From nobody Sun Oct 05 21:22:01 2025 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 4cfwMZ1mNjz6BjXJ; Sun, 05 Oct 2025 21:22:02 +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 "R12" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4cfwMY68yLz474n; Sun, 05 Oct 2025 21:22:01 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1759699321; 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=EDEErL94dXR15uW2EfjgpxcGnE3PySZD6vWJbIy/i1A=; b=csGPukvwEkyO8ZQT8zR8TyETLD3ogkO0CwazSnCm8rdrNmNlNRHCV2ifpNDkNKIFZz0wpz clobm/3ib0F/X2vQpQNSDVvOOShGhr/bkSGF828agjr4zygdzA8LUwHL7MAbLr33hOedr6 em5nJnfchA3fu4Im2mLoRGL7dFX8t1DNT3wb9ZOmAQ6+evWJF8b1X30sk2UKuroTPRbDUu 0eNxfavEjXgfisXNPChc3HBsbHBgnG45vOE9icILQ+9S6Zr3k9ecWldwhbxJkxYALYZ+dW Akum61ztbydfpqvc91MxaaKCOgpC6Lldcun2gJMaRr5XbisdAF2nPkF5XO3D1Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1759699321; 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=EDEErL94dXR15uW2EfjgpxcGnE3PySZD6vWJbIy/i1A=; b=n1gwIgGifiZZVECTIZ+IkMC33UYQ70m3A7/b2ConvbP5e4YzQ9gCXoqdwVKBlI9QdmX37q falEKeuoeVRPeT120X+iYZAhHVSiJkDNsJtkeVF8JAqJWUVkbp2Fo/CGBfq5BHoojamrI7 KAaz1Y0HEWF7DQ/MYKf2S9lD3hCt56JnHM2mitGShPJF3bD7aghpDbDunK0W6VZ+rQhzAU 1l2KBBukA3wXqNYRdg7au1eqpkEwe0dQe6E9JTOMyprQnpXKO1+GAfRMwhIO1LUiQ8pmO3 vgAHAZzh7ph/9UlYlshhxOVYQyVJ4aIKr8m3c9muaedufQque7T4V/jR1eKDBw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1759699321; a=rsa-sha256; cv=none; b=fKs5Mn/RWr3K6pdGQ9Lonl0k4BIWxV6R7xada807FojcRyZI81sn4T1qXoxWtuztVHefi9 2zOkqeDnnHQhlEe/O24ndMEhmvbz2anCOVXF3b7f9qTYf/Itd6pUVp8X8Lg4Vh+n8cVw4S 4EelOJAwV7eoB9p+hlbDt6TK3GPcLCMDBYQsYjiOgGG6mCTdnTNUm6e9k02DASmN5Tq4gP gym0CZyriU/wLeQnIocrwMdnjMDVI2FZSgGRzRa2k824NwceN0y0cq6fnBs2SrlXHtGLxa vx+7Vydo1v5jrmBzCC3YP4UfcfJw55q1Oo6r1kEdVohw6otB06+Km+g1z9KM4A== 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 4cfwMY5k84zTvt; Sun, 05 Oct 2025 21:22:01 +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 595LM1V7099173; Sun, 5 Oct 2025 21:22:01 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.18.1/8.18.1/Submit) id 595LM1mb099170; Sun, 5 Oct 2025 21:22:01 GMT (envelope-from git) Date: Sun, 5 Oct 2025 21:22:01 GMT Message-Id: <202510052122.595LM1mb099170@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: Mateusz Guzik Subject: git: b1de02c415de - main - vfs offset: fix assertion failure in face of racing ffofset and setfl locking 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: mjg X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: b1de02c415de5df2d24d8021827634fc095b7a26 Auto-Submitted: auto-generated The branch main has been updated by mjg: URL: https://cgit.FreeBSD.org/src/commit/?id=b1de02c415de5df2d24d8021827634fc095b7a26 commit b1de02c415de5df2d24d8021827634fc095b7a26 Author: Mateusz Guzik AuthorDate: 2025-10-05 17:03:54 +0000 Commit: Mateusz Guzik CommitDate: 2025-10-05 21:21:34 +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 c2a669dc771a..a53df50c06bd 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -806,9 +806,12 @@ 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); @@ -842,9 +845,12 @@ 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);