android_kernel_samsung_msm8976/drivers
Seymour, Shane M bdedc624e9 st: null pointer dereference panic caused by use after kref_put by st_open
commit e7ac6c6666bec0a354758a1298d3231e4a635362 upstream.

Two SLES11 SP3 servers encountered similar crashes simultaneously
following some kind of SAN/tape target issue:

...
qla2xxx [0000:81:00.0]-801c:3: Abort command issued nexus=3:0:2 --  1 2002.
qla2xxx [0000:81:00.0]-801c:3: Abort command issued nexus=3:0:2 --  1 2002.
qla2xxx [0000:81:00.0]-8009:3: DEVICE RESET ISSUED nexus=3:0:2 cmd=ffff882f89c2c7c0.
qla2xxx [0000:81:00.0]-800c:3: do_reset failed for cmd=ffff882f89c2c7c0.
qla2xxx [0000:81:00.0]-800f:3: DEVICE RESET FAILED: Task management failed nexus=3:0:2 cmd=ffff882f89c2c7c0.
qla2xxx [0000:81:00.0]-8009:3: TARGET RESET ISSUED nexus=3:0:2 cmd=ffff882f89c2c7c0.
qla2xxx [0000:81:00.0]-800c:3: do_reset failed for cmd=ffff882f89c2c7c0.
qla2xxx [0000:81:00.0]-800f:3: TARGET RESET FAILED: Task management failed nexus=3:0:2 cmd=ffff882f89c2c7c0.
qla2xxx [0000:81:00.0]-8012:3: BUS RESET ISSUED nexus=3:0:2.
qla2xxx [0000:81:00.0]-802b:3: BUS RESET SUCCEEDED nexus=3:0:2.
qla2xxx [0000:81:00.0]-505f:3: Link is operational (8 Gbps).
qla2xxx [0000:81:00.0]-8018:3: ADAPTER RESET ISSUED nexus=3:0:2.
qla2xxx [0000:81:00.0]-00af:3: Performing ISP error recovery - ha=ffff88bf04d18000.
 rport-3:0-0: blocked FC remote port time out: removing target and saving binding
qla2xxx [0000:81:00.0]-505f:3: Link is operational (8 Gbps).
qla2xxx [0000:81:00.0]-8017:3: ADAPTER RESET SUCCEEDED nexus=3:0:2.
 rport-2:0-0: blocked FC remote port time out: removing target and saving binding
sg_rq_end_io: device detached
BUG: unable to handle kernel NULL pointer dereference at 00000000000002a8
IP: [<ffffffff8133b268>] __pm_runtime_idle+0x28/0x90
PGD 7e6586f067 PUD 7e5af06067 PMD 0 [1739975.390354] Oops: 0002 [#1] SMP
CPU 0
...
Supported: No, Proprietary modules are loaded [1739975.390463]
Pid: 27965, comm: ABCD Tainted: PF           X 3.0.101-0.29-default #1 HP ProLiant DL580 Gen8
RIP: 0010:[<ffffffff8133b268>]  [<ffffffff8133b268>] __pm_runtime_idle+0x28/0x90
RSP: 0018:ffff8839dc1e7c68  EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffff883f0592fc00 RCX: 0000000000000090
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000138
RBP: 0000000000000138 R08: 0000000000000010 R09: ffffffff81bd39d0
R10: 00000000000009c0 R11: ffffffff81025790 R12: 0000000000000001
R13: ffff883022212b80 R14: 0000000000000004 R15: ffff883022212b80
FS:  00007f8e54560720(0000) GS:ffff88407f800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00000000000002a8 CR3: 0000007e6ced6000 CR4: 00000000001407f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process ABCD (pid: 27965, threadinfo ffff8839dc1e6000, task ffff883592e0c640)
Stack:
 ffff883f0592fc00 00000000fffffffa 0000000000000001 ffff883022212b80
 ffff883eff772400 ffffffffa03fa309 0000000000000000 0000000000000000
 ffffffffa04003a0 ffff883f063196c0 ffff887f0379a930 ffffffff8115ea1e
Call Trace:
 [<ffffffffa03fa309>] st_open+0x129/0x240 [st]
 [<ffffffff8115ea1e>] chrdev_open+0x13e/0x200
 [<ffffffff811588a8>] __dentry_open+0x198/0x310
 [<ffffffff81167d74>] do_last+0x1f4/0x800
 [<ffffffff81168fe9>] path_openat+0xd9/0x420
 [<ffffffff8116946c>] do_filp_open+0x4c/0xc0
 [<ffffffff8115a00f>] do_sys_open+0x17f/0x250
 [<ffffffff81468d92>] system_call_fastpath+0x16/0x1b
 [<00007f8e4f617fd0>] 0x7f8e4f617fcf
Code: eb d3 90 48 83 ec 28 40 f6 c6 04 48 89 6c 24 08 4c 89 74 24 20 48 89 fd 48 89 1c 24 4c 89 64 24 10 41 89 f6 4c 89 6c 24 18 74 11 <f0> ff 8f 70 01 00 00 0f 94 c0 45 31 ed 84 c0 74 2b 4c 8d a5 a0
RIP  [<ffffffff8133b268>] __pm_runtime_idle+0x28/0x90
 RSP <ffff8839dc1e7c68>
CR2: 00000000000002a8

Analysis reveals the cause of the crash to be due to STp->device
being NULL. The pointer was NULLed via scsi_tape_put(STp) when it
calls scsi_tape_release(). In st_open() we jump to err_out after
scsi_block_when_processing_errors() completes and returns the
device as offline (sdev_state was SDEV_DEL):

1180 /* Open the device. Needs to take the BKL only because of incrementing the SCSI host
1181    module count. */
1182 static int st_open(struct inode *inode, struct file *filp)
1183 {
1184         int i, retval = (-EIO);
1185         int resumed = 0;
1186         struct scsi_tape *STp;
1187         struct st_partstat *STps;
1188         int dev = TAPE_NR(inode);
1189         char *name;
...
1217         if (scsi_autopm_get_device(STp->device) < 0) {
1218                 retval = -EIO;
1219                 goto err_out;
1220         }
1221         resumed = 1;
1222         if (!scsi_block_when_processing_errors(STp->device)) {
1223                 retval = (-ENXIO);
1224                 goto err_out;
1225         }
...
1264  err_out:
1265         normalize_buffer(STp->buffer);
1266         spin_lock(&st_use_lock);
1267         STp->in_use = 0;
1268         spin_unlock(&st_use_lock);
1269         scsi_tape_put(STp); <-- STp->device = 0 after this
1270         if (resumed)
1271                 scsi_autopm_put_device(STp->device);
1272         return retval;

The ref count for the struct scsi_tape had already been reduced
to 1 when the .remove method of the st module had been called.
The kref_put() in scsi_tape_put() caused scsi_tape_release()
to be called:

0266 static void scsi_tape_put(struct scsi_tape *STp)
0267 {
0268         struct scsi_device *sdev = STp->device;
0269
0270         mutex_lock(&st_ref_mutex);
0271         kref_put(&STp->kref, scsi_tape_release); <-- calls this
0272         scsi_device_put(sdev);
0273         mutex_unlock(&st_ref_mutex);
0274 }

In scsi_tape_release() the struct scsi_device in the struct
scsi_tape gets set to NULL:

4273 static void scsi_tape_release(struct kref *kref)
4274 {
4275         struct scsi_tape *tpnt = to_scsi_tape(kref);
4276         struct gendisk *disk = tpnt->disk;
4277
4278         tpnt->device = NULL; <<<---- where the dev is nulled
4279
4280         if (tpnt->buffer) {
4281                 normalize_buffer(tpnt->buffer);
4282                 kfree(tpnt->buffer->reserved_pages);
4283                 kfree(tpnt->buffer);
4284         }
4285
4286         disk->private_data = NULL;
4287         put_disk(disk);
4288         kfree(tpnt);
4289         return;
4290 }

Although the problem was reported on SLES11.3 the problem appears
in linux-next as well.

The crash is fixed by reordering the code so we no longer access
the struct scsi_tape after the kref_put() is done on it in st_open().

Signed-off-by: Shane Seymour <shane.seymour@hp.com>
Signed-off-by: Darren Lavender <darren.lavender@hp.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.com>
Acked-by: Kai Mäkisara <kai.makisara@kolumbus.fi>
Signed-off-by: James Bottomley <JBottomley@Odin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-10 12:20:30 -07:00
..
accessibility
acpi ACPICA: Tables: Fix an issue that FACS initialization is performed twice 2015-08-03 09:29:46 -07:00
amba
ata libata: force disable trim for SuperSSpeed S238 2015-08-03 09:29:45 -07:00
atm
auxdisplay
base Fix firmware loader uevent buffer NULL pointer dereference 2015-08-03 09:29:47 -07:00
bcma
block rbd: use GFP_NOIO in rbd_obj_request_create() 2015-08-03 09:29:47 -07:00
bluetooth Bluetooth: btusb: Fix memory leak in Intel setup routine 2015-08-03 09:29:42 -07:00
bus bus: mvebu: pass the coherency availability information at init time 2015-07-03 19:48:09 -07:00
cdrom
char agp/intel: Fix typo in needs_ilk_vtd_wa() 2015-08-03 09:29:47 -07:00
clk clk: sunxi: Support factor clocks with N factor starting not from 0 2015-03-18 13:22:34 +01:00
clocksource clocksource: exynos_mct: Fix bitmask regression for exynos4_mct_write 2015-01-29 17:40:56 -08:00
connector net: Use netlink_ns_capable to verify the permisions of netlink messages 2014-06-26 15:12:37 -04:00
cpufreq cpufreq: speedstep-smi: enable interrupts when waiting 2015-03-06 14:40:48 -08:00
cpuidle cpuidle / menu: Return (-1) if there are no suitable states 2015-08-03 09:29:41 -07:00
crypto Revert "crypto: talitos - convert to use be16_add_cpu()" 2015-07-10 10:40:21 -07:00
dca
devfreq
dio
dma dmaengine: mv_xor: bug fix for racing condition in descriptors cleanup 2015-08-03 09:29:46 -07:00
edac sb_edac: Fix erroneous bytes->gigabytes conversion 2015-07-03 19:48:08 -07:00
eisa Revert "EISA: Initialize device before its resources" 2014-02-13 13:47:59 -08:00
extcon extcon: max77693: Fix two NULL pointer exceptions on missing pdata 2014-07-06 18:54:15 -07:00
firewire firewire: cdev: prevent kernel stack leaking into ioctl arguments 2014-11-21 09:22:53 -08:00
firmware efi-pstore: Make efi-pstore return a unique id 2015-02-05 22:35:40 -08:00
gpio gpio: sysfs: fix memory leaks and device hotplug 2015-05-17 09:51:32 -07:00
gpu drm: add a check for x/y in drm_mode_setcrtc 2015-08-03 09:29:45 -07:00
hid HID: fixup the conflicting keyboard mappings quirk 2015-03-18 13:22:35 +01:00
hsi
hv Drivers: hv: vmbus: Don't wait after requesting offers 2015-05-13 05:15:43 -07:00
hwmon hwmon: (mcp3021) Fix broken output scaling 2015-08-03 09:29:46 -07:00
hwspinlock
i2c i2c: at91: fix a race condition when using the DMA controller 2015-08-03 09:29:43 -07:00
ide
idle
iio iio: DAC: ad5624r_spi: fix bit shift of output data value 2015-08-03 09:29:43 -07:00
infiniband iser-target: release stale iser connections 2015-08-03 09:29:46 -07:00
input Input: elantech - fix detection of touchpads where the revision matches a known rate 2015-06-22 16:55:52 -07:00
iommu iommu/vt-d: Fix an off-by-one bug in __domain_mapping() 2015-01-16 06:59:01 -08:00
ipack
irqchip irqchip: gic: Fix core ID calculation when topology is read from DT 2014-07-28 08:00:06 -07:00
isdn isdnloop: several buffer overflows 2014-04-14 06:42:18 -07:00
leds leds: leds-pwm: properly clean up after probe failure 2014-06-07 13:25:34 -07:00
lguest lguest: fix out-by-one error in address checking. 2015-06-05 23:19:54 -07:00
macintosh
mailbox
md md: fix a build warning 2015-08-03 09:29:46 -07:00
media cx24116: fix a buffer overflow when checking userspace params 2015-08-03 09:29:44 -07:00
memory
memstick memstick: mspro_block: add missing curly braces 2015-05-06 21:56:28 +02:00
message mptfusion: enable no_write_same for vmware scsi disks 2014-10-30 09:35:10 -07:00
mfd mfd: tc6393xb: Fail ohci suspend if full state restore is required 2015-01-08 09:58:15 -08:00
misc mei: bus: fix possible boundaries violation 2014-11-21 09:22:55 -08:00
mmc mmc: card: Fixup request missing in mmc_blk_issue_rw_rq 2015-08-03 09:29:46 -07:00
mtd mtd: dc21285: use raw spinlock functions for nw_gpio_lock 2015-08-03 09:29:41 -07:00
net ath9k: fix DMA stop sequence for AR9003+ 2015-08-03 09:29:42 -07:00
nfc NFC: microread: Potential overflows in microread_target_discovered() 2014-10-05 14:54:12 -07:00
ntb
nubus
of of/base: Fix PowerPC address parsing hack 2014-12-06 15:05:47 -08:00
oprofile
parisc
parport drivers: parport: Kconfig: exclude arm64 for PARPORT_PC 2015-05-06 21:56:26 +02:00
pci PCI: Fix infinite loop with ROM image of size 0 2015-03-06 14:40:48 -08:00
pcmcia Disable write buffering on Toshiba ToPIC95 2015-08-03 09:29:41 -07:00
pinctrl pinctrl: mvebu: armada-xp: fix functions of MPP48 2015-08-03 09:29:42 -07:00
platform hp_accel: Add support for HP ZBook 15 2015-01-27 07:52:31 -08:00
pnp PNP / ACPI: proper handling of ACPI IO/Memory resource parsing failures 2014-03-23 21:38:22 -07:00
power power_supply: lp8788-charger: Fix leaked power supply on probe fail 2015-05-06 21:56:21 +02:00
pps
ps3
ptp
pwm
rapidio rapidio/tsi721_dma: fix failure to obtain transaction descriptor 2014-08-07 14:30:25 -07:00
regulator regulator: core: fix constraints output buffer 2015-08-03 09:29:41 -07:00
remoteproc
reset
rpmsg
rtc rtc: rtc-at91rm9200: fix infinite wait for ACKUPD irq 2014-06-26 15:12:37 -04:00
s390 crypto: prefix module autoloading with "crypto-" 2015-01-29 17:40:57 -08:00
sbus bbc-i2c: Fix BBC I2C envctrl on SunBlade 2000 2014-08-14 09:24:16 +08:00
scsi st: null pointer dereference panic caused by use after kref_put by st_open 2015-08-10 12:20:30 -07:00
sfi
sh
sn
spi spi: spidev: fix possible arithmetic overflow for multi-transfer message 2015-05-06 21:56:21 +02:00
ssb
ssbi
staging staging: rtl8712: prevent buffer overrun in recvbuf2recvframe 2015-08-03 09:29:42 -07:00
target iscsi-target: Convert iscsi_thread_set usage to kthread.h 2015-08-03 09:29:46 -07:00
tc
thermal
tty xen/console: Update console event channel on resume 2015-05-17 09:51:32 -07:00
uio
usb USB: usbfs: allow URBs to be reaped after disconnection 2015-08-03 09:29:47 -07:00
uwb
vfio vfio-pci: Fix the check on pci device type in vfio_pci_probe() 2015-01-27 07:52:32 -08:00
vhost vhost-scsi: Add missing virtio-scsi -> TCM attribute conversion 2015-02-05 22:35:40 -08:00
video video: vgacon: Don't build on arm64 2015-05-06 21:56:25 +02:00
virt
virtio virtio_pci: fix virtio spec compliance on restore 2014-11-14 08:47:55 -08:00
vlynq
vme VME: Correct read/write alignment algorithm 2014-02-22 12:41:28 -08:00
w1 w1: fix w1_send_slave dropping a slave id 2014-05-06 07:55:28 -07:00
watchdog watchdog: omap: assert the counter being stopped before reprogramming 2015-08-03 09:29:47 -07:00
xen xen-pciback: limit guest control of command register 2015-03-26 15:00:59 +01:00
zorro
Kconfig
Makefile