From nobody Sun Jan 4 02:28:06 2026 X-Original-To: dev-commits-src-main@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 4dkLvB3vrJz6MGTm for ; Sun, 04 Jan 2026 02:28:06 +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 4dkLvB33vTz3WyF for ; Sun, 04 Jan 2026 02:28:06 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1767493686; 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=oJjXdWeKIBVNz8SBQBnJ4GhjCcc8yAbDzM0tUgopB2M=; b=ZoZwsAR5YODOKdJsMDqYhuVf5GT6CC7byJTCL/nNkxKn5+s9O2ULijCk1oY5XlL2ui86bE QNqkST6KmrlTK2Cg0YYX+AZXbLFC4V7b+SzewOnbMDAoaEFtiM8rLwg7O091zGnTQy3oj1 kqnhx6iEySiRP4KpaQAsIziCxDFcf1DdR7EQXe4ufwsZ9ehv5fdCYjkKWUy2UIgeh0qTZz 9uwSeAlfDAxcdKpvZwDrDEWKVk9wY80DxKVUNLMJCF00DmEMdxVRrYf/Sa/NCYuDn6vYfd kfrUC5BOlqYDPdmn/Hjd1vB2bXdHqL6ZIUoK4rdtkpDcoZdCmTSW9Rd2ndw3cQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1767493686; 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=oJjXdWeKIBVNz8SBQBnJ4GhjCcc8yAbDzM0tUgopB2M=; b=JXNeWLV7bA6tKnm5lul9x6dePnJfyX5SPox7qpFspmFasf7jFrJNKgdXNdPElJXw9Z4+rd Drh0fiXkuuIvhRKF+205XOUZxdHj4U26OR8mYsO3p+kg3xEaA2iIdS1od1s/LqK5XyBZ3+ Iz8W1i+rJip2QK+T3c/MR5wFvz5AGHx1x+OVO/tFF5H0ZILs+q/c1ZAP/hVla9X+Nu1+in zxwLpJfe0nlEviHVhEZ5mdZ9NlK9S5Y8cir/2YrG9qJTL8IsM29HPheX12SWkuO0eoub4G 0yEOOO5DwhPUzfPtmsz5m4cWLOzJmFuhod/YTiM4PdRhcYE1SbcJVj8HXg49dQ== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1767493686; a=rsa-sha256; cv=none; b=LELajCu0NHORuFwxyq3ExjjO8PJ/mVggCzBUV4TSirCzfqjAAyVUWfd2C2QFZWxDaGmYxN 7480O2Afji5cSs7l4sb6tlnqVuYaU+PATt0bTCMB0/MTpbKux/O8nJFo4410sxG47CaXMB wmh2d2QPGMcao4+BvWktA2NU4qN6Aq6h6ychJDTUJpqMitEdU6WLwcYyuF5TudHUOgA3j2 NkSE7UzYZZeObePX9y1g4o9kcPXoIJegl+YH6qY/l6MKfEc9VaoxBG1I5jOGTSHsjOw63/ 3WzhuQLlowYEmKl2gOZ2zJb1uUffrSbZ/Hy5F7g9GsWli14GgIrhbZ9u/uUnlQ== 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 4dkLvB2LQczW2 for ; Sun, 04 Jan 2026 02:28:06 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id a488 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Sun, 04 Jan 2026 02:28:06 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Adrian Chadd Subject: git: 8df2e5421468 - main - powerpc: put the isync inside the TD_LOCK() checking loop List-Id: Commit messages for the main branch of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-main List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-main@freebsd.org Sender: owner-dev-commits-src-main@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/main X-Git-Reftype: branch X-Git-Commit: 8df2e542146801fd01675e56724eaa567d04c209 Auto-Submitted: auto-generated Date: Sun, 04 Jan 2026 02:28:06 +0000 Message-Id: <6959d036.a488.771ea5c1@gitrepo.freebsd.org> The branch main has been updated by adrian: URL: https://cgit.FreeBSD.org/src/commit/?id=8df2e542146801fd01675e56724eaa567d04c209 commit 8df2e542146801fd01675e56724eaa567d04c209 Author: Adrian Chadd AuthorDate: 2026-01-03 22:52:14 +0000 Commit: Adrian Chadd CommitDate: 2026-01-04 02:27:48 +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 --- 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 */