2011/3/23 Steven Rostedt <rostedt@xxxxxxxxxxx>: > 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> Same for me: Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx> -- 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
