From nobody Tue Jul 28 02:34:50 2026 X-Original-To: dev-commits-src-all@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 4h8KLP5fkpz6mMH7; Tue, 28 Jul 2026 02:34:53 +0000 (UTC) (envelope-from glebius@freebsd.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (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 "smtp.freebsd.org", Issuer "YR1" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4h8KLP4t3pz3pbS; Tue, 28 Jul 2026 02:34:53 +0000 (UTC) (envelope-from glebius@freebsd.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1785206093; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=78heVpV1+KEvrGeS3v9/PSlst8+ABtAHV4epDBOiR/0=; b=pzqpBMSGf80SwTGdmudEneiPw1c5hJu1C9ohN5aDOUlNGPCApLl2ncx4DmqQNFRfpjfwcK +Thj6AadBuDeqHFaSj/78FfRTed61dCixGeAOblCp97Myy+jFscXae/R9+GmmAsy/vQBp/ WFdJ55gDHQ09YCBAlVo9nGyO4PoseLtaBoNguSghqI1DfhZk+k/LLlakj4YrZhWeef2wSC ReZUdTC7f5uPem63FmwUBoPQInaBb44YWbiw3475gC5PfztSuae7HFNsmy3sWxPgeH4lIu OSwaloLZPB9ZA7Shjy3xRrvO810qdJ1rGoR4N7DdMidT9sJNQzDHburKLyR4+w== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1785206093; a=rsa-sha256; cv=none; b=fS+y/OqoAarp8SXd+dCdpwPgYTkSoM3mKyIXzghhll6u/M0C0xY3DDfYZUiPrYsU8s05s7 eGWaaYiR2dfU4CpOJZKvqqf7jC54TVpTqhGuhjpzUGgQJAp0cLwmEIb9BqnEtHBPfoaw55 2QIqn74ipQ3Fc9Q5ThE5nvEKvUdSbSK05FpJyPo/bJkqUll1RZwb13L8YOlTuLKevc2wqr b1tKcFO9YD/dK79/FT6bK3vNiyQKurpgJTxbLmJ4j1+5gF87WdUr8Xb0wjkqcAuvqpKC0E l/RIfrEctdI++N0Vv+DAEW3KZceDLKBiHmHsv/4f2Jko8oIvTg3eoUGO0bEO/g== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1785206093; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=78heVpV1+KEvrGeS3v9/PSlst8+ABtAHV4epDBOiR/0=; b=mYpo0eoZxCAicCXFyJID3X7jTQQfISGer0UCzcqQeIM8lo5hv36uApLe7nvGZgHHfkVAfq BlOBadFRcchRQ2T52cmqn1vtSDZ+YLSpyqAnaK/ty2A9cWQpNkcujwH99JdAziiD1prwki 2mCLqQjC2oIBDHQmZ5tVszKwn0c65nBrrJyDlp3x/fsKXDGw9Nsz8yf69rmMhTWTQVuw24 MBw1italAE3XpJdHhkCnLHzUONvPKYET5/PdbR2MfnwVhd+gnB+ZL1adJC4/Lw3A8u41iy OGuIsg4Qeb80RBWOrt4NoACz/UFJ2c80nJJlAbceaVYWgEditOsrzSLmOETmhg== Received: from cell.glebi.us (glebi.us [162.251.186.162]) (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) (Authenticated sender: glebius) by smtp.freebsd.org (Postfix) with ESMTPSA id 4h8KLN5V31z15Dy; Tue, 28 Jul 2026 02:34:52 +0000 (UTC) (envelope-from glebius@freebsd.org) Date: Mon, 27 Jul 2026 19:34:50 -0700 From: Gleb Smirnoff To: Mark Johnston Cc: Jonathan Looney , src-committers@freebsd.org, dev-commits-src-all@freebsd.org, dev-commits-src-main@freebsd.org Subject: Re: git: 56ac3351c61f - main - witness: fix operation without WITNESS_SKIPSPIN Message-ID: References: <6a5987fd.3e063.69a4cc59@gitrepo.freebsd.org> 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 List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Jul 17, 2026 at 09:02:36AM -0400, Mark Johnston wrote: M> On Fri, Jul 17, 2026 at 01:40:13AM +0000, Gleb Smirnoff wrote: M> > The branch main has been updated by glebius: M> > M> > URL: https://cgit.FreeBSD.org/src/commit/?id=56ac3351c61f285ee5b8c9bd4411eeaeb20efe26 M> > M> > commit 56ac3351c61f285ee5b8c9bd4411eeaeb20efe26 M> > Author: Gleb Smirnoff M> > AuthorDate: 2026-07-17 01:37:03 +0000 M> > Commit: Gleb Smirnoff M> > CommitDate: 2026-07-17 01:37:03 +0000 M> > M> > witness: fix operation without WITNESS_SKIPSPIN M> > M> > Since malloc(9) even with M_NOWAIT is forbidden when we hold a spinlock, M> > we can't print detailed lock tree as the operation tries to allocate M> > memory. M> M> I think malloc() actually can't be used at all here. It's possible to M> recurse into the vmem boundary tag allocator; syzkaller triggered the M> panic below once for me. M> M> Can we preallocate a single tracker at boot time, protected by w_mtx? I'd leave this to Jonathan's decision. My personal take is that WITNESS is a helper for developers, not a production feature. If the code gives us a hint on lock order in 99% cases and recurses deep in malloc() in 1% times it is good enough. Of course if recursion can be avioded easily, this should be done. -- Gleb Smirnoff