linux-stable.git/drivers/mtd, branch v3.2.83 Linux kernel stable tree ubi: Make recover_peb power cut aware 2016-08-22T21:37:15+00:00 Richard Weinberger richard@nod.at 2016-06-20T22:31:50+00:00 bedbc047e74d0962e194eb0018e9e1dbd7b9402f commit 972228d87445dc46c0a01f5f3de673ac017626f7 upstream. recover_peb() was never power cut aware, if a power cut happened right after writing the VID header upon next attach UBI would blindly use the new partial written PEB and all data from the old PEB is lost. In order to make recover_peb() power cut aware, write the new VID with a proper crc and copy_flag set such that the UBI attach process will detect whether the new PEB is completely written or not. We cannot directly use ubi_eba_atomic_leb_change() since we'd have to unlock the LEB which is facing a write error. Reported-by: Jörg Pfähler <pfaehler@isse.de> Reviewed-by: Jörg Pfähler <pfaehler@isse.de> Signed-off-by: Richard Weinberger <richard@nod.at> [bwh: Backported to 3.2: - Adjust context - Use next_sqnum() instead of ubi_next_sqnum() - Use ubi_device::peb_buf1 instead of ubi_device::peb_buf - No need to unlock ubi->fm_eba_sem on error] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 972228d87445dc46c0a01f5f3de673ac017626f7 upstream.

recover_peb() was never power cut aware,
if a power cut happened right after writing the VID header
upon next attach UBI would blindly use the new partial written
PEB and all data from the old PEB is lost.

In order to make recover_peb() power cut aware, write the new
VID with a proper crc and copy_flag set such that the UBI attach
process will detect whether the new PEB is completely written
or not.
We cannot directly use ubi_eba_atomic_leb_change() since we'd
have to unlock the LEB which is facing a write error.

Reported-by: Jörg Pfähler <pfaehler@isse.de>
Reviewed-by: Jörg Pfähler <pfaehler@isse.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
[bwh: Backported to 3.2:
 - Adjust context
 - Use next_sqnum() instead of ubi_next_sqnum()
 - Use ubi_device::peb_buf1 instead of ubi_device::peb_buf
 - No need to unlock ubi->fm_eba_sem on error]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ubi: Fix out of bounds write in volume update code 2016-04-01T00:54:37+00:00 Richard Weinberger richard@nod.at 2016-02-21T09:53:03+00:00 7aae79649d6a88e7104d4d22aa4ba21f4e699e40 commit e4f6daac20332448529b11f09388f1d55ef2084c upstream. ubi_start_leb_change() allocates too few bytes. ubi_more_leb_change_data() will write up to req->upd_bytes + ubi->min_io_size bytes. Signed-off-by: Richard Weinberger <richard@nod.at> Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e4f6daac20332448529b11f09388f1d55ef2084c upstream.

ubi_start_leb_change() allocates too few bytes.
ubi_more_leb_change_data() will write up to req->upd_bytes +
ubi->min_io_size bytes.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
mtd: blkdevs: fix potential deadlock + lockdep warnings 2015-11-27T12:48:22+00:00 Brian Norris computersforpeace@gmail.com 2015-10-26T17:20:23+00:00 419608b9adde80d8638daa01c8614e1b92416fc0 commit f3c63795e90f0c6238306883b6c72f14d5355721 upstream. Commit 073db4a51ee4 ("mtd: fix: avoid race condition when accessing mtd->usecount") fixed a race condition but due to poor ordering of the mutex acquisition, introduced a potential deadlock. The deadlock can occur, for example, when rmmod'ing the m25p80 module, which will delete one or more MTDs, along with any corresponding mtdblock devices. This could potentially race with an acquisition of the block device as follows. -> blktrans_open() -> mutex_lock(&dev->lock); -> mutex_lock(&mtd_table_mutex); -> del_mtd_device() -> mutex_lock(&mtd_table_mutex); -> blktrans_notify_remove() -> del_mtd_blktrans_dev() -> mutex_lock(&dev->lock); This is a classic (potential) ABBA deadlock, which can be fixed by making the A->B ordering consistent everywhere. There was no real purpose to the ordering in the original patch, AFAIR, so this shouldn't be a problem. This ordering was actually already present in del_mtd_blktrans_dev(), for one, where the function tried to ensure that its caller already held mtd_table_mutex before it acquired &dev->lock: if (mutex_trylock(&mtd_table_mutex)) { mutex_unlock(&mtd_table_mutex); BUG(); } So, reverse the ordering of acquisition of &dev->lock and &mtd_table_mutex so we always acquire mtd_table_mutex first. Snippets of the lockdep output follow: # modprobe -r m25p80 [ 53.419251] [ 53.420838] ====================================================== [ 53.427300] [ INFO: possible circular locking dependency detected ] [ 53.433865] 4.3.0-rc6 #96 Not tainted [ 53.437686] ------------------------------------------------------- [ 53.444220] modprobe/372 is trying to acquire lock: [ 53.449320] (&new->lock){+.+...}, at: [<c043fe4c>] del_mtd_blktrans_dev+0x80/0xdc [ 53.457271] [ 53.457271] but task is already holding lock: [ 53.463372] (mtd_table_mutex){+.+.+.}, at: [<c0439994>] del_mtd_device+0x18/0x100 [ 53.471321] [ 53.471321] which lock already depends on the new lock. [ 53.471321] [ 53.479856] [ 53.479856] the existing dependency chain (in reverse order) is: [ 53.487660] -> #1 (mtd_table_mutex){+.+.+.}: [ 53.492331] [<c043fc5c>] blktrans_open+0x34/0x1a4 [ 53.497879] [<c01afce0>] __blkdev_get+0xc4/0x3b0 [ 53.503364] [<c01b0bb8>] blkdev_get+0x108/0x320 [ 53.508743] [<c01713c0>] do_dentry_open+0x218/0x314 [ 53.514496] [<c0180454>] path_openat+0x4c0/0xf9c [ 53.519959] [<c0182044>] do_filp_open+0x5c/0xc0 [ 53.525336] [<c0172758>] do_sys_open+0xfc/0x1cc [ 53.530716] [<c000f740>] ret_fast_syscall+0x0/0x1c [ 53.536375] -> #0 (&new->lock){+.+...}: [ 53.540587] [<c063f124>] mutex_lock_nested+0x38/0x3cc [ 53.546504] [<c043fe4c>] del_mtd_blktrans_dev+0x80/0xdc [ 53.552606] [<c043f164>] blktrans_notify_remove+0x7c/0x84 [ 53.558891] [<c04399f0>] del_mtd_device+0x74/0x100 [ 53.564544] [<c043c670>] del_mtd_partitions+0x80/0xc8 [ 53.570451] [<c0439aa0>] mtd_device_unregister+0x24/0x48 [ 53.576637] [<c046ce6c>] spi_drv_remove+0x1c/0x34 [ 53.582207] [<c03de0f0>] __device_release_driver+0x88/0x114 [ 53.588663] [<c03de19c>] device_release_driver+0x20/0x2c [ 53.594843] [<c03dd9e8>] bus_remove_device+0xd8/0x108 [ 53.600748] [<c03dacc0>] device_del+0x10c/0x210 [ 53.606127] [<c03dadd0>] device_unregister+0xc/0x20 [ 53.611849] [<c046d878>] __unregister+0x10/0x20 [ 53.617211] [<c03da868>] device_for_each_child+0x50/0x7c [ 53.623387] [<c046eae8>] spi_unregister_master+0x58/0x8c [ 53.629578] [<c03e12f0>] release_nodes+0x15c/0x1c8 [ 53.635223] [<c03de0f8>] __device_release_driver+0x90/0x114 [ 53.641689] [<c03de900>] driver_detach+0xb4/0xb8 [ 53.647147] [<c03ddc78>] bus_remove_driver+0x4c/0xa0 [ 53.652970] [<c00cab50>] SyS_delete_module+0x11c/0x1e4 [ 53.658976] [<c000f740>] ret_fast_syscall+0x0/0x1c [ 53.664621] [ 53.664621] other info that might help us debug this: [ 53.664621] [ 53.672979] Possible unsafe locking scenario: [ 53.672979] [ 53.679169] CPU0 CPU1 [ 53.683900] ---- ---- [ 53.688633] lock(mtd_table_mutex); [ 53.692383] lock(&new->lock); [ 53.698306] lock(mtd_table_mutex); [ 53.704658] lock(&new->lock); [ 53.707946] [ 53.707946] *** DEADLOCK *** Fixes: 073db4a51ee4 ("mtd: fix: avoid race condition when accessing mtd->usecount") Reported-by: Felipe Balbi <balbi@ti.com> Tested-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit f3c63795e90f0c6238306883b6c72f14d5355721 upstream.

Commit 073db4a51ee4 ("mtd: fix: avoid race condition when accessing
mtd->usecount") fixed a race condition but due to poor ordering of the
mutex acquisition, introduced a potential deadlock.

The deadlock can occur, for example, when rmmod'ing the m25p80 module, which
will delete one or more MTDs, along with any corresponding mtdblock
devices. This could potentially race with an acquisition of the block
device as follows.

 -> blktrans_open()
    ->  mutex_lock(&dev->lock);
    ->  mutex_lock(&mtd_table_mutex);

 -> del_mtd_device()
    ->  mutex_lock(&mtd_table_mutex);
    ->  blktrans_notify_remove() -> del_mtd_blktrans_dev()
       ->  mutex_lock(&dev->lock);

This is a classic (potential) ABBA deadlock, which can be fixed by
making the A->B ordering consistent everywhere. There was no real
purpose to the ordering in the original patch, AFAIR, so this shouldn't
be a problem. This ordering was actually already present in
del_mtd_blktrans_dev(), for one, where the function tried to ensure that
its caller already held mtd_table_mutex before it acquired &dev->lock:

        if (mutex_trylock(&mtd_table_mutex)) {
                mutex_unlock(&mtd_table_mutex);
                BUG();
        }

So, reverse the ordering of acquisition of &dev->lock and &mtd_table_mutex so
we always acquire mtd_table_mutex first.

Snippets of the lockdep output follow:

  # modprobe -r m25p80
  [   53.419251]
  [   53.420838] ======================================================
  [   53.427300] [ INFO: possible circular locking dependency detected ]
  [   53.433865] 4.3.0-rc6 #96 Not tainted
  [   53.437686] -------------------------------------------------------
  [   53.444220] modprobe/372 is trying to acquire lock:
  [   53.449320]  (&new->lock){+.+...}, at: [<c043fe4c>] del_mtd_blktrans_dev+0x80/0xdc
  [   53.457271]
  [   53.457271] but task is already holding lock:
  [   53.463372]  (mtd_table_mutex){+.+.+.}, at: [<c0439994>] del_mtd_device+0x18/0x100
  [   53.471321]
  [   53.471321] which lock already depends on the new lock.
  [   53.471321]
  [   53.479856]
  [   53.479856] the existing dependency chain (in reverse order) is:
  [   53.487660]
  -> #1 (mtd_table_mutex){+.+.+.}:
  [   53.492331]        [<c043fc5c>] blktrans_open+0x34/0x1a4
  [   53.497879]        [<c01afce0>] __blkdev_get+0xc4/0x3b0
  [   53.503364]        [<c01b0bb8>] blkdev_get+0x108/0x320
  [   53.508743]        [<c01713c0>] do_dentry_open+0x218/0x314
  [   53.514496]        [<c0180454>] path_openat+0x4c0/0xf9c
  [   53.519959]        [<c0182044>] do_filp_open+0x5c/0xc0
  [   53.525336]        [<c0172758>] do_sys_open+0xfc/0x1cc
  [   53.530716]        [<c000f740>] ret_fast_syscall+0x0/0x1c
  [   53.536375]
  -> #0 (&new->lock){+.+...}:
  [   53.540587]        [<c063f124>] mutex_lock_nested+0x38/0x3cc
  [   53.546504]        [<c043fe4c>] del_mtd_blktrans_dev+0x80/0xdc
  [   53.552606]        [<c043f164>] blktrans_notify_remove+0x7c/0x84
  [   53.558891]        [<c04399f0>] del_mtd_device+0x74/0x100
  [   53.564544]        [<c043c670>] del_mtd_partitions+0x80/0xc8
  [   53.570451]        [<c0439aa0>] mtd_device_unregister+0x24/0x48
  [   53.576637]        [<c046ce6c>] spi_drv_remove+0x1c/0x34
  [   53.582207]        [<c03de0f0>] __device_release_driver+0x88/0x114
  [   53.588663]        [<c03de19c>] device_release_driver+0x20/0x2c
  [   53.594843]        [<c03dd9e8>] bus_remove_device+0xd8/0x108
  [   53.600748]        [<c03dacc0>] device_del+0x10c/0x210
  [   53.606127]        [<c03dadd0>] device_unregister+0xc/0x20
  [   53.611849]        [<c046d878>] __unregister+0x10/0x20
  [   53.617211]        [<c03da868>] device_for_each_child+0x50/0x7c
  [   53.623387]        [<c046eae8>] spi_unregister_master+0x58/0x8c
  [   53.629578]        [<c03e12f0>] release_nodes+0x15c/0x1c8
  [   53.635223]        [<c03de0f8>] __device_release_driver+0x90/0x114
  [   53.641689]        [<c03de900>] driver_detach+0xb4/0xb8
  [   53.647147]        [<c03ddc78>] bus_remove_driver+0x4c/0xa0
  [   53.652970]        [<c00cab50>] SyS_delete_module+0x11c/0x1e4
  [   53.658976]        [<c000f740>] ret_fast_syscall+0x0/0x1c
  [   53.664621]
  [   53.664621] other info that might help us debug this:
  [   53.664621]
  [   53.672979]  Possible unsafe locking scenario:
  [   53.672979]
  [   53.679169]        CPU0                    CPU1
  [   53.683900]        ----                    ----
  [   53.688633]   lock(mtd_table_mutex);
  [   53.692383]                                lock(&new->lock);
  [   53.698306]                                lock(mtd_table_mutex);
  [   53.704658]   lock(&new->lock);
  [   53.707946]
  [   53.707946]  *** DEADLOCK ***

Fixes: 073db4a51ee4 ("mtd: fix: avoid race condition when accessing mtd->usecount")
Reported-by: Felipe Balbi <balbi@ti.com>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
mtd: mtdpart: fix add_mtd_partitions error path 2015-11-27T12:48:19+00:00 Boris BREZILLON boris.brezillon@free-electrons.com 2015-07-30T10:18:03+00:00 f9ac3882c96ad4d554be337d28ea202988b68b3d commit e5bae86797141e4a95e42d825f737cb36d7b8c37 upstream. If we fail to allocate a partition structure in the middle of the partition creation process, the already allocated partitions are never removed, which means they are still present in the partition list and their resources are never freed. Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e5bae86797141e4a95e42d825f737cb36d7b8c37 upstream.

If we fail to allocate a partition structure in the middle of the partition
creation process, the already allocated partitions are never removed, which
means they are still present in the partition list and their resources are
never freed.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
UBI: return ENOSPC if no enough space available 2015-11-17T15:54:41+00:00 shengyong shengyong1@huawei.com 2015-09-28T17:57:19+00:00 02eb3b901e81417a8a0c9f2338fa24d8a7d00093 commit 7c7feb2ebfc9c0552c51f0c050db1d1a004faac5 upstream. UBI: attaching mtd1 to ubi0 UBI: scanning is finished UBI error: init_volumes: not enough PEBs, required 706, available 686 UBI error: ubi_wl_init: no enough physical eraseblocks (-20, need 1) UBI error: ubi_attach_mtd_dev: failed to attach mtd1, error -12 <= NOT ENOMEM UBI error: ubi_init: cannot attach mtd1 If available PEBs are not enough when initializing volumes, return -ENOSPC directly. If available PEBs are not enough when initializing WL, return -ENOSPC instead of -ENOMEM. Signed-off-by: Sheng Yong <shengyong1@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> Reviewed-by: David Gstir <david@sigma-star.at> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 7c7feb2ebfc9c0552c51f0c050db1d1a004faac5 upstream.

UBI: attaching mtd1 to ubi0
UBI: scanning is finished
UBI error: init_volumes: not enough PEBs, required 706, available 686
UBI error: ubi_wl_init: no enough physical eraseblocks (-20, need 1)
UBI error: ubi_attach_mtd_dev: failed to attach mtd1, error -12 <= NOT ENOMEM
UBI error: ubi_init: cannot attach mtd1

If available PEBs are not enough when initializing volumes, return -ENOSPC
directly. If available PEBs are not enough when initializing WL, return
-ENOSPC instead of -ENOMEM.

Signed-off-by: Sheng Yong <shengyong1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: David Gstir <david@sigma-star.at>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
UBI: Validate data_size 2015-11-17T15:54:41+00:00 Richard Weinberger richard@nod.at 2015-09-22T21:58:07+00:00 73d95e7b04162376761b6c942d74cd18b1556dce commit 281fda27673f833a01d516658a64d22a32c8e072 upstream. Make sure that data_size is less than LEB size. Otherwise a handcrafted UBI image is able to trigger an out of bounds memory access in ubi_compare_lebs(). Signed-off-by: Richard Weinberger <richard@nod.at> Reviewed-by: David Gstir <david@sigma-star.at> [bwh: Backported to 3.2: drop first argument to ubi_err()] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 281fda27673f833a01d516658a64d22a32c8e072 upstream.

Make sure that data_size is less than LEB size.
Otherwise a handcrafted UBI image is able to trigger
an out of bounds memory access in ubi_compare_lebs().

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: David Gstir <david@sigma-star.at>
[bwh: Backported to 3.2: drop first argument to ubi_err()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
mtd: dc21285: use raw spinlock functions for nw_gpio_lock 2015-08-12T14:33:13+00:00 Uwe Kleine-König u.kleine-koenig@pengutronix.de 2015-05-28T08:22:10+00:00 3d0b261c65b60df9dde561616217f93f8e411bdb commit e5babdf928e5d0c432a8d4b99f20421ce14d1ab6 upstream. Since commit bd31b85960a7 (which is in 3.2-rc1) nw_gpio_lock is a raw spinlock that needs usage of the corresponding raw functions. This fixes: drivers/mtd/maps/dc21285.c: In function 'nw_en_write': drivers/mtd/maps/dc21285.c:41:340: warning: passing argument 1 of 'spinlock_check' from incompatible pointer type spin_lock_irqsave(&nw_gpio_lock, flags); In file included from include/linux/seqlock.h:35:0, from include/linux/time.h:5, from include/linux/stat.h:18, from include/linux/module.h:10, from drivers/mtd/maps/dc21285.c:8: include/linux/spinlock.h:299:102: note: expected 'struct spinlock_t *' but argument is of type 'struct raw_spinlock_t *' static inline raw_spinlock_t *spinlock_check(spinlock_t *lock) ^ drivers/mtd/maps/dc21285.c:43:25: warning: passing argument 1 of 'spin_unlock_irqrestore' from incompatible pointer type spin_unlock_irqrestore(&nw_gpio_lock, flags); ^ In file included from include/linux/seqlock.h:35:0, from include/linux/time.h:5, from include/linux/stat.h:18, from include/linux/module.h:10, from drivers/mtd/maps/dc21285.c:8: include/linux/spinlock.h:370:91: note: expected 'struct spinlock_t *' but argument is of type 'struct raw_spinlock_t *' static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags) Fixes: bd31b85960a7 ("locking, ARM: Annotate low level hw locks as raw") Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit e5babdf928e5d0c432a8d4b99f20421ce14d1ab6 upstream.

Since commit bd31b85960a7 (which is in 3.2-rc1) nw_gpio_lock is a raw spinlock
that needs usage of the corresponding raw functions.

This fixes:

  drivers/mtd/maps/dc21285.c: In function 'nw_en_write':
  drivers/mtd/maps/dc21285.c:41:340: warning: passing argument 1 of 'spinlock_check' from incompatible pointer type
    spin_lock_irqsave(&nw_gpio_lock, flags);

  In file included from include/linux/seqlock.h:35:0,
                   from include/linux/time.h:5,
                   from include/linux/stat.h:18,
                   from include/linux/module.h:10,
                   from drivers/mtd/maps/dc21285.c:8:
  include/linux/spinlock.h:299:102: note: expected 'struct spinlock_t *' but argument is of type 'struct raw_spinlock_t *'
   static inline raw_spinlock_t *spinlock_check(spinlock_t *lock)
                                                                                                        ^
  drivers/mtd/maps/dc21285.c:43:25: warning: passing argument 1 of 'spin_unlock_irqrestore' from incompatible pointer type
    spin_unlock_irqrestore(&nw_gpio_lock, flags);
                           ^
  In file included from include/linux/seqlock.h:35:0,
                   from include/linux/time.h:5,
                   from include/linux/stat.h:18,
                   from include/linux/module.h:10,
                   from drivers/mtd/maps/dc21285.c:8:
  include/linux/spinlock.h:370:91: note: expected 'struct spinlock_t *' but argument is of type 'struct raw_spinlock_t *'
   static inline void spin_unlock_irqrestore(spinlock_t *lock, unsigned long flags)

Fixes: bd31b85960a7 ("locking, ARM: Annotate low level hw locks as raw")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
mtd: fix: avoid race condition when accessing mtd->usecount 2015-08-12T14:33:11+00:00 Brian Norris computersforpeace@gmail.com 2015-05-08T00:55:16+00:00 5d8caffb9c2959cf994a109174981a443c213686 commit 073db4a51ee43ccb827f54a4261c0583b028d5ab upstream. On A MIPS 32-cores machine a BUG_ON was triggered because some acesses to mtd->usecount were done without taking mtd_table_mutex. kernel: Call Trace: kernel: [<ffffffff80401818>] __put_mtd_device+0x20/0x50 kernel: [<ffffffff804086f4>] blktrans_release+0x8c/0xd8 kernel: [<ffffffff802577e0>] __blkdev_put+0x1a8/0x200 kernel: [<ffffffff802579a4>] blkdev_close+0x1c/0x30 kernel: [<ffffffff8022006c>] __fput+0xac/0x250 kernel: [<ffffffff80171208>] task_work_run+0xd8/0x120 kernel: [<ffffffff8012c23c>] work_notifysig+0x10/0x18 kernel: kernel: Code: 2442ffff ac8202d8 000217fe <00020336> dc820128 10400003 00000000 0040f809 00000000 kernel: ---[ end trace 080fbb4579b47a73 ]--- Fixed by taking the mutex in blktrans_open and blktrans_release. Note that this locking is already suggested in include/linux/mtd/blktrans.h: struct mtd_blktrans_ops { ... /* Called with mtd_table_mutex held; no race with add/remove */ int (*open)(struct mtd_blktrans_dev *dev); void (*release)(struct mtd_blktrans_dev *dev); ... }; But we weren't following it. Originally reported by (and patched by) Zhang and Giuseppe, independently. Improved and rewritten. Reported-by: Zhang Xingcai <zhangxingcai@huawei.com> Reported-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com> Tested-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com> Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Signed-off-by: Brian Norris <computersforpeace@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 073db4a51ee43ccb827f54a4261c0583b028d5ab upstream.

On A MIPS 32-cores machine a BUG_ON was triggered because some acesses to
mtd->usecount were done without taking mtd_table_mutex.
kernel: Call Trace:
kernel: [<ffffffff80401818>] __put_mtd_device+0x20/0x50
kernel: [<ffffffff804086f4>] blktrans_release+0x8c/0xd8
kernel: [<ffffffff802577e0>] __blkdev_put+0x1a8/0x200
kernel: [<ffffffff802579a4>] blkdev_close+0x1c/0x30
kernel: [<ffffffff8022006c>] __fput+0xac/0x250
kernel: [<ffffffff80171208>] task_work_run+0xd8/0x120
kernel: [<ffffffff8012c23c>] work_notifysig+0x10/0x18
kernel:
kernel:
        Code: 2442ffff  ac8202d8  000217fe <00020336> dc820128  10400003
               00000000  0040f809  00000000
kernel: ---[ end trace 080fbb4579b47a73 ]---

Fixed by taking the mutex in blktrans_open and blktrans_release.

Note that this locking is already suggested in
include/linux/mtd/blktrans.h:

struct mtd_blktrans_ops {
...
	/* Called with mtd_table_mutex held; no race with add/remove */
	int (*open)(struct mtd_blktrans_dev *dev);
	void (*release)(struct mtd_blktrans_dev *dev);
...
};

But we weren't following it.

Originally reported by (and patched by) Zhang and Giuseppe,
independently. Improved and rewritten.

Reported-by: Zhang Xingcai <zhangxingcai@huawei.com>
Reported-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Tested-by: Giuseppe Cantavenera <giuseppe.cantavenera.ext@nokia.com>
Acked-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
UBI: fix soft lockup in ubi_check_volume() 2015-08-06T23:32:19+00:00 hujianyang hujianyang@huawei.com 2014-12-30T03:56:09+00:00 6876b78ee008e416e3802e376cf9392e14b9c92a commit 9aa272b492e7551a9ee0e2c83c720ea013698485 upstream. Running mtd-utils/tests/ubi-tests/io_basic.c could cause soft lockup or watchdog reset. It is because *updatevol* will perform ubi_check_volume() after updating finish and this function will full scan the updated lebs if the volume is initialized as STATIC_VOLUME. This patch adds *cond_resched()* in the loop of lebs scan to avoid soft lockup. Helped by Richard Weinberger <richard@nod.at> [ 2158.067096] INFO: rcu_sched self-detected stall on CPU { 1} (t=2101 jiffies g=1606 c=1605 q=56) [ 2158.172867] CPU: 1 PID: 2073 Comm: io_basic Tainted: G O 3.10.53 #21 [ 2158.172898] [<c000f624>] (unwind_backtrace+0x0/0x120) from [<c000c294>] (show_stack+0x10/0x14) [ 2158.172918] [<c000c294>] (show_stack+0x10/0x14) from [<c008ac3c>] (rcu_check_callbacks+0x1c0/0x660) [ 2158.172936] [<c008ac3c>] (rcu_check_callbacks+0x1c0/0x660) from [<c002b480>] (update_process_times+0x38/0x64) [ 2158.172953] [<c002b480>] (update_process_times+0x38/0x64) from [<c005ff38>] (tick_sched_handle+0x54/0x60) [ 2158.172966] [<c005ff38>] (tick_sched_handle+0x54/0x60) from [<c00601ac>] (tick_sched_timer+0x44/0x74) [ 2158.172978] [<c00601ac>] (tick_sched_timer+0x44/0x74) from [<c003f348>] (__run_hrtimer+0xc8/0x1b8) [ 2158.172992] [<c003f348>] (__run_hrtimer+0xc8/0x1b8) from [<c003fd9c>] (hrtimer_interrupt+0x128/0x2a4) [ 2158.173007] [<c003fd9c>] (hrtimer_interrupt+0x128/0x2a4) from [<c0246f1c>] (arch_timer_handler_virt+0x28/0x30) [ 2158.173022] [<c0246f1c>] (arch_timer_handler_virt+0x28/0x30) from [<c0086214>] (handle_percpu_devid_irq+0x9c/0x124) [ 2158.173036] [<c0086214>] (handle_percpu_devid_irq+0x9c/0x124) from [<c0082bd8>] (generic_handle_irq+0x20/0x30) [ 2158.173049] [<c0082bd8>] (generic_handle_irq+0x20/0x30) from [<c000969c>] (handle_IRQ+0x64/0x8c) [ 2158.173060] [<c000969c>] (handle_IRQ+0x64/0x8c) from [<c0008544>] (gic_handle_irq+0x3c/0x60) [ 2158.173074] [<c0008544>] (gic_handle_irq+0x3c/0x60) from [<c02f0f80>] (__irq_svc+0x40/0x50) [ 2158.173083] Exception stack(0xc4043c98 to 0xc4043ce0) [ 2158.173092] 3c80: c4043ce4 00000019 [ 2158.173102] 3ca0: 1f8a865f c050ad10 1f8a864c 00000031 c04b5970 0003ebce 00000000 f3550000 [ 2158.173113] 3cc0: bf00bc68 00000800 0003ebce c4043ce0 c0186d14 c0186cb8 80000013 ffffffff [ 2158.173130] [<c02f0f80>] (__irq_svc+0x40/0x50) from [<c0186cb8>] (read_current_timer+0x4/0x38) [ 2158.173145] [<c0186cb8>] (read_current_timer+0x4/0x38) from [<1f8a865f>] (0x1f8a865f) [ 2183.927097] BUG: soft lockup - CPU#1 stuck for 22s! [io_basic:2073] [ 2184.002229] Modules linked in: nandflash(O) [last unloaded: nandflash] Signed-off-by: Wang Kai <morgan.wang@huawei.com> Signed-off-by: hujianyang <hujianyang@huawei.com> Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 9aa272b492e7551a9ee0e2c83c720ea013698485 upstream.

Running mtd-utils/tests/ubi-tests/io_basic.c could cause
soft lockup or watchdog reset. It is because *updatevol*
will perform ubi_check_volume() after updating finish
and this function will full scan the updated lebs if the
volume is initialized as STATIC_VOLUME.

This patch adds *cond_resched()* in the loop of lebs scan
to avoid soft lockup.

Helped by Richard Weinberger <richard@nod.at>

[ 2158.067096] INFO: rcu_sched self-detected stall on CPU { 1}  (t=2101 jiffies g=1606 c=1605 q=56)
[ 2158.172867] CPU: 1 PID: 2073 Comm: io_basic Tainted: G           O 3.10.53 #21
[ 2158.172898] [<c000f624>] (unwind_backtrace+0x0/0x120) from [<c000c294>] (show_stack+0x10/0x14)
[ 2158.172918] [<c000c294>] (show_stack+0x10/0x14) from [<c008ac3c>] (rcu_check_callbacks+0x1c0/0x660)
[ 2158.172936] [<c008ac3c>] (rcu_check_callbacks+0x1c0/0x660) from [<c002b480>] (update_process_times+0x38/0x64)
[ 2158.172953] [<c002b480>] (update_process_times+0x38/0x64) from [<c005ff38>] (tick_sched_handle+0x54/0x60)
[ 2158.172966] [<c005ff38>] (tick_sched_handle+0x54/0x60) from [<c00601ac>] (tick_sched_timer+0x44/0x74)
[ 2158.172978] [<c00601ac>] (tick_sched_timer+0x44/0x74) from [<c003f348>] (__run_hrtimer+0xc8/0x1b8)
[ 2158.172992] [<c003f348>] (__run_hrtimer+0xc8/0x1b8) from [<c003fd9c>] (hrtimer_interrupt+0x128/0x2a4)
[ 2158.173007] [<c003fd9c>] (hrtimer_interrupt+0x128/0x2a4) from [<c0246f1c>] (arch_timer_handler_virt+0x28/0x30)
[ 2158.173022] [<c0246f1c>] (arch_timer_handler_virt+0x28/0x30) from [<c0086214>] (handle_percpu_devid_irq+0x9c/0x124)
[ 2158.173036] [<c0086214>] (handle_percpu_devid_irq+0x9c/0x124) from [<c0082bd8>] (generic_handle_irq+0x20/0x30)
[ 2158.173049] [<c0082bd8>] (generic_handle_irq+0x20/0x30) from [<c000969c>] (handle_IRQ+0x64/0x8c)
[ 2158.173060] [<c000969c>] (handle_IRQ+0x64/0x8c) from [<c0008544>] (gic_handle_irq+0x3c/0x60)
[ 2158.173074] [<c0008544>] (gic_handle_irq+0x3c/0x60) from [<c02f0f80>] (__irq_svc+0x40/0x50)
[ 2158.173083] Exception stack(0xc4043c98 to 0xc4043ce0)
[ 2158.173092] 3c80:                                                       c4043ce4 00000019
[ 2158.173102] 3ca0: 1f8a865f c050ad10 1f8a864c 00000031 c04b5970 0003ebce 00000000 f3550000
[ 2158.173113] 3cc0: bf00bc68 00000800 0003ebce c4043ce0 c0186d14 c0186cb8 80000013 ffffffff
[ 2158.173130] [<c02f0f80>] (__irq_svc+0x40/0x50) from [<c0186cb8>] (read_current_timer+0x4/0x38)
[ 2158.173145] [<c0186cb8>] (read_current_timer+0x4/0x38) from [<1f8a865f>] (0x1f8a865f)
[ 2183.927097] BUG: soft lockup - CPU#1 stuck for 22s! [io_basic:2073]
[ 2184.002229] Modules linked in: nandflash(O) [last unloaded: nandflash]

Signed-off-by: Wang Kai <morgan.wang@huawei.com>
Signed-off-by: hujianyang <hujianyang@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
UBI: fix check for "too many bytes" 2015-08-06T23:32:01+00:00 Brian Norris computersforpeace@gmail.com 2015-02-28T10:23:28+00:00 e406cf29146f6aa1213a573dcc96c661c4a485c5 commit 299d0c5b27346a77a0777c993372bf8777d4f2e5 upstream. The comparison from the previous line seems to have been erroneously (partially) copied-and-pasted onto the next. The second line should be checking req.bytes, not req.lnum. Coverity CID #139400 Signed-off-by: Brian Norris <computersforpeace@gmail.com> [rw: Fixed comparison] Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 299d0c5b27346a77a0777c993372bf8777d4f2e5 upstream.

The comparison from the previous line seems to have been erroneously
(partially) copied-and-pasted onto the next. The second line should be
checking req.bytes, not req.lnum.

Coverity CID #139400

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
[rw: Fixed comparison]
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>