[Crash-utility] [RFC] display function param and local value for backtrace
Rabin Vincent
rabin at rab.in
Wed Oct 17 15:58:33 UTC 2012
2012/10/16 Lei Wen <leiwen at marvell.com>:
> Current I am trying to make crash support display out function param and
> local value while backtracing.
>
> The idea for this patch is to mimic core dump support in gdb, teaching the
> crash to supply the regset to the gdb, so that gdb could have full knowledge
> what is going on in the panic point.
Just for comparison/inspiration, I'm attaching the patch I've been using
for some time now to get this information in crash. It enables gdb's
backtrace directly so you will need to run it with "backtrace" or "gdb
bt".
I've made no attempt to clean up the patch, it's as-is (hacky) and
applies on top of Crash 6.0.6. I've only tested it on ARM and there are
several rough edges even on ARM (example, observe the "request failed"
message after the successful trace).
It looks like this:
crash> set 533
crash> bt
PID: 533 TASK: e62d4560 CPU: 1 COMMAND: "kworker/u:2"
#0 [<c0648f14>] (__schedule) from [<c0649688>]
#1 [<c0649688>] (schedule) from [<c064a898>]
#2 [<c064a898>] (__mutex_lock_slowpath) from [<c064a98c>]
#3 [<c064a98c>] (mutex_lock) from [<c03171dc>]
#4 [<c03171dc>] (device_attach) from [<c03168fc>]
#5 [<c03168fc>] (bus_probe_device) from [<c03149dc>]
#6 [<c03149dc>] (device_add) from [<c040cd88>]
#7 [<c040cd88>] (sdio_add_func) from [<c040c060>]
#8 [<c040c060>] (mmc_attach_sdio) from [<c0404930>]
#9 [<c0404930>] (mmc_rescan) from [<c00bb5e4>]
#10 [<c00bb5e4>] (process_one_work) from [<c00bbaf4>]
#11 [<c00bbaf4>] (worker_thread) from [<c00c0564>]
#12 [<c00c0564>] (kthread) from [<c0064288>]
crash> gdb bt
#0 0xc0648f14 in context_switch (next=0xe49b6520, prev=0xe62d4560,
rq=0xc1b4a8c0) at /tmp/kernel/kernel/sched.c:3216
#1 __schedule () at /tmp/kernel/kernel/sched.c:4354
#2 0xc0649688 in schedule () at /tmp/kernel/kernel/sched.c:4406
#3 0xc064a898 in __mutex_lock_common (state=2, lock=0xe49f1c3c,
subclass=<optimized out>, nest_lock=<optimized out>, ip=<optimized
out>) at /tmp/kernel/kernel/mutex.c:244
#4 __mutex_lock_slowpath (lock_count=0xe49f1c3c) at
/tmp/kernel/kernel/mutex.c:405
#5 0xc064a98c in __mutex_fastpath_lock (fail_fn=0xc064a760
<__mutex_lock_slowpath>, count=0xe49f1c3c) at
/tmp/kernel/arch/arm/include/asm/mutex.h:43
#6 mutex_lock (lock=0xe49f1c3c) at /tmp/kernel/kernel/mutex.c:90
#7 0xc03171dc in device_lock (dev=0xe49f1c08) at
/tmp/kernel/include/linux/device.h:673
#8 device_attach (dev=0xe49f1c08) at /tmp/kernel/drivers/base/dd.c:246
#9 0xc03168fc in bus_probe_device (dev=<optimized out>) at
/tmp/kernel/drivers/base/bus.c:493
#10 0xc03149dc in device_add (dev=0xe49f1c08) at
/tmp/kernel/drivers/base/core.c:978
#11 0xc040cd88 in sdio_add_func (func=0xe49f1c00) at
/tmp/kernel/drivers/mmc/core/sdio_bus.c:315
#12 0xc040c060 in mmc_attach_sdio (host=0xe6486800) at
/tmp/kernel/drivers/mmc/core/sdio.c:1197
#13 0xc0404930 in mmc_rescan_try_freq (freq=<optimized out>,
host=0xe6486800) at /tmp/kernel/drivers/mmc/core/core.c:2069
#14 mmc_rescan (work=0xe6486a08) at /tmp/kernel/drivers/mmc/core/core.c:2188
#15 0xc00bb5e4 in process_one_work (worker=0xe62e04e0,
work=0xe6486a08) at /tmp/kernel/kernel/workqueue.c:1870
#16 0xc00bbaf4 in worker_thread (__worker=0xe62e04e0) at
/tmp/kernel/kernel/workqueue.c:1981
#17 0xc00c0564 in kthread (_create=0xe60a9ec4) at
/tmp/kernel/kernel/kthread.c:96
#18 0xc0064288 in kernel_thread_helper ()
Register 25 is not available
gdb: gdb request failed: bt
crash> gdb bt full
#0 0xc0648f14 in context_switch (next=0xe49b6520, prev=0xe62d4560,
rq=0xc1b4a8c0) at /tmp/kernel/kernel/sched.c:3216
mm = 0x0
oldmm = <optimized out>
#1 __schedule () at /tmp/kernel/kernel/sched.c:4354
prev = 0xe62d4560
next = 0xe49b6520
switch_count = <optimized out>
rq = 0xc1b4a8c0
cpu = <optimized out>
#2 0xc0649688 in schedule () at /tmp/kernel/kernel/sched.c:4406
tsk = <unavailable>
#3 0xc064a898 in __mutex_lock_common (state=2, lock=0xe49f1c3c,
subclass=<optimized out>, nest_lock=<optimized out>, ip=<optimized
out>) at /tmp/kernel/kernel/mutex.c:244
task = 0xe62d4560
waiter = {
list = {
next = 0xe49f1c48,
prev = 0xe49f1c48
},
task = 0xe62d4560
}
#4 __mutex_lock_slowpath (lock_count=0xe49f1c3c) at
/tmp/kernel/kernel/mutex.c:405
lock = 0xe49f1c3c
#5 0xc064a98c in __mutex_fastpath_lock (fail_fn=0xc064a760
<__mutex_lock_slowpath>, count=0xe49f1c3c) at
/tmp/kernel/arch/arm/include/asm/mutex.h:43
__ex_flag = <optimized out>
__res = <optimized out>
#6 mutex_lock (lock=0xe49f1c3c) at /tmp/kernel/kernel/mutex.c:90
No locals.
#7 0xc03171dc in device_lock (dev=0xe49f1c08) at
/tmp/kernel/include/linux/device.h:673
No locals.
#8 device_attach (dev=0xe49f1c08) at /tmp/kernel/drivers/base/dd.c:246
ret = 0
#9 0xc03168fc in bus_probe_device (dev=<optimized out>) at
/tmp/kernel/drivers/base/bus.c:493
bus = <optimized out>
ret = <optimized out>
#10 0xc03149dc in device_add (dev=0xe49f1c08) at
/tmp/kernel/drivers/base/core.c:978
parent = 0xe3c7e008
class_intf = <optimized out>
error = 0
__func__ = "device_add"
#11 0xc040cd88 in sdio_add_func (func=0xe49f1c00) at
/tmp/kernel/drivers/mmc/core/sdio_bus.c:315
ret = <unavailable>
#12 0xc040c060 in mmc_attach_sdio (host=0xe6486800) at
/tmp/kernel/drivers/mmc/core/sdio.c:1197
err = <optimized out>
i = <optimized out>
funcs = 2
ocr = 553647872
card = 0xe3c7e000
#13 0xc0404930 in mmc_rescan_try_freq (freq=<optimized out>,
host=0xe6486800) at /tmp/kernel/drivers/mmc/core/core.c:2069
No locals.
#14 mmc_rescan (work=0xe6486a08) at /tmp/kernel/drivers/mmc/core/core.c:2188
host = 0xe6486800
i = <optimized out>
#15 0xc00bb5e4 in process_one_work (worker=0xe62e04e0,
work=0xe6486a08) at /tmp/kernel/kernel/workqueue.c:1870
cwq = 0xe6344a00
gcwq = <optimized out>
bwh = <unavailable>
cpu_intensive = <optimized out>
f = 0xc04046e4 <mmc_rescan>
#16 0xc00bbaf4 in worker_thread (__worker=0xe62e04e0) at
/tmp/kernel/kernel/workqueue.c:1981
work = <optimized out>
worker = 0xe62e04e0
gcwq = 0xc09c0a60
#17 0xc00c0564 in kthread (_create=0xe60a9ec4) at
/tmp/kernel/kernel/kthread.c:96
create = 0xe60a9ec4
threadfn = 0xc00bb960 <worker_thread>
data = 0xe62e04e0
self = {
should_stop = 0,
data = 0xe62e04e0,
exited = {
done = 0,
wait = {
lock = {
{
rlock = {
raw_lock = {
lock = 0
},
break_lock = 0
}
}
},
task_list = {
next = 0xe62effd0,
prev = 0xe62effd0
}
}
}
}
ret = -4
#18 0xc0064288 in kernel_thread_helper ()
No symbol table info available.
Register 25 is not available
gdb: gdb request failed: bt full
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