From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792555759; b=FXB+RaX10bjUFQuofRcVEyIWshQtQ7e2JsgQ8hG93HUeisiDzKKLCYEaVLnJsQsSP111 oCbtbFvcAGDZBrQCyuhOGwT4Aa0p+ZmrS1jc46zun45ABnUDPKBoUw7vTxvqXaOLNtpHm dvWRrKvgD2mW7SOa/333igkYNdExtfGV8kOhQu/wqJ52fO5uHJDj3CKuDTOO5GhwppHPC 1g8amXLHHzj8QBimyNSlnYNbycTw79p7YOtRsX4X40Jkv6/TufgErCVsSYcE87cHPJHFw fPK0DEjDfulZeIYlZPCt13j03PlFcGDfzWahdBzSElm/g5VBFa2Pz0XVySeAIFfxoWQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792555759; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=73sIXLKTwtG8bQRdXGMaGOTBn3Y0qk223b3F6B2LH9k=; b=NtqwEneZ1SLZlwHcfO3kiY1aYE/Y8/spO+NRWKW7n0QcgLi7VmNGZFBsNo0am6RnNJ3+ E/x+aGKFzPeVwP7KdES71/SNoMlPwiZ6R9vVd4EroJF4GCUmP8u95WJweHeAVN8cySvYh wIdi86QM2znzT1vFBhZFRfFRBf1uy8FjU8wjiyNCspOAilQtktEu3ukwwJVJZV7HvrpF1 sBcptjm6EKRQ8Hj7eX3Wmy0yAo6MmiHNgVSgkrIeC1oPtpgrTdvtAQ7sLwSD/QuaHOUDk 1EoB51JUKRRJSyb7Pr3osVdPrkQdHb4f2DcwgfRqUIcHKaDdOvi5ENBV61ZiP7s8O3w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=pthUGAIx; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A868A606A319 for ; Wed, 21 Oct 2026 04:09:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=pthUGAIx Received: by smtp.kernel.org (Postfix) with ESMTPSA id 288A21F000C9; Wed, 21 Oct 2026 04:09:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1792555758; bh=73sIXLKTwtG8bQRdXGMaGOTBn3Y0qk223b3F6B2LH9k=; h=Date:To:From:Subject; b=pthUGAIxE5caxUUzReNAe8PDl5o4/sAvXPba0+E59YJyJdol7DPC4ChmXqaAficwl SG2/W5I31XYpd6hZyc9W0cl/4sr8RYtdK4VYivoatwogUEzXX1o3C4Fb59TXb66zsx NcF33LjguOryKN8UjNkgOH0kcq+a+WGFMCQich+I= Date: Tue, 20 Oct 2026 21:09:17 -0700 To: mm-commits@vger.kernel.org,tfiga@chromium.org,senozhatsky@chromium.org,pmladek@suse.com,dianders@chromium.org,brads@mainlining.org,tzungbi@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + watchdog-force-console-verbose-when-reporting-lockups.patch added to mm-nonmm-unstable branch Message-Id: <20261021040918.288A21F000C9@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The patch titled Subject: watchdog: force console verbose when reporting lockups has been added to the -mm mm-nonmm-unstable branch. Its filename is watchdog-force-console-verbose-when-reporting-lockups.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/watchdog-force-console-verbose-when-reporting-lockups.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Tzung-Bi Shih Subject: watchdog: force console verbose when reporting lockups Date: Wed, 07 Oct 2026 05:17:26 +0000 When a hard or soft lockup is detected, the watchdog prints a header at KERN_EMERG (<0>), followed by diagnostic details (modules, registers, and backtraces) at KERN_WARNING/KERN_DEFAULT (<4>) and KERN_INFO (<6>). If console_loglevel is quiet (<= 4), the console skips those <4>/<6> diagnostic messages before vpanic() has a chance to call console_verbose(). With the buddy detector, this leaves only the detector CPU's panic stack on the console and nothing about the locked CPU: <0>[ 1535.991833][ C6] watchdog: Watchdog detected hard LOCKUP on cpu 7 <0>[ 1535.995960][ C6] Kernel panic - not syncing: Hard LOCKUP <4>[ 1535.995970][ C6] CPU: 6 UID: 0 PID: 0 Comm: swapper/6 ... <4>[ 1535.995997][ C6] Call trace: ... <4>[ 1535.996063][ C6] watchdog_hardlockup_check+0x1e0/0x288 <4>[ 1535.996075][ C6] watchdog_buddy_check_hardlockup+0xb4/0xc0 Similar to commit 168e06f7937d ("kernel/hung_task.c: force console verbose before panic"), call console_verbose() before printing the lockup report so the diagnostic output is not suppressed. Link: https://lore.kernel.org/20261007051726.4154849-1-tzungbi@kernel.org Signed-off-by: Tzung-Bi Shih Signed-off-by: Andrew Morton Reviewed-by: Sergey Senozhatsky Reviewed-by: Bradley Morgan Tested-by: Bradley Morgan # Power10 / ARM64 Reviewed-by: Douglas Anderson Cc: Petr Mladek Cc: Tomasz Figa --- kernel/watchdog.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) --- a/kernel/watchdog.c~watchdog-force-console-verbose-when-reporting-lockups +++ a/kernel/watchdog.c @@ -255,6 +255,9 @@ void watchdog_hardlockup_check(unsigned return; } + if (hardlockup_panic) + console_verbose(); + /* * NOTE: we call printk_cpu_sync_get_irqsave() after printing * the lockup message. While it would be nice to serialize @@ -880,6 +883,10 @@ static enum hrtimer_restart watchdog_tim /* Start period for the next softlockup warning. */ update_report_ts(); + thresh_count = duration / get_softlockup_thresh(); + if (softlockup_panic && thresh_count >= softlockup_panic) + console_verbose(); + printk_cpu_sync_get_irqsave(flags); pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n", smp_processor_id(), duration, @@ -901,7 +908,6 @@ static enum hrtimer_restart watchdog_tim add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK); sys_info(softlockup_si_mask & ~SYS_INFO_ALL_BT); - thresh_count = duration / get_softlockup_thresh(); if (softlockup_panic && thresh_count >= softlockup_panic) panic("softlockup: hung tasks"); _ Patches currently in -mm which might be from tzungbi@kernel.org are watchdog-force-console-verbose-when-reporting-lockups.patch