• Fabio Estevam's avatar
    ARM: imx: gpc: Fix the imx_gpc_genpd_init() error path · f9d1f7a7
    Fabio Estevam authored
    If of_genpd_add_provider_onecell() fails the following kernel crash is
    observed on a kernel built with multi_v7_defconfig:
    
    [    1.739301] [00000040] *pgd=00000000
    [    1.739310] Internal error: Oops: 5 [#1] SMP ARM
    [    1.739319] Modules linked in:
    [    1.739328] CPU: 1 PID: 95 Comm: kworker/1:4 Not tainted 4.8.0-11897-g6b5e09a7 #1
    [    1.739331] Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
    [    1.739352] Workqueue: pm genpd_power_off_work_fn
    [    1.739356] task: ee63d400 task.stack: ee70a000
    [    1.739365] PC is at mutex_lock+0xc/0x4c
    [    1.739374] LR is at regulator_disable+0x2c/0x60
    [    1.739379] pc : [<c0bc0da0>]    lr : [<c06e4b10>]    psr: 60000013
    [    1.739379] sp : ee70beb0  ip : 10624dd3  fp : ee6e6280
    [    1.739382] r10: eefb0900  r9 : 00000000  r8 : c1309918
    [    1.739385] r7 : 00000000  r6 : 00000040  r5 : 00000000  r4 : 00000040
    [    1.739390] r3 : 0000004c  r2 : 7fffd540  r1 : 000001e4  r0 : 00000040
    
    Instead of returning of_genpd_add_provider_onecell() directly,
    we should check its return value and in the case of error we
    should unwind the previously taken actions, which in these case are:
    - Call imx6q_pm_pu_power_off()
    - Set imx6q_pu_domain.reg back to NULL
    
    Setting imx6q_pu_domain.reg to NULL in the error case is important
    as it will prevent further operations in the pu_reg regulator.
    
    This kernel crash is not observed with imx_v6_v7_defconfig because
    it selects GPU and VPU drivers, which are consumers of the GPC block
    and thus change the refcount of the pu_reg regulator.
    Signed-off-by: default avatarFabio Estevam <fabio.estevam@nxp.com>
    Signed-off-by: default avatarShawn Guo <shawnguo@kernel.org>
    f9d1f7a7
gpc.c 11.3 KB