Dear all,
I am trying to run ftrace in nexus-4 with B2G.But when i enable ftrace i am
getting following warning during bootup
<4>[ 0.036654] ------------[ cut here ]------------
<4>[ 0.036685] WARNING: at kernel/trace/ftrace.c:1590 ftrace_bug+0xf0/0x178()
<4>[ 0.036716] [<c00150ac>] (unwind_backtrace+0x0/0xec) from [<c085322c>]
(dump_stack+0x20/0x24)
<4>[ 0.036746] [<c085322c>] (dump_stack+0x20/0x24) from [<c0070db0>]
(warn_slowpath_common+0x58/0x70)
<4>[ 0.036777] [<c0070db0>] (warn_slowpath_common+0x58/0x70) from
[<c0070ec0>] (warn_slowpath_null+0x2c/0x34)
<4>[ 0.036807] [<c0070ec0>] (warn_slowpath_null+0x2c/0x34) from [<c00d34b4>]
(ftrace_bug+0xf0/0x178)
<4>[ 0.036868] [<c00d34b4>] (ftrace_bug+0xf0/0x178) from [<c0d145d8>]
(ftrace_init+0x364/0x50c)
<4>[ 0.036899] [<c0d145d8>] (ftrace_init+0x364/0x50c) from [<c0d00944>]
(start_kernel+0x42c/0x498)
<4>[ 0.036929] [<c0d00944>] (start_kernel+0x42c/0x498) from [<8020803c>]
(0x8020803c)
<4>[ 0.036960] ---[ end trace da227214a82491b7 ]---
<6>[ 0.036990] ftrace faulted on writing [<c010000c>]
is_pageblock_removable_nolock+0x10/0xcc
And i checked little more and found
probe_kernel_write () throwing EPERM error
kernel/trace/ftrace.c
|
|__ ftrace_init(void)
|
|_ftrace_process_locs
|
|_ ftrace_update_code
|
|_ftrace_code_disable
|
|_ ftrace_make_nop() -arch/arm/kernel/ftrace.c
|
|_ftrace_modify_code
|
|__probe_kernel_write ()
And ftrace faulted on writing address c010000c is from mm/page_alloc.c ,bool
is_pageblock_removable_nolock(struct page *page)
But I am not able to find out why ftrace faulted error is coming ?
Can some one help ?
Thanks
Dhyan
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