From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 173A9359A80; Tue, 3 Mar 2026 22:44:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772577861; cv=none; b=FTjhda8M+hJaiTIip7q7DLzov67TF7roURtXWotwNrq4Nn6+BV0bBz6i3LYgf8sl64ioABl5u4wy79TPQ7da+Vs1CBaWZ6mB6h2XQWfezAYYiRObMDSzkUV6tiNKisgkXtaulvT/bGofiq2uypzXEZbXbMCmKnU/pqgB8TSAjbU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772577861; c=relaxed/simple; bh=4Ih/2o/t9doKo62D+kFikmb1MNMCyvP4c2VW3hJ0Kmc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=VWc3bidJZRZ5mrIXxwMc1xALJRAUOoXo99AwvL8sddODzXLpPvrkCqjCztKgoABJqQPrWi0fOXh1RPiJ7r5+3bSF1+1rMhDUOgjpiWlpcNqzMZgMn3LBV2TkwzLes+41RBVpt7UZNdxDEYnvMSkCv1Pt3MpURQAZgEhJGfYRKbs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id D3ED0140107; Tue, 3 Mar 2026 22:44:09 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf19.hostedemail.com (Postfix) with ESMTPA id 530B220028; Tue, 3 Mar 2026 22:44:07 +0000 (UTC) Date: Tue, 3 Mar 2026 17:44:42 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , Thomas Gleixner , Peter Zijlstra , Brian Geffon , John Stultz , Ian Rogers , Suleiman Souhlal Subject: [PATCH 3/2] tracing: Show TID and flags for PI futex system call trace event Message-ID: <20260303174442.548b6524@gandalf.local.home> In-Reply-To: <20260303214735.002154462@kernel.org> References: <20260303214735.002154462@kernel.org> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 530B220028 X-Rspamd-Server: rspamout06 X-Stat-Signature: 8s5yqswghkyr3p1j18bswtjszc6m3hu4 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX199QX2aqCE6wlXIzurzdMJRFtW9F45R+pU= X-HE-Tag: 1772577847-32625 X-HE-Meta: U2FsdGVkX18yDN8+OAhsaIQqgqHZeika6QDM1Ooh57Z4i4MlA89QFDkWFkGnCB7qM6srYmrasfQ01NhhBDlSad8X3a/hAiddu0a1AJR2eUGmb0eBmeNaKXW79XhkIaiwZ1Z7Bg2V1Qtbo5Jxz6j9FjaoxQRFFgL6z4yED14vzORZtKX49Ah8OWWbDh5lkPAVNjEhnMnU4YzOVk8EgIt7Sr7QY/PCK4rI2Tlrs0toiHau4LDdXwdKOAsBOtOR6St5ARBNYq57IwBUvdwRWN1iaz2znUBUJq6xqc/dCgmiLPCQSMTETDYMjonU/Z8p6FuIB9Hint6Un0fUA9YLI8GH+ydUq+SwYFhHCG0WJ0dEkvVpFFbAC2GoKsuRKRfzdxRH From: Steven Rostedt For the futex system call trace event for FUTEX_LOCK_PI and FUTEX_UNLOCK_PI commands, show the TID from the value (which is usually in hex) as well as translate the flags (DIED and WAITERS). pi_mutex_hammer-1098 [000] ..... 121.876928: sys_futex(uaddr: 0x560f40cc8180 (0x450) tid: 1104, FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7f2f9d4b1e50 (0.000100000)) pi_mutex_hammer-1128 [000] ..... 121.877120: sys_futex(uaddr: 0x560f40cc8180 (0x8000042a) tid: 1066 (WAITERS), FUTEX_LOCK_PI|FUTEX_PRIVATE_FLAG, val: 0, timespec: 0x7f2f8e493e50 (0.000100000)) pi_mutex_hammer-1106 [000] ..... 121.877242: sys_futex(uaddr: 0x560f40cc8180 (0x80000452) tid: 1106 (WAITERS), FUTEX_UNLOCK_PI|FUTEX_PRIVATE_FLAG, val: 0) This makes it easier to see the hand off of a mutex and who the owner was. Signed-off-by: Steven Rostedt (Google) --- kernel/trace/trace_syscalls.c | 25 +++++++++++++++++++++++-- 1 file changed, 23 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index d128dcb218a7..b3eddfee1a6b 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -300,6 +300,9 @@ sys_enter_futex_print(struct syscall_trace_enter *trace, struct syscall_metadata trace_seq_printf(s, "%s(", entry->name); + op = trace->args[1]; + cmd = op & FUTEX_CMD_MASK; + for (i = 0; !done && i < entry->nb_args; i++) { if (trace_seq_has_overflowed(s)) @@ -314,11 +317,29 @@ sys_enter_futex_print(struct syscall_trace_enter *trace, struct syscall_metadata trace_seq_printf(s, " (%u)", val); else trace_seq_printf(s, " (0x%x)", val); + + switch(cmd) { + case FUTEX_LOCK_PI: + case FUTEX_UNLOCK_PI: + trace_seq_printf(s, " tid: %d", val & FUTEX_TID_MASK); + + if (!(val & (FUTEX_OWNER_DIED|FUTEX_WAITERS))) + break; + + trace_seq_puts(s, " ("); + if (val & FUTEX_WAITERS) + trace_seq_puts(s, "WAITERS"); + if (val & FUTEX_OWNER_DIED) { + if (op & FUTEX_WAITERS) + trace_seq_putc(s, '|'); + trace_seq_puts(s, "DIED"); + } + trace_seq_putc(s, ')'); + break; + } } continue; case 1: - op = trace->args[i]; - cmd = op & FUTEX_CMD_MASK; if (cmd <= FUTEX_LOCK_PI2) trace_seq_printf(s, ", %s", __futex_cmds[cmd]); else -- 2.51.0