On Wed, 2011-03-23 at 22:29 +0900, Namhyung Kim wrote: > The %pT format specifier is for stack backtrace. Its handler > sprint_trace() does symbol lookup using (address-1) to ensure > the address will not point outside of the function. > > If there is a tail-call to the function marked "noreturn", > gcc optimized out the code after the call then causes saved > return address points outside of the function (i.e. the start > of the next function), so pollutes call trace somewhat. > This patch will fix it. > > before: > [ 18.345923] Call Trace: > [ 18.346001] [<ffffffff812a8502>] panic+0x8c/0x18d > [ 18.346257] [<ffffffffa000012a>] deep01+0x0/0x38 [test_panic] <--- bad > [ 18.346347] [<ffffffff81104666>] proc_file_write+0x73/0x8d > [ 18.346432] [<ffffffff811000b3>] proc_reg_write+0x8d/0xac > [ 18.346516] [<ffffffff810c7d32>] vfs_write+0xa1/0xc5 > [ 18.346603] [<ffffffff810c7e0f>] sys_write+0x45/0x6c > [ 18.346801] [<ffffffff8f02943b>] system_call_fastpath+0x16/0x1b > > after: > [ 22.224483] Call Trace: > [ 22.224569] [<ffffffff812bce69>] panic+0x8c/0x18d > [ 22.224848] [<ffffffffa000012a>] panic_write+0x20/0x20 [test_panic] <--- ok > [ 22.224979] [<ffffffff81115fab>] proc_file_write+0x73/0x8d > [ 22.225089] [<ffffffff81111a5f>] proc_reg_write+0x8d/0xac > [ 22.225199] [<ffffffff810d90ee>] vfs_write+0xa1/0xc5 > [ 22.225304] [<ffffffff810d91cb>] sys_write+0x45/0x6c > [ 22.225408] [<ffffffff812c07fb>] system_call_fastpath+0x16/0x1b Nice Acked-by: Steven Rostedt <rostedt@xxxxxxxxxxx> -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
