On 1/15/2018 4:32 PM, John Ogness wrote:
Hello Gaurav.
On 2018-01-09, Kohli, Gaurav <gkohli@xxxxxxxxxxxxxx> wrote:
We are seeing crash in do_task_stat while accessing stack pointer, It
seems same task has already completed do_exit call.
So it seems a race between them:
Below is the crash trace:
49750.534377] Kernel BUG at ffffff8e7a4c53a8 [verbose debug info
unavailable]
[49750.534394] task: ffffffe7b4475580 task.stack: ffffffe7a5f0c000
[49750.534400] PC is at do_task_stat+0x740/0x908
[49750.534402] LR is at do_task_stat+0xa4/0x908
[49750.534403] pc : [<ffffff8e7a4c53a8>] lr : [<ffffff8e7a4c4d0c>]
pstate: 80400145
[49750.534404] sp : ffffffe7a5f0fbd0
and here is stack trace on that core:
-000|user_stack_pointer(inline)
-000|do_task_stat(
| m = 0xFFFFFFE7A5CD7380,
| ns = 0xFFFFFF8E7C43C748,
| ?,
| task = 0xFFFFFFE80D8C2280,
| ?)
| tty_pgrp = 0
| ppid = 2084696064
| sid = 0
| mm = 0xFFFFFFE7B4424140
| tcomm = (84, 9, 71, 122, 142, 255, 255, 255, 48, 253, 240, 165,
231, 255, 255, 255)
| flags = 18446743969119403392
-001|proc_tgid_stat(
| m = 0xFFFFFFE7A5CD7380,
| ?,
Below are task stats which shows , process completed the do_exit call:
struct task_struct.flags -x 0xFFFFFFE80D8C2280
flags = 0x40870c
crash_64> struct task_struct.exit_code -x 0xFFFFFFE80D8C2280
exit_code = 0x6
struct task_struct.state -x 0xFFFFFFE80D8C2280
state = 0x40
I am confused why this task is in the TASK_PARKED state. What kind of
task is this?
Hi John,
This is android HAL layer service and also before bug, i am seeing lot of service exited in logs also,
although not seeing for this pid 6807
.452202: <2> init: starting service 'limits-hal-1-0'...
49749.460039: <2> init: property_set("ro.boottime.limits-hal-1-0", "61591320967789") failed: property already set
49749.607496: <6> sh (2422): drop_caches: 3
49750.281635: <6> sh (2422): drop_caches: 3
49750.533853: <2> init: Untracked pid 6811 exited with status 0
And why it is parked , that is not clear as state is already updated of task.
Regards
Gaurav
In our build both patches are there ,
fs/proc: report eip/esp in /prod/PID/stat for coredumping
and also task.state has already set PF_DUMPCORE as it got the sigabrt
signal.
John Ogness
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