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[2003:cf:d723:2e31:9b54:c0c7:20fe:e73c]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4313f56eab2sm23250825e9.26.2024.10.15.10.04.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 15 Oct 2024 10:04:42 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729011887; 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: content-transfer-encoding:content-transfer-encoding; bh=Jrb/0uMLqZHYTAHN4atajS/ryKUEyxy2luVY5BUsLJM=; b=H+pXJoSwKAE/EbQjrPDLIQ3HDZ6vmHKW2Zzl2GFa8xcBKUNKt8pkpNWoSzFoLFRonsCaP6 mYrGZ8mzTFfhp4lgzVceXz4Vz2d9TbXjoX0ee5GwCs6W4FXEOg7swBQhuafbdiPxc2JbEa B6t31g96SqxPgMq8v6swqohN9T84+Wg= X-MC-Unique: VqodJGCIO52msR6t51_NEg-1 X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729011885; x=1729616685; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Jrb/0uMLqZHYTAHN4atajS/ryKUEyxy2luVY5BUsLJM=; b=GYAfkFxTw7JNb1oi+MOMWQAgiIu6pgdqdaQUfD0juYfZYaUpNeljXRVHzeqliaRP/F MblQ8d4wlnX06j+WnADCofoR9arwLff9j8CLjU9KkETpMgpr5y+Vf8jDhYEM32DGhL3K P9uTcSa82qt5Ot1IbkNO4mthdN8Xw/vFJikSV57NSO9yTFHo0baulAyf2sDAdyXwWnCD lKeTHLeTOma1Gu4TCVipS17KE3lVE4pCTfnv17WDn38gupDeIWJKFuHTkgEfg6Xq3Uni tCIq+36p+/uFmZ1zTnW71Qmu11RShYpgMHto4T9XEgG0tTx+5u1OMCarDkSZpX+mBJyw SFTQ== X-Gm-Message-State: AOJu0Yw7NQaKoIb605n3KULIxon5ruMsUVchBb9Bb6YmqB0iQk/1WdLs 06B6SJpW1yaIwFyIBkuxVgaROvne5x0DpAfLyfQcaPi1OgKK0zc55Y4baf8NpcSr5dzaa2SC6Wy eHG8X57nlE96lG1Ex8rlU74OzrMz+d0evwDohlEA8xjE9CFuD00O8JeyMdjpjkg4P6kaIqDTNid ETg4V0Y1NtfCfKOLWePZAj76MkJcbIQtVDVQ== X-Received: by 2002:a05:600c:a0f:b0:42c:ac9f:b528 with SMTP id 5b1f17b1804b1-4311df5c600mr124540615e9.35.1729011884601; Tue, 15 Oct 2024 10:04:44 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEHkMDNycAq4NmFnEjeuBGP2H5vlIYRAjHYhpXoY55UpBwB7/exCRvhSWWvhi8NfARkag16nQ== X-Received: by 2002:a05:600c:a0f:b0:42c:ac9f:b528 with SMTP id 5b1f17b1804b1-4311df5c600mr124540215e9.35.1729011884116; Tue, 15 Oct 2024 10:04:44 -0700 (PDT) From: Hanna Czenczek To: qemu-devel@nongnu.org Cc: Hanna Czenczek , Peter Xu , Fabiano Rosas , qemu-stable@nongnu.org Subject: [PATCH v2] migration: Ensure vmstate_save() sets errp Date: Tue, 15 Oct 2024 19:04:37 +0200 Message-ID: <20241015170437.310358-1-hreitz@redhat.com> X-Mailer: git-send-email 2.45.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=hreitz@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.063, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1729011919550116600 Content-Type: text/plain; charset="utf-8" migration/savevm.c contains some calls to vmstate_save() that are followed by migrate_set_error() if the integer return value indicates an error. migrate_set_error() requires that the `Error *` object passed to it is set. Therefore, vmstate_save() is assumed to always set *errp on error. Right now, that assumption is not met: vmstate_save_state_v() (called internally by vmstate_save()) will not set *errp if vmstate_subsection_save() or vmsd->post_save() fail. Fix that by adding an *errp parameter to vmstate_subsection_save(), and by generating a generic error in case post_save() fails (as is already done for pre_save()). Without this patch, qemu will crash after vmstate_subsection_save() or post_save() have failed inside of a vmstate_save() call (unless migrate_set_error() then happen to discard the new error because s->error is already set). This happens e.g. when receiving the state from a virtio-fs back-end (virtiofsd) fails. Signed-off-by: Hanna Czenczek --- v2: As suggested by Peter, after vmsd->post_save(), change the condition from `if (!ret)` to `if (!ret && ps_ret)` so we will not create an error object in case of success (that would then be leaked, most likely). --- migration/vmstate.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/migration/vmstate.c b/migration/vmstate.c index ff5d589a6d..fa002b24e8 100644 --- a/migration/vmstate.c +++ b/migration/vmstate.c @@ -22,7 +22,8 @@ #include "trace.h" =20 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *= vmsd, - void *opaque, JSONWriter *vmdesc); + void *opaque, JSONWriter *vmdesc, + Error **errp); static int vmstate_subsection_load(QEMUFile *f, const VMStateDescription *= vmsd, void *opaque); =20 @@ -441,12 +442,13 @@ int vmstate_save_state_v(QEMUFile *f, const VMStateDe= scription *vmsd, json_writer_end_array(vmdesc); } =20 - ret =3D vmstate_subsection_save(f, vmsd, opaque, vmdesc); + ret =3D vmstate_subsection_save(f, vmsd, opaque, vmdesc, errp); =20 if (vmsd->post_save) { int ps_ret =3D vmsd->post_save(opaque); - if (!ret) { + if (!ret && ps_ret) { ret =3D ps_ret; + error_setg(errp, "post-save failed: %s", vmsd->name); } } return ret; @@ -518,7 +520,8 @@ static int vmstate_subsection_load(QEMUFile *f, const V= MStateDescription *vmsd, } =20 static int vmstate_subsection_save(QEMUFile *f, const VMStateDescription *= vmsd, - void *opaque, JSONWriter *vmdesc) + void *opaque, JSONWriter *vmdesc, + Error **errp) { const VMStateDescription * const *sub =3D vmsd->subsections; bool vmdesc_has_subsections =3D false; @@ -546,7 +549,7 @@ static int vmstate_subsection_save(QEMUFile *f, const V= MStateDescription *vmsd, qemu_put_byte(f, len); qemu_put_buffer(f, (uint8_t *)vmsdsub->name, len); qemu_put_be32(f, vmsdsub->version_id); - ret =3D vmstate_save_state(f, vmsdsub, opaque, vmdesc); + ret =3D vmstate_save_state_with_err(f, vmsdsub, opaque, vmdesc= , errp); if (ret) { return ret; } --=20 2.45.2