From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 2C6293858C5F; Tue, 21 Mar 2023 19:14:45 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 2C6293858C5F DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1679426085; bh=xySdZ7AI1cqKMLvS+ULqyviw5W9pNyFVOvpIN7c55A0=; h=From:To:Subject:Date:From; b=Pu9bYm1B29G5dILzX71/A8cqmXYei9COcXQp1ZOCAW2+ALB+SCPu09VME8wH6+EiL gM7CdzAdge3XtO0sclQ8ZK9vFoxQzFH+IXdLLsejcxQ+KNADsg4je7SdqUpF09YFrv WekiJLpi6xl+g2+NcfzyoAol2+6yvUqQy/VYFOrc= From: "dmalcolm at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug analyzer/109239] New: -Wanalyzer-deref-before-check seen on Linux kernel due to inlining with -fno-delete-null-pointer-checks Date: Tue, 21 Mar 2023 19:14:44 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: analyzer X-Bugzilla-Version: 13.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: dmalcolm at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: dmalcolm at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter target_milestone attachments.created Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D109239 Bug ID: 109239 Summary: -Wanalyzer-deref-before-check seen on Linux kernel due to inlining with -fno-delete-null-pointer-checks Product: gcc Version: 13.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: analyzer Assignee: dmalcolm at gcc dot gnu.org Reporter: dmalcolm at gcc dot gnu.org Target Milestone: --- Created attachment 54724 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=3D54724&action=3Dedit Reproducer I'm seeing various -Wanalyzer-deref-before-check false positives on the Lin= ux kernel; hopefully the attached is a representative reproducer for all of th= em. When compiled with: -fanalyzer -fno-delete-null-pointer-checks -O2 trunk falsely complains: In function 'bus_get', inlined from 'bus_remove_file' at :122:7, inlined from 'remove_probe_files' at :139:3, inlined from 'bus_unregister' at :150:3: :105:6: warning: check of 'bus' for NULL after already dereferencin= g it [-Wanalyzer-deref-before-check] 105 | if (bus) { | ^ 'bus_unregister': events 1-2 | | 147 | if (bus->dev_root) | | ~~~^~~~~~~~~~ | | | | | (1) pointer 'bus' is dereferenced here |...... | 150 | remove_probe_files(bus); | | ~=20=20=20=20=20=20=20 | | | | | (2) inlined call to 'remove_probe_files' from 'bus_unregiste= r' | +--> 'remove_probe_files': event 3 | | 139 | bus_remove_file(bus, &bus_attr_drivers_autoprobe); | | ^ | | | | | (3) inlined call to 'bus_remove_file' from 'remove_probe_files' | +--> 'bus_remove_file': event 4 | | 122 | if (bus_get(bus)) { | | ^ | | | | | (4) inlined call to 'bus_get' from 'bus_remove_file' | +--> 'bus_get': event 5 | | 105 | if (bus) { | | ^ | | | | | (5) pointer 'bus' is checked for NULL here but it was already dereferenced at (1) | Compiler returned: 0 Trunk: https://godbolt.org/z/ErKf6fz86=