On Tue, May 15, 2012 at 01:53:56PM +0800, Yong Zhang wrote: > From: Yong Zhang <yong.zhang@xxxxxxxxxxxxx> > > Otherwise there will be warning on ARM like below: > > WARNING: at build/linux/kernel/smp.c:459 smp_call_function_many+0x98/0x264() > Modules linked in: > [<c0013bb4>] (unwind_backtrace+0x0/0xe4) from [<c001be94>] (warn_slowpath_common+0x4c/0x64) > [<c001be94>] (warn_slowpath_common+0x4c/0x64) from [<c001bec4>] (warn_slowpath_null+0x18/0x1c) > [<c001bec4>] (warn_slowpath_null+0x18/0x1c) from [<c0053ff8>](smp_call_function_many+0x98/0x264) > [<c0053ff8>] (smp_call_function_many+0x98/0x264) from [<c0054364>] (smp_call_function+0x44/0x6c) > [<c0054364>] (smp_call_function+0x44/0x6c) from [<c0017d50>] (__new_context+0xbc/0x124) > [<c0017d50>] (__new_context+0xbc/0x124) from [<c009e49c>] (flush_old_exec+0x460/0x5e4) > [<c009e49c>] (flush_old_exec+0x460/0x5e4) from [<c00d61ac>] (load_elf_binary+0x2e0/0x11ac) > [<c00d61ac>] (load_elf_binary+0x2e0/0x11ac) from [<c009d060>] (search_binary_handler+0x94/0x2a4) > [<c009d060>] (search_binary_handler+0x94/0x2a4) from [<c009e8fc>] (do_execve+0x254/0x364) > [<c009e8fc>] (do_execve+0x254/0x364) from [<c0010e84>] (sys_execve+0x34/0x54) > [<c0010e84>] (sys_execve+0x34/0x54) from [<c000da00>] (ret_fast_syscall+0x0/0x30) > ---[ end trace 0000000000000002 ]--- > > The reason is that ARM need irq enabled when doing activate_mm(). > According to mm-protect-activate-switch-mm.patch, actually > preempt_[disable|enable]_rt() is sufficient. Frank Rowand posted a very similar fix in December of last year that we've been carrying to fix the same issue: http://permalink.gmane.org/gmane.linux.kernel/1229806 It looks like there was some deliberation as to whether or not it should be pulled into stable-rt. Perhaps its time to revisit this discussion? -- joshc -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
