From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48zlb/bSjpa5d58R3DbgJ0OkZpc4pSK44k1dDqocg1VyFSzzafxCz3fMTDVgtQO62t4bwwo ARC-Seal: i=1; a=rsa-sha256; t=1522168205; cv=none; d=google.com; s=arc-20160816; b=MGDMiJ9cspvIlud1WK+eAECNZXRLTuHNck6qWHUQU5Bqd39GRgWaJgDbquyiOJhojC CNeJXuM+xlbmXhoRHezrGbn6vDOZvDWrssOoJaW+Ek+8cbqLcYtY4q/To1WJHwHB6Hmp vseKcnAV+rOk1pj11spJ5CsE/mfxEjXZFeZANx3cqNDDUFkzMis9yJQTRGdB4w5PRJkx nAvzfhOk8RZNvQCaZ049cYG7LLf8ntcWOf2T/N1GQigtQvIsLBQRBTXCenO7P7XWcnfz gWIx4G5LIc76jXum5M9agMHqmPlQGeA9ZQ0yC4ihPWHeykIOODay9KmRQuy3eYEqMOvH PQ9g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=f3HvRodcle/4p6ugWV8k/x/PWziHxgRobXOz24bPIh4=; b=Mvjq05yS1ImJddXafMo9q8FtyWamGKP6arXoO94+J5ylOCih4ctvI7c9W5x3WqjXdt 1YEDwQwuz18v0GoDPqhUcKmUVuAHz6QN0rdFqN9upd2dt+d6iBlEHkZWX0/SfnZOkSHz 4rpb0Owf8c3SVDnZLzOBFBe0TRPrwQYiwuN3g/4dxsaD4Q8bGvl47FPeSP6KmVP5NPLg UrFkYBYPMjhqG+rw2ZkGrod95KG6IwPU/jFiLG89BwpFa1rfmti+3gJIvF5qtSN5WgOd ydTsieyPGzmURKg2j0RZb7Yu3sGMzgQfFSwiQo2TBOUTe3tBJ9QBZGySJRK+ZZfyCrpj G1Kg== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+f7b556d1766502a69d85071d2ff08bd87be53d0f@syzkaller.appspotmail.com, Eric Biggers , Tejun Heo Subject: [PATCH 4.4 13/43] libata: remove WARN() for DMA or PIO command without data Date: Tue, 27 Mar 2018 18:27:17 +0200 Message-Id: <20180327162717.131571418@linuxfoundation.org> X-Mailer: git-send-email 2.16.3 In-Reply-To: <20180327162716.407986916@linuxfoundation.org> References: <20180327162716.407986916@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1596109047910699948?= X-GMAIL-MSGID: =?utf-8?q?1596109047910699948?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 9173e5e80729c8434b8d27531527c5245f4a5594 upstream. syzkaller hit a WARN() in ata_qc_issue() when writing to /dev/sg0. This happened because it issued a READ_6 command with no data buffer. Just remove the WARN(), as it doesn't appear indicate a kernel bug. The expected behavior is to fail the command, which the code does. Here's a reproducer that works in QEMU when /dev/sg0 refers to a disk of the default type ("82371SB PIIX3 IDE"): #include #include int main() { char buf[42] = { [36] = 0x8 /* READ_6 */ }; write(open("/dev/sg0", O_RDWR), buf, sizeof(buf)); } Fixes: f92a26365a72 ("libata: change ATA_QCFLAG_DMAMAP semantics") Reported-by: syzbot+f7b556d1766502a69d85071d2ff08bd87be53d0f@syzkaller.appspotmail.com Cc: # v2.6.25+ Signed-off-by: Eric Biggers Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman --- drivers/ata/libata-core.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/drivers/ata/libata-core.c +++ b/drivers/ata/libata-core.c @@ -5077,8 +5077,7 @@ void ata_qc_issue(struct ata_queued_cmd * We guarantee to LLDs that they will have at least one * non-zero sg if the command is a data command. */ - if (WARN_ON_ONCE(ata_is_data(prot) && - (!qc->sg || !qc->n_elem || !qc->nbytes))) + if (ata_is_data(prot) && (!qc->sg || !qc->n_elem || !qc->nbytes)) goto sys_err; if (ata_is_dma(prot) || (ata_is_pio(prot) &&