]> git.baikalelectronics.ru Git - kernel.git/commit
gpio: max732x: Fix possible deadlock
authorSemen Protsenko <semen.protsenko@globallogic.com>
Tue, 13 Jan 2015 13:41:44 +0000 (15:41 +0200)
committerLinus Walleij <linus.walleij@linaro.org>
Thu, 15 Jan 2015 17:03:49 +0000 (18:03 +0100)
commit6c084e695c536246138b98bc106ceb9165ecb56c
tree58551a32dd3959887c5e19b7f7b7ea0d8544962a
parent722e01d5ec1992bd6e7022103946e0132735ec18
gpio: max732x: Fix possible deadlock

This patch was derived from next one:
"gpio: fix pca953x set_type 'scheduling while atomic' bug".

After adding entry that consumes max732x GPIO as interrupt line to dts
file, deadlock appears somewhere in max732x probe function.

Deadlock caught by lockdep (from kernel log):
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>>>>>>>>>
[    0.473419] ======================================================
[    0.473419] [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ]
[    0.473449] 3.x.xx-xxxxx-xxxxxxxx-dirty #2 Tainted: G        W
[    0.473449] ------------------------------------------------------
[    0.473449] swapper/0/1 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
[    0.473449]  (&lock->wait_lock){+.+...}, at: [<c072e350>] rt_mutex_trylock+0xc/0x74
[    0.473480]
[    0.473480] and this task is already holding:
[    0.473510]  (&chip->lock){......}, at: [<c0314514>] max732x_gpio_set_value+0x2c/0xa4
[    0.473541] which would create a new lock dependency:
[    0.473541]  (&chip->lock){......} -> (&lock->wait_lock){+.+...}

...

[    0.474273]  *** DEADLOCK ***
[    0.474273]
[    0.474273] 5 locks held by swapper/0/1:
[    0.474273]  #0:  (&__lockdep_no_validate__){......}, at: [<c03b2328>] __driver_attach+0x48/0x98
[    0.474304]  #1:  (&__lockdep_no_validate__){......}, at: [<c03b2338>] __driver_attach+0x58/0x98
[    0.474334]  #2:  (&chip->irq_lock){+.+...}, at: [<c0313e3c>] max732x_irq_bus_lock+0x14/0x20
[    0.474365]  #3:  (&irq_desc_lock_class){-.....}, at: [<c00a65a4>] __irq_get_desc_lock+0x48/0x88
[    0.474365]  #4:  (&chip->lock){......}, at: [<c0314514>] max732x_gpio
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< cut here >>>>>>>>>>>>>>>>>>>>>>>>>>>

Signed-off-by: Semen Protsenko <semen.protsenko@globallogic.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
drivers/gpio/gpio-max732x.c