y1CtNR04DOBZgdqBTLl5SFRVElIinByRIi7WpSscic6/qNFcN ayqxYzIidzkqU5JQk5t4Lk0d+Bf3wuNx2P191a+jCII4tl8B00ij7W8C/NVPM1LtWdkjRs 6MASvaTnmMPFhHU0y4EKqHd04FbITbLwZsIsUcBp+IiQRSwca+OHMzqXbh2Jnw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1760494367; a=rsa-sha256; cv=none; b=T8lAxbEPfF6xng8VkQuIQt0GYj6pLyNQaqGXt/5t+ahDdQNlPv8hGES3jZl7ZEet967OCX urkejEybgKiwcf9KGP7hP7Njc7I4a93gDZGCKmP8ozZFOLU8P9CjcXYzV5MaOa7+uR0F6/ +OPRjflVg7mnL59pSqljY1XC3eRXWRKk3tMU46xvMNOIwLGg4nmRoDainlq2OadeIGiIlj DGnfxPKFrOHMDx7Lj0aT57Z4IMhf3Npf2nfb3ZGcQW9Z4gLOmcuiXpHNaZW0t7kj/WysCq ieI57jcEvI7njK5HM0pwWgu+TAWsfVxoI8VJpTAvIYn4yZ4Kb2sXefNDRol6VA== ARC-Authentication-Results: i=1; mx1.freebsd.org; none Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (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 did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 4cmZNt6GDzz3GS; Wed, 15 Oct 2025 02:12:46 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.18.1/8.18.1) with ESMTP id 59F2Ckcx085988; Wed, 15 Oct 2025 02:12:46 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 59F2Cko1085985; Wed, 15 Oct 2025 02:12:46 GMT (envelope-from git) Date: Wed, 15 Oct 2025 02:12:46 GMT Message-Id: <202510150212.59F2Cko1085985@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mateusz Guzik Subject: git: 57bf745be964 - stable/14 - vfs offset: fix assertion failure in face of racing ffofset and setfl locking List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: mjg X-Git-Repository: src X-Git-Refname: refs/heads/stable/14 X-Git-Reftype: branch X-Git-Commit: 57bf745be96462355350fa18ec1dadfa9f04a10d Auto-Submitted: auto-generated The branch stable/14 has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=57bf745be96462355350fa18ec1dadfa9f04a10d commit 57bf745be96462355350fa18ec1dadfa9f04a10d Author: Mateusz Guzik AuthorDate: 2025-10-05 17:03:54 +0000 Commit: Mateusz Guzik CommitDate: 2025-10-15 02:12:32 +0000 vfs offset: fix assertion failure in face of racing ffofset and setfl locking Both use the same 16 bit var to store their locked and waiters bits, then this in file_v_unlock: state = atomic_load_16(flagsp); if ((state & lock_wait_bit) == 0 && atomic_cmpset_rel_16(flagsp, state, state & ~lock_bit)) return; can fail if for example foffset is being unlocked while setfl is getting locked. Afterwards the code assumes there are blocked waiters on foffset. Reviewed by: kib, markj Sponsored by: Rubicon Communications, LLC ("Netgate") Differential Revision: https://reviews.freebsd.org/D52915 --- sys/kern/vfs_vnops.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c index 5b25e2680ee4..4d1df41cf588 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -767,9 +767,12 @@ file_v_lock(struct file *fp, short lock_bit, short lock_wait_bit) flagsp = &fp->f_vflags; state = atomic_load_16(flagsp); - if ((state & lock_bit) == 0 && - atomic_cmpset_acq_16(flagsp, state, state | lock_bit)) - return; + for (;;) { + if ((state & lock_bit) != 0) + break; + if (atomic_fcmpset_acq_16(flagsp, &state, state | lock_bit)) + return; + } sleepq_lock(flagsp); state = atomic_load_16(flagsp); @@ -803,9 +806,12 @@ file_v_unlock(struct file *fp, short lock_bit, short lock_wait_bit) flagsp = &fp->f_vflags; state = atomic_load_16(flagsp); - if ((state & lock_wait_bit) == 0 && - atomic_cmpset_rel_16(flagsp, state, state & ~lock_bit)) - return; + for (;;) { + if ((state & lock_wait_bit) != 0) + break; + if (atomic_fcmpset_rel_16(flagsp, &state, state & ~lock_bit)) + return; + } sleepq_lock(flagsp); MPASS((*flagsp & lock_bit) != 0);