From nobody Sun Jan 11 19:23:00 2026 X-Original-To: dev-commits-src-branches@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4dq5510Tccz6NPHk for ; Sun, 11 Jan 2026 19:23:01 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R13" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4dq55061KPz3htd for ; Sun, 11 Jan 2026 19:23:00 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1768159380; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=qucoWpOHbV0e6lBJwVVqlZZ+cBMkLeOAVmg6hRXYA7o=; b=ehC9a8lmCfrWdKykjsUEk1UhB/siMT+rrpjhlsVVw1x70JaMSLbbJKurVs2WbNs0iU6CZs w3QuaPfaKFaaQcENGu5NbXKszNKJjCMN2v4sT6WNDElFo70kZRf4LpgoPglxLFeAUlrmfC NFFx+8rsCehBPtMpy2pELmeV5qI0hTLxptjuqJSgugISuckbWn9jEJozD+MJ7XwfUvmRHi RxsQFbnBax30kZ9wChbuav14IDXNs7BfYXWRvIWmrUQ+cKkWApU9gT2qTO37stPIoYAewN N+er5+lwVbSBm8kdZJ6gz3Bn6QAv7mmQd8qAYs05rEmgHiNP1CLF4c5d6KggmA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1768159380; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=qucoWpOHbV0e6lBJwVVqlZZ+cBMkLeOAVmg6hRXYA7o=; b=rv7CooE+F0neWVdMAZPgBCdC+OZHN6C/VUkgAJHIlWceWvnv2xewYBnxx3I/Uz4JgiIDK4 K0p5FSAqH+oSDweO41dwgTe93OyDUrtwrZ3Wiy3YaUspjW4je0l09JEz/dq0G5eXErfFqZ SkDSs4NEkSk2XF8tfzcLYRqgU1ai8HtqtV+Fh7omqhv2xdIUjJXdqE6CcrHm3J8PmcCLqo KLWGjUIBytq2aTffpVUFmJ4q8k84vcmQi6j6+u7bAXVFVZnbBheUfLOu3RL7rV0DONh32S KG6yTzgtbj7/PHdAD4HcmJ9rHID4f6k1EbIFd/rSAIflraoaX+5JiVZoIzUTaA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1768159380; a=rsa-sha256; cv=none; b=oxVVQjy/TrnepU8BfN8tYGtimW3dGTrDtgRBlilXj4oMuRSXhaVV4oZbCOavGpThAhSHGd FlcAl20LfJeA3f2OVuK9RqM/J0lE+LOcjBWdXCq3E5O1PwZIfrNtKnTboW7XpUgGJ53axb vFLYiA/PnmqsrJ4mDdjt8m5cUgRx/5Ukv2YkiKq4ZAcU5aDuTuKxSuOVIHjOR5M0OhK1dL PkE035jzdWDxwK1KUle7c23aYAdhvWE6jCkV7zZN9m7bs8hmJ1NloDyKOhKfn4b/A7E8bR flaZqXaDE2I9hdQTmC73MDf+14aISWcWhkhBrzRhzCpje668+eUJZbT1MXc1LA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4dq5505Skwzt7Q for ; Sun, 11 Jan 2026 19:23:00 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 3d6c2 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Sun, 11 Jan 2026 19:23:00 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Adrian Chadd Subject: git: a50789d8b89b - stable/15 - powerpc: put the isync inside the TD_LOCK() checking loop List-Id: Commits to the stable branches of the FreeBSD src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-branches List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-branches@freebsd.org Sender: owner-dev-commits-src-branches@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: adrian X-Git-Repository: src X-Git-Refname: refs/heads/stable/15 X-Git-Reftype: branch X-Git-Commit: a50789d8b89bd32199c6a9bf75b48ed8dee1e70d Auto-Submitted: auto-generated Date: Sun, 11 Jan 2026 19:23:00 +0000 Message-Id: <6963f894.3d6c2.4880f123@gitrepo.freebsd.org> The branch stable/15 has been updated by adrian: URL: https://cgit.FreeBSD.org/src/commit/?id=a50789d8b89bd32199c6a9bf75b48ed8dee1e70d commit a50789d8b89bd32199c6a9bf75b48ed8dee1e70d Author: Adrian Chadd AuthorDate: 2026-01-03 22:52:14 +0000 Commit: Adrian Chadd CommitDate: 2026-01-11 19:21:52 +0000 powerpc: put the isync inside the TD_LOCK() checking loop Fix a narrow window where the lock is unlocked but the checking CPU hasn't flushed things appropriately. Inside this window the CPU inside cpu_switch() will loop forever thinking the destination thread is still blocked/locked even though it is not. This manifests as the system hanging after starting all APs. I've seen this reliably trigger in qemu-system-ppc64 running power9 pseries guests; the more CPUs the more likely it triggers at boot. PR: kern/292167 Differential Revision: https://reviews.freebsd.org/D54478 Reviewed by: jhibbits MFC after: 1 week Relnotes: yes (cherry picked from commit 8df2e542146801fd01675e56724eaa567d04c209) --- sys/powerpc/powerpc/swtch32.S | 2 +- sys/powerpc/powerpc/swtch64.S | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/sys/powerpc/powerpc/swtch32.S b/sys/powerpc/powerpc/swtch32.S index 547e1c5a201b..ef1a397bf74d 100644 --- a/sys/powerpc/powerpc/swtch32.S +++ b/sys/powerpc/powerpc/swtch32.S @@ -141,8 +141,8 @@ cpu_switchin: blocked_loop: lwz %r7,TD_LOCK(%r2) cmpw %r6,%r7 - beq- blocked_loop isync + beq- blocked_loop #endif lwz %r17,TD_PCB(%r2) /* Get new current PCB */ diff --git a/sys/powerpc/powerpc/swtch64.S b/sys/powerpc/powerpc/swtch64.S index 5f80751c8a10..ba37274d32bb 100644 --- a/sys/powerpc/powerpc/swtch64.S +++ b/sys/powerpc/powerpc/swtch64.S @@ -194,8 +194,8 @@ cpu_switchin: blocked_loop: ld %r7,TD_LOCK(%r13) cmpd %r6,%r7 - beq- blocked_loop isync + beq- blocked_loop #endif ld %r17,TD_PCB(%r13) /* Get new PCB */