From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx48omXKV+lBcShnMibuFqRgNtcemoO7VG1VRAZOgnp2ONRocXOUuDQ2lZXRWOTG9Jc2lWNr0 ARC-Seal: i=1; a=rsa-sha256; t=1524406465; cv=none; d=google.com; s=arc-20160816; b=1LoWRDhx4c1mIfK3hhnRqblAaaHmi3t7I05kXJsrRfiNg39tWRE55S03162Bfdbna0 kyGGSmpALTjO8vofZFVGBmzZowmD/bwIu6rRogLQDolOuDW9g4hqGyF0lAFSRpf/+boA HrFln4yKaeaF6NjCnsed3foBbTvjRKoxVLXhj1kyshMGVZhkuPgx7IZA9P2zt3Dt+n0P j3WpdHaWQ0wOvPA9Fdv9bqF7gGyVgif4GfvzyIlgxMpahJRSMTt/qcioasVWAO350Qgo yHKnfbZvFAHW79+gyZMm1oM0I2py67YLZEczpqKADP963KiujWhnL2kjzxnQG1RRcJcS vZtQ== 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=on2oWJfh21TiS7RFPkvqLGctsQvjwfPp0qYd/sGsGAI=; b=E35XFAvzDSyD4S+Xwm/m9ny6veDAOuHwov3oWoeXXZVFSb40cwXCnGsSjwo9YWfkXG /yfi9kB4Ea/L9zF6PMPqT0jhvtVZMwuok4DHFRHJTHmcNsgjzZatZPXpLfbA1eTK97bV ihNhFSngcHZYoZioXU3UJ9PkbTFjEpAzCWY9zZwFCHgWoY7hQuaWnHq+jd8hkb5bDXxj DPCN9MnnM37PoIflit6yUhiTLZRbQqEXbfoXfJyL83Q+/iX0Xd5LeOk4RxAFGVKhlWPE mkATBSUhNWVR+ZefxRdp0wgJOKziei0ECYOLZIoHBfJbmijx/3AVt9kKvpmrq1DW9/tE sQyg== 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, James Hogan , Matt Redfearn , Ralf Baechle , linux-mips@linux-mips.org Subject: [PATCH 4.9 81/95] MIPS: memset.S: Fix return of __clear_user from Lpartial_fixup Date: Sun, 22 Apr 2018 15:53:50 +0200 Message-Id: <20180422135213.740637068@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180422135210.432103639@linuxfoundation.org> References: <20180422135210.432103639@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?1598455264978774304?= X-GMAIL-MSGID: =?utf-8?q?1598456033921140798?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matt Redfearn commit daf70d89f80c6e1772233da9e020114b1254e7e0 upstream. The __clear_user function is defined to return the number of bytes that could not be cleared. From the underlying memset / bzero implementation this means setting register a2 to that number on return. Currently if a page fault is triggered within the memset_partial block, the value loaded into a2 on return is meaningless. The label .Lpartial_fixup\@ is jumped to on page fault. In order to work out how many bytes failed to copy, the exception handler should find how many bytes left in the partial block (andi a2, STORMASK), add that to the partial block end address (a2), and subtract the faulting address to get the remainder. Currently it incorrectly subtracts the partial block start address (t1), which has additionally been clobbered to generate a jump target in memset_partial. Fix this by adding the block end address instead. This issue was found with the following test code: int j, k; for (j = 0; j < 512; j++) { if ((k = clear_user(NULL, j)) != j) { pr_err("clear_user (NULL %d) returned %d\n", j, k); } } Which now passes on Creator Ci40 (MIPS32) and Cavium Octeon II (MIPS64). Suggested-by: James Hogan Signed-off-by: Matt Redfearn Cc: Ralf Baechle Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/19108/ Signed-off-by: James Hogan Signed-off-by: Greg Kroah-Hartman --- arch/mips/lib/memset.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/lib/memset.S +++ b/arch/mips/lib/memset.S @@ -251,7 +251,7 @@ PTR_L t0, TI_TASK($28) andi a2, STORMASK LONG_L t0, THREAD_BUADDR(t0) - LONG_ADDU a2, t1 + LONG_ADDU a2, a0 jr ra LONG_SUBU a2, t0