009-10-29 07:39:27 -07:00
..
aoe	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
paride	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
amiflop.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
ataflop.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
brd.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
cciss_cmd.h	cciss: Ignore stale commands after reboot	2009-07-03 21:06:45 +02:00
cciss_scsi.c	cciss: decode unit attention in SCSI error handling code	2009-06-09 05:47:44 +02:00
cciss_scsi.h	cciss: Fix cciss SCSI rescan code to better notice device changes	2008-10-09 08:56:18 +02:00
cciss.c	cciss: Add cciss_allow_hpsa module parameter	2009-10-13 09:18:22 +02:00
cciss.h	cciss: Dynamically allocate the drive_info_struct for each logical drive.	2009-10-01 21:15:45 +02:00
cpqarray.c	cpqarray: switch to seq_file	2009-10-01 21:15:40 +02:00
cpqarray.h
cryptoloop.c
DAC960.c	dac960: switch to seq_file	2009-10-01 21:15:40 +02:00
DAC960.h
floppy.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
hd.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
ida_cmd.h
ida_ioctl.h
Kconfig	osdblk: a Linux block device for OSD objects	2009-06-24 12:25:02 +03:00
loop.c	loop: fix NULL dereference if mount fails	2009-10-29 07:39:27 -07:00
Makefile	osdblk: a Linux block device for OSD objects	2009-06-24 12:25:02 +03:00
mg_disk.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
nbd.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
osdblk.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
pktcdvd.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
ps3disk.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
ps3vram.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
smart1,2.h
sunvdc.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
swim3.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial	2009-09-22 07:51:45 -07:00
swim_asm.S	m68k: mac - Add SWIM floppy support	2009-03-26 21:15:27 +01:00
swim.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
sx8.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
ub.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
umem.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
umem.h
viodasd.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
virtio_blk.c	virtio_blk: Revert serial number support	2009-10-22 16:39:30 +10:30
xd.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
xd.h	[PATCH] switch xd	2008-10-21 07:48:11 -04:00
xen-blkfront.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
xsysace.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00
z2ram.c	const: make block_device_operations const	2009-09-22 07:17:25 -07:00