From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 13A9D28F7; Thu, 27 Jun 2024 01:00:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719450023; cv=none; b=aIXwuzrM3J9Hhm8AmERns2Gd1370cs1kEJcMk/hF92C/yt3dd/QyrlMLQVwMtFm4PVDRYu904awr/Z5ARlnndgqy8Ckl93daYv7TuXKpZdTzSW4PCT0/57vOHEeyo/bSEHEnNcbnrLB3yRuTtzvkmJvdM8L0lQMJOSaSCDSTi4Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719450023; c=relaxed/simple; bh=ibtuksqqHRbw6xYn2I+QgP7GZTfnwLjkGVNyxPhsDBE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=E5WdX/nq12P8DoYlSY7hHDaAhv4Ye2ETE+RqnjmZalJ9Y/yvbn7Lr41biQ5i2KioqEL6u6ga99Rig2wXshSBVpiGbKyNvblQ86A+G7oYvmOMZ+L95oZiNjCBVj4wf5Czs7ahGQvOqCynFP3GdXEADmeccxFg4KHtpbGg1ckN780= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=XquNmEqR; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="XquNmEqR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 584C0C116B1; Thu, 27 Jun 2024 01:00:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719450022; bh=ibtuksqqHRbw6xYn2I+QgP7GZTfnwLjkGVNyxPhsDBE=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=XquNmEqRetw+AivJGWZ0WN6xjRna28dOyjIIa+8OCOwxiyMQ7Ul3IAnsU9wE5Vu60 hA/8fkTmZi3sSf7QOJ6hPEcl6ZT0SfEjqlb2sOr1M77LRJGaUEWb8re3pBoju+crd0 YCcnP4MIOgWVK8Yam/r6yLwXzLU4AkzWxjPTb7T5Zm6vH9iGnF0IFpFcGfjPeJj1ul 2JJnWPIc4tAFrHwkHEcPBxsa3eB3ZMkWEyxpNN1k3+EtBFDpShHMn0gAYx5ws2Loa5 UXWcMLHCs6xRGcxqau16AHNWE6zBTGVSddlvev/XKQTaqJgPaTchwD5wTK3bHjWAli QODR63Rlolw+Q== Message-ID: <650615d5-031e-4a60-a452-3e541dc5f771@kernel.org> Date: Thu, 27 Jun 2024 10:00:20 +0900 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 01/13] ata: libata-core: Fix null pointer dereference on error To: Niklas Cassel , Tejun Heo , Jeff Garzik Cc: linux-scsi@vger.kernel.org, John Garry , Jason Yan , "Martin K. Petersen" , "James E.J. Bottomley" , stable@vger.kernel.org, linux-ide@vger.kernel.org References: <20240626180031.4050226-15-cassel@kernel.org> <20240626180031.4050226-16-cassel@kernel.org> From: Damien Le Moal Content-Language: en-US Organization: Western Digital Research In-Reply-To: <20240626180031.4050226-16-cassel@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/27/24 03:00, Niklas Cassel wrote: > If the ata_port_alloc() call in ata_host_alloc() fails, > ata_host_release() will get called. > > However, the code in ata_host_release() tries to free ata_port struct > members unconditionally, which can lead to the following: > > BUG: unable to handle page fault for address: 0000000000003990 > PGD 0 P4D 0 > Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI > CPU: 10 PID: 594 Comm: (udev-worker) Not tainted 6.10.0-rc5 #44 > Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014 > RIP: 0010:ata_host_release.cold+0x2f/0x6e [libata] > Code: e4 4d 63 f4 44 89 e2 48 c7 c6 90 ad 32 c0 48 c7 c7 d0 70 33 c0 49 83 c6 0e 41 > RSP: 0018:ffffc90000ebb968 EFLAGS: 00010246 > RAX: 0000000000000041 RBX: ffff88810fb52e78 RCX: 0000000000000000 > RDX: 0000000000000000 RSI: ffff88813b3218c0 RDI: ffff88813b3218c0 > RBP: ffff88810fb52e40 R08: 0000000000000000 R09: 6c65725f74736f68 > R10: ffffc90000ebb738 R11: 73692033203a746e R12: 0000000000000004 > R13: 0000000000000000 R14: 0000000000000011 R15: 0000000000000006 > FS: 00007f6cc55b9980(0000) GS:ffff88813b300000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000003990 CR3: 00000001122a2000 CR4: 0000000000750ef0 > PKRU: 55555554 > Call Trace: > > ? __die_body.cold+0x19/0x27 > ? page_fault_oops+0x15a/0x2f0 > ? exc_page_fault+0x7e/0x180 > ? asm_exc_page_fault+0x26/0x30 > ? ata_host_release.cold+0x2f/0x6e [libata] > ? ata_host_release.cold+0x2f/0x6e [libata] > release_nodes+0x35/0xb0 > devres_release_group+0x113/0x140 > ata_host_alloc+0xed/0x120 [libata] > ata_host_alloc_pinfo+0x14/0xa0 [libata] > ahci_init_one+0x6c9/0xd20 [ahci] > > Do not access ata_port struct members unconditionally. > > Fixes: 633273a3ed1c ("libata-pmp: hook PMP support and enable it") > Cc: stable@vger.kernel.org > Signed-off-by: Niklas Cassel Looks good, with a nit below. This should be queued as soon as possible as a 6.10 fix patch. Reviewed-by: Damien Le Moal > --- > drivers/ata/libata-core.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c > index e1bf8a19b3c8..88e32f638f33 100644 > --- a/drivers/ata/libata-core.c > +++ b/drivers/ata/libata-core.c > @@ -5518,10 +5518,12 @@ static void ata_host_release(struct kref *kref) > for (i = 0; i < host->n_ports; i++) { > struct ata_port *ap = host->ports[i]; > > - kfree(ap->pmp_link); > - kfree(ap->slave_link); > - kfree(ap->ncq_sense_buf); > - kfree(ap); > + if (ap) { > + kfree(ap->pmp_link); > + kfree(ap->slave_link); > + kfree(ap->ncq_sense_buf); > + kfree(ap); > + } > host->ports[i] = NULL; Nit: this line can go inside the if as well. Or even better: reverse the if condition and continue to ignore NULL ports. for (i = 0; i < host->n_ports; i++) { struct ata_port *ap = host->ports[i]; if (!ap) continue; kfree(ap->pmp_link); kfree(ap->slave_link); kfree(ap->ncq_sense_buf); kfree(ap); host->ports[i] = NULL; } -- Damien Le Moal Western Digital Research