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Biederman) To: Alexey Gladkov Cc: syzbot , adobriyan@gmail.com, keescook@chromium.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk References: <20200610130422.1197386-1-gladkov.alexey@gmail.com> <20200610183549.1234214-1-gladkov.alexey@gmail.com> Date: Wed, 10 Jun 2020 15:17:22 -0500 In-Reply-To: <20200610183549.1234214-1-gladkov.alexey@gmail.com> (Alexey Gladkov's message of "Wed, 10 Jun 2020 20:35:49 +0200") Message-ID: <87eeqmzne5.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jj7E2-00080u-Ef;;;mid=<87eeqmzne5.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18c/i2m4LzZvVR3NXfr4aSXpqcWLF2oyW0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa08.xmission.com X-Spam-Level: X-Spam-Status: No, score=0.5 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TM2_M_HEADER_IN_MSG,XMSubLong autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4889] * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa08 0; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: ; sa08 0; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Alexey Gladkov X-Spam-Relay-Country: X-Spam-Timing: total 243 ms - load_scoreonly_sql: 0.04 (0.0%), signal_user_changed: 12 (5.1%), b_tie_ro: 11 (4.4%), parse: 0.83 (0.3%), extract_message_metadata: 10 (4.0%), get_uri_detail_list: 0.77 (0.3%), tests_pri_-1000: 13 (5.3%), tests_pri_-950: 1.34 (0.6%), tests_pri_-900: 1.25 (0.5%), tests_pri_-90: 74 (30.3%), check_bayes: 72 (29.4%), b_tokenize: 4.2 (1.7%), b_tok_get_all: 6 (2.4%), b_comp_prob: 1.67 (0.7%), b_tok_touch_all: 55 (22.8%), b_finish: 1.33 (0.5%), tests_pri_0: 118 (48.8%), check_dkim_signature: 0.43 (0.2%), check_dkim_adsp: 2.6 (1.1%), poll_dns_idle: 1.04 (0.4%), tests_pri_10: 2.0 (0.8%), tests_pri_500: 7 (2.9%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH v2] proc: s_fs_info may be NULL when proc_kill_sb is called X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Alexey Gladkov writes: > syzbot found that proc_fill_super() fails before filling up sb->s_fs_info, > deactivate_locked_super() will be called and sb->s_fs_info will be NULL. > The proc_kill_sb() does not expect fs_info to be NULL which is wrong. > > Link: https://lore.kernel.org/lkml/0000000000002d7ca605a7b8b1c5@google.com > Reported-by: syzbot+4abac52934a48af5ff19@syzkaller.appspotmail.com > Fixes: fa10fed30f25 ("proc: allow to mount many instances of proc in one pid namespace") > Signed-off-by: Alexey Gladkov applied Eric