Commits
Grygorii Strashko committed fe8291e82b5
ARM: OMAP2+: omap-device: fix race deferred probe of omap_hsmmc vs omap_device_late_init
Kernel fails to boot 50% of times (form build to build) with
RT-patchset applied due to the following race - on late boot
stages deferred_probe_work_func->omap_hsmmc_probe races with omap_device_late_ini.
The same issue has been reported now on linux-next (4.3) by Keerthy [1]
late_initcall
- deferred_probe_initcal() tries to re-probe all pending driver's probe.
- later on, some driver is probing in this case It's cpsw.c
(but could be any other drivers)
cpsw_init
- platform_driver_register
- really_probe
- driver_bound
- driver_deferred_probe_trigger
and boot proceed.
So, at this moment we have deferred_probe_work_func scheduled.
late_initcall_sync
- omap_device_late_init
- omap_device_idle
CPU1 CPU2
- deferred_probe_work_func
- really_probe
- omap_hsmmc_probe
- pm_runtime_get_sync
late_initcall_sync
- omap_device_late_init
if (od->_driver_status != BUS_NOTIFY_BOUND_DRIVER) {
if (od->_state == OMAP_DEVICE_STATE_ENABLED) {
- omap_device_idle [ops - IP is disabled]
- [fail]
- pm_runtime_put_sync
- omap_hsmmc_runtime_suspend [ooops!]
== log ==
omap_hsmmc 480b4000.mmc: unable to get vmmc regulator -517
davinci_mdio 48485000.mdio: davinci mdio revision 1.6
davinci_mdio 48485000.mdio: detected phy mask fffffff3
libphy: 48485000.mdio: probed
davinci_mdio 48485000.mdio: phy[2]: device 48485000.mdio:02, driver unknown
davinci_mdio 48485000.mdio: phy[3]: device 48485000.mdio:03, driver unknown
omap_hsmmc 480b4000.mmc: unable to get vmmc regulator -517
cpsw 48484000.ethernet: Detected MACID = b4:99:4c:c7:d2:48
cpsw 48484000.ethernet: cpsw: Detected MACID = b4:99:4c:c7:d2:49
hctosys: unable to open rtc device (rtc0)
omap_hsmmc 480b4000.mmc: omap_device_late_idle: enabled but no driver. Idling
ldousb: disabling
Unhandled fault: imprecise external abort (0x1406) at 0x00000000
[00000000] *pgd=00000000
Internal error: : 1406 [#1] PREEMPT SMP ARM
Modules linked in:
CPU: 1 PID: 58 Comm: kworker/u4:1 Not tainted 4.1.2-rt1-00467-g6da3c0a-dirty #5
Hardware name: Generic DRA74X (Flattened Device Tree)
Workqueue: deferwq deferred_probe_work_func
task: ee6ddb00 ti: edd3c000 task.ti: edd3c000
PC is at omap_hsmmc_runtime_suspend+0x1c/0x12c
LR is at _od_runtime_suspend+0xc/0x24
pc : [<c0471998>] lr : [<c0029590>] psr: a0000013
sp : edd3dda0 ip : ee6ddb00 fp : c07be540
r10: 00000000 r9 : c07be540 r8 : 00000008
r7 : 00000000 r6 : ee646c10 r5 : ee646c10 r4 : edd79380
r3 : fa0b4100 r2 : 00000000 r1 : 00000000 r0 : ee646c10
Flags: NzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel
Control: 10c5387d Table: 8000406a DAC: 00000015
Process kworker/u4:1 (pid: 58, stack limit = 0xedd3c218)
Stack: (0xedd3dda0 to 0xedd3e000)
dda0: ee646c70 ee646c10 c0029584 00000000 00000008 c0029590 ee646c70 ee646c10
ddc0: c0029584 c03adfb8 ee646c10 00000004 0000000c c03adff0 ee646c10 00000004
dde0: 0000000c c03ae4ec 00000000 edd3c000 ee646c10 00000004 ee646c70 00000004
de00: fa0b4000 c03aec20 ee6ddb00 ee646c10 00000004 ee646c70 ee646c10 fffffdfb
de20: edd79380 00000000 fa0b4000 c03aee90 fffffdfb edd79000 ee646c00 c0474290
de40: 00000000 edda24c0 edd79380 edc81f00 00000000 00000200 00000001 c06dd488
de60: edda3960 ee646c10 ee646c10 c0824cc4 fffffdfb c0880c94 00000002 edc92600
de80: c0836378 c03a7f84 ee646c10 c0824cc4 00000000 c0880c80 c0880c94 c03a6568
dea0: 00000000 ee646c10 c03a66ac ee4f8000 00000000 00000001 edc92600 c03a4b40
dec0: ee404c94 edc83c4c ee646c10 ee646c10 ee646c44 c03a63c4 ee646c10 ee646c10
dee0: c0814448 c03a5aa8 ee646c10 c0814220 edd3c000 c03a5ec0 c0814250 ee6be400
df00: edd3c000 c004e5bc ee6ddb01 00000078 ee6ddb00 ee4f8000 ee6be418 edd3c000
df20: ee4f8028 00000088 c0836045 ee4f8000 ee6be400 c004e928 ee4f8028 00000000
df40: c004e8ec 00000000 ee6bf1c0 ee6be400 c004e8ec 00000000 00000000 00000000
df60: 00000000 c0053450 2e56fa97 00000000 afdffbd7 ee6be400 00000000 00000000
df80: edd3df80 edd3df80 00000000 00000000 edd3df90 edd3df90 edd3dfac ee6bf1c0
dfa0: c0053384 00000000 00000000 c000f668 00000000 00000000 00000000 00000000
dfc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
dfe0: 00000000 00000000 00000000 00000000 00000013 00000000 f1fc9d7e febfbdff
[<c0471998>] (omap_hsmmc_runtime_suspend) from [<c0029590>] (_od_runtime_suspend+0xc/0x24)
[<c0029590>] (_od_runtime_suspend) from [<c03adfb8>] (__rpm_callback+0x24/0x3c)
[<c03adfb8>] (__rpm_callback) from [<c03adff0>] (rpm_callback+0x20/0x80)
[<c03adff0>] (rpm_callback) from [<c03ae4ec>] (rpm_suspend+0xe4/0x618)
[<c03ae4ec>] (rpm_suspend) from [<c03aee90>] (__pm_runtime_idle+0x60/0x80)
[<c03aee90>] (__pm_runtime_idle) from [<c0474290>] (omap_hsmmc_probe+0x6bc/0xa7c)
[<c0474290>] (omap_hsmmc_probe) from [<c03a7f84>] (platform_drv_probe+0x44/0xa4)
[<c03a7f84>] (platform_drv_probe) from [<c03a6568>] (driver_probe_device+0x170/0x2b4)
[<c03a6568>] (driver_probe_device) from [<c03a4b40>] (bus_for_each_drv+0x64/0x98)
[<c03a4b40>] (bus_for_each_drv) from [<c03a63c4>] (device_attach+0x70/0x88)
[<c03a63c4>] (device_attach) from [<c03a5aa8>] (bus_probe_device+0x84/0xac)
[<c03a5aa8>] (bus_probe_device) from [<c03a5ec0>] (deferred_probe_work_func+0x58/0x88)
[<c03a5ec0>] (deferred_probe_work_func) from [<c004e5bc>] (process_one_work+0x134/0x464)
[<c004e5bc>] (process_one_work) from [<c004e928>] (worker_thread+0x3c/0x4fc)
[<c004e928>] (worker_thread) from [<c0053450>] (kthread+0xcc/0xe4)
[<c0053450>] (kthread) from [<c000f668>] (ret_from_fork+0x14/0x2c)
Code: e594302c e593202c e584205c e594302c (e5932128)
---[ end trace 0000000000000002 ]---
The issue happens because omap_device_late_init() do not take into
account that some drivers are present, but their probes were not
finished successfully and where deferred instead. This is the valid
case, and omap_device_late_init() should not idle such devices.
To fix this issue, the value of omap_device->_driver_status field
should be checked not only for BUS_NOTIFY_BOUND_DRIVER (driver is
present and has been bound to device successfully), but also checked
for BUS_NOTIFY_BIND_DRIVER (driver about to be bound) - which means
driver is present and there was try to bind it to device.
[1] http://www.spinics.net/lists/arm-kernel/msg441880.html
Cc: Tero Kristo <t-kristo@ti.com>
Cc: Keerthy <j-keerthy@ti.com>
Tested-by: Keerthy <j-keerthy@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>