From owner-svn-src-all@freebsd.org Sat Nov 7 13:09:51 2020 Return-Path: Delivered-To: svn-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id B879B2EF3DC; Sat, 7 Nov 2020 13:09:51 +0000 (UTC) (envelope-from trasz@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 "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4CSyKC4tY7z4n3G; Sat, 7 Nov 2020 13:09:51 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org (repo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 9ACE37189; Sat, 7 Nov 2020 13:09:51 +0000 (UTC) (envelope-from trasz@FreeBSD.org) Received: from repo.freebsd.org ([127.0.1.37]) by repo.freebsd.org (8.15.2/8.15.2) with ESMTP id 0A7D9pbe046518; Sat, 7 Nov 2020 13:09:51 GMT (envelope-from trasz@FreeBSD.org) Received: (from trasz@localhost) by repo.freebsd.org (8.15.2/8.15.2/Submit) id 0A7D9pcm046517; Sat, 7 Nov 2020 13:09:51 GMT (envelope-from trasz@FreeBSD.org) Message-Id: <202011071309.0A7D9pcm046517@repo.freebsd.org> X-Authentication-Warning: repo.freebsd.org: trasz set sender to trasz@FreeBSD.org using -f From: Edward Tomasz Napierala Date: Sat, 7 Nov 2020 13:09:51 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r367445 - head/sys/kern X-SVN-Group: head X-SVN-Commit-Author: trasz X-SVN-Commit-Paths: head/sys/kern X-SVN-Commit-Revision: 367445 X-SVN-Commit-Repository: base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 07 Nov 2020 13:09:51 -0000 Author: trasz Date: Sat Nov 7 13:09:51 2020 New Revision: 367445 URL: https://svnweb.freebsd.org/changeset/base/367445 Log: Move TDB_USERWR check under 'if (traced)'. If we hadn't been traced in the first place when syscallenter() started executing, we can ignore TDB_USERWR. TDB_USERWR can get set, sure, but if it does, it's because the debugger raced with the syscall, and it cannot depend on winning that race. Reviewed by: kib MFC after: 2 weeks Sponsored by: EPSRC Differential Revision: https://reviews.freebsd.org/D26585 Modified: head/sys/kern/subr_syscall.c Modified: head/sys/kern/subr_syscall.c ============================================================================== --- head/sys/kern/subr_syscall.c Sat Nov 7 05:10:46 2020 (r367444) +++ head/sys/kern/subr_syscall.c Sat Nov 7 13:09:51 2020 (r367445) @@ -97,21 +97,22 @@ syscallenter(struct thread *td) if (p->p_ptevents & PTRACE_SCE) ptracestop((td), SIGTRAP, NULL); PROC_UNLOCK(p); - } - if (__predict_false((td->td_dbgflags & TDB_USERWR) != 0)) { - /* - * Reread syscall number and arguments if debugger - * modified registers or memory. - */ - error = (p->p_sysent->sv_fetch_syscall_args)(td); - se = sa->callp; + + if ((td->td_dbgflags & TDB_USERWR) != 0) { + /* + * Reread syscall number and arguments if debugger + * modified registers or memory. + */ + error = (p->p_sysent->sv_fetch_syscall_args)(td); + se = sa->callp; #ifdef KTRACE - if (KTRPOINT(td, KTR_SYSCALL)) - ktrsyscall(sa->code, se->sy_narg, sa->args); + if (KTRPOINT(td, KTR_SYSCALL)) + ktrsyscall(sa->code, se->sy_narg, sa->args); #endif - if (error != 0) { - td->td_errno = error; - goto retval; + if (error != 0) { + td->td_errno = error; + goto retval; + } } }