From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0EEE91509AC; Tue, 20 Feb 2024 21:17:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708463828; cv=none; b=OE4GK5K1SqJs25kyuQP4RbYift4IN0DGUIemvmzfhs37EhV6teku8RBIL9GoSTfckP8Gei8SvC+CkUI3NtFgLqEqmjJu3sMhoBq1xnXA+00TczsKQuFkZl20cLoeNQm5u4byWPJA4DBEyOPRk62N8P6Hk15XSsn5RKCbLPLze6E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708463828; c=relaxed/simple; bh=LGCQAPF2WwPd2R1OHGbm07kTMMMHvgdhocjHmsyKqfw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hb7w1N+gvPoVVTuTSaYxKavj6n7+E2PuYptcZXydr0SfZjXwhqm9+a04MI4bCmQuTk/PtsvDfdj5ZP/5IWAI5hZe8Ehae4CY5nFc1Q8SYluTEbwWRkm8nBoMYFF0iYnCUBU//KvqG/FKYnnbJusMQ4M8YKGjLl9g3iT1d9LiYy0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BrwGanHP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BrwGanHP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B9F0C433F1; Tue, 20 Feb 2024 21:17:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1708463827; bh=LGCQAPF2WwPd2R1OHGbm07kTMMMHvgdhocjHmsyKqfw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BrwGanHPThymKo/WL1nMPTCNEIhcNFK2JWxdi0qR67c1pcJmEnFFX8qjBEOqCATL0 MO01CKv44qUkhv0G8biMz4VX0FhVwTv/xLEtDLtD5cUZcbfDkPSpFmo90u/6wNXEJm xNXaWodRYrmFONjQR6cz1Tz3wtXPQvkMZOs0n7Yo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Masami Hiramatsu , Mathieu Desnoyers , Daniel Bristot de Oliveira , "Steven Rostedt (Google)" Subject: [PATCH 6.6 148/331] tracing/timerlat: Move hrtimer_init to timerlat_fd open() Date: Tue, 20 Feb 2024 21:54:24 +0100 Message-ID: <20240220205642.200669067@linuxfoundation.org> X-Mailer: git-send-email 2.43.2 In-Reply-To: <20240220205637.572693592@linuxfoundation.org> References: <20240220205637.572693592@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daniel Bristot de Oliveira commit 1389358bb008e7625942846e9f03554319b7fecc upstream. Currently, the timerlat's hrtimer is initialized at the first read of timerlat_fd, and destroyed at close(). It works, but it causes an error if the user program open() and close() the file without reading. Here's an example: # echo NO_OSNOISE_WORKLOAD > /sys/kernel/debug/tracing/osnoise/options # echo timerlat > /sys/kernel/debug/tracing/current_tracer # cat < ./timerlat_load.py # !/usr/bin/env python3 timerlat_fd = open("/sys/kernel/tracing/osnoise/per_cpu/cpu0/timerlat_fd", 'r') timerlat_fd.close(); EOF # ./taskset -c 0 ./timerlat_load.py BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 1 PID: 2673 Comm: python3 Not tainted 6.6.13-200.fc39.x86_64 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39 04/01/2014 RIP: 0010:hrtimer_active+0xd/0x50 Code: 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 48 8b 57 30 <8b> 42 10 a8 01 74 09 f3 90 8b 42 10 a8 01 75 f7 80 7f 38 00 75 1d RSP: 0018:ffffb031009b7e10 EFLAGS: 00010286 RAX: 000000000002db00 RBX: ffff9118f786db08 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff9117a0e64400 RDI: ffff9118f786db08 RBP: ffff9118f786db80 R08: ffff9117a0ddd420 R09: ffff9117804d4f70 R10: 0000000000000000 R11: 0000000000000000 R12: ffff9118f786db08 R13: ffff91178fdd5e20 R14: ffff9117840978c0 R15: 0000000000000000 FS: 00007f2ffbab1740(0000) GS:ffff9118f7840000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000010 CR3: 00000001b402e000 CR4: 0000000000750ee0 PKRU: 55555554 Call Trace: ? __die+0x23/0x70 ? page_fault_oops+0x171/0x4e0 ? srso_alias_return_thunk+0x5/0x7f ? avc_has_extended_perms+0x237/0x520 ? exc_page_fault+0x7f/0x180 ? asm_exc_page_fault+0x26/0x30 ? hrtimer_active+0xd/0x50 hrtimer_cancel+0x15/0x40 timerlat_fd_release+0x48/0xe0 __fput+0xf5/0x290 __x64_sys_close+0x3d/0x80 do_syscall_64+0x60/0x90 ? srso_alias_return_thunk+0x5/0x7f ? __x64_sys_ioctl+0x72/0xd0 ? srso_alias_return_thunk+0x5/0x7f ? syscall_exit_to_user_mode+0x2b/0x40 ? srso_alias_return_thunk+0x5/0x7f ? do_syscall_64+0x6c/0x90 ? srso_alias_return_thunk+0x5/0x7f ? exit_to_user_mode_prepare+0x142/0x1f0 ? srso_alias_return_thunk+0x5/0x7f ? syscall_exit_to_user_mode+0x2b/0x40 ? srso_alias_return_thunk+0x5/0x7f ? do_syscall_64+0x6c/0x90 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7f2ffb321594 Code: 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 80 3d d5 cd 0d 00 00 74 13 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 3c c3 0f 1f 00 55 48 89 e5 48 83 ec 10 89 7d RSP: 002b:00007ffe8d8eef18 EFLAGS: 00000202 ORIG_RAX: 0000000000000003 RAX: ffffffffffffffda RBX: 00007f2ffba4e668 RCX: 00007f2ffb321594 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007ffe8d8eef40 R08: 0000000000000000 R09: 0000000000000000 R10: 55c926e3167eae79 R11: 0000000000000202 R12: 0000000000000003 R13: 00007ffe8d8ef030 R14: 0000000000000000 R15: 00007f2ffba4e668 CR2: 0000000000000010 ---[ end trace 0000000000000000 ]--- Move hrtimer_init to timerlat_fd open() to avoid this problem. Link: https://lore.kernel.org/linux-trace-kernel/7324dd3fc0035658c99b825204a66049389c56e3.1706798888.git.bristot@kernel.org Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: stable@vger.kernel.org Fixes: e88ed227f639 ("tracing/timerlat: Add user-space interface") Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_osnoise.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c index bd0d01d00fb9..a8e28f9b9271 100644 --- a/kernel/trace/trace_osnoise.c +++ b/kernel/trace/trace_osnoise.c @@ -2444,6 +2444,9 @@ static int timerlat_fd_open(struct inode *inode, struct file *file) tlat = this_cpu_tmr_var(); tlat->count = 0; + hrtimer_init(&tlat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); + tlat->timer.function = timerlat_irq; + migrate_enable(); return 0; }; @@ -2526,9 +2529,6 @@ timerlat_fd_read(struct file *file, char __user *ubuf, size_t count, tlat->tracing_thread = false; tlat->kthread = current; - hrtimer_init(&tlat->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD); - tlat->timer.function = timerlat_irq; - /* Annotate now to drift new period */ tlat->abs_period = hrtimer_cb_get_time(&tlat->timer); -- 2.43.2