Ftrace Worked After Disabling msm security feature

# CONFIG_STRICT_MEMORY_RWX is not set

Thanks
Dhyan

On Thursday, August 29, 2013 2:36:59 PM UTC+5:30, Dhyan wrote:
> 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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