[PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Bjørn Mork]

The ioc->sgl[i].iov_len value is supplied by the ioctl caller, and can be
zero in some cases.  Assume that's valid and continue without error.

Fixes:

[   69.162538] ------------[ cut here ]------------
[   69.162806] kernel BUG at /build/buildd/linux-2.6.32/lib/swiotlb.c:368!
[   69.163134] invalid opcode: 0000 [#1] SMP
[   69.163570] last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map
[   69.163975] CPU 0
[   69.164227] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy pata_jmicron megaraid_sas igb dca
[   69.167419] Pid: 1206, comm: smartctl Tainted: G        W  2.6.32-25-server #45-Ubuntu X8DTN
[   69.167843] RIP: 0010:[<ffffffff812c4dc5>]  [<ffffffff812c4dc5>] map_single+0x255/0x260
[   69.168370] RSP: 0018:ffff88081c0ebc58  EFLAGS: 00010246
[   69.168655] RAX: 000000000003bffc RBX: 00000000ffffffff RCX: 0000000000000002
[   69.169000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88001dffe000
[   69.169346] RBP: ffff88081c0ebcb8 R08: 0000000000000000 R09: ffff880000030840
[   69.169691] R10: 0000000000100000 R11: 0000000000000000 R12: 0000000000000000
[   69.170036] R13: 00000000ffffffff R14: 0000000000000001 R15: 0000000000200000
[   69.170382] FS:  00007fb8de189720(0000) GS:ffff88001de00000(0000) knlGS:0000000000000000
[   69.170794] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   69.171094] CR2: 00007fb8dd59237c CR3: 000000081a790000 CR4: 00000000000006f0
[   69.171439] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   69.171784] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   69.172130] Process smartctl (pid: 1206, threadinfo ffff88081c0ea000, task ffff88081a760000)
[   69.194513] Stack:
[   69.205788]  0000000000000034 00000002817e3390 0000000000000000 ffff88081c0ebe00
[   69.217739] <0> 0000000000000000 000000000003bffc 0000000000000000 0000000000000000
[   69.241250] <0> 0000000000000000 00000000ffffffff ffff88081c5b4080 ffff88081c0ebe00
[   69.277310] Call Trace:
[   69.289278]  [<ffffffff812c52ac>] swiotlb_alloc_coherent+0xec/0x130
[   69.301118]  [<ffffffff81038b31>] x86_swiotlb_alloc_coherent+0x61/0x70
[   69.313045]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.336399]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.359346]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.370902]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.382322]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.393622]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.404696]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.415761]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.426640]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.437491] Code: fe ff ff 48 8b 3d 74 38 76 00 41 bf 00 00 20 00 e8 51 f5 d7 ff 83 e0 ff 48 05 ff 07 00 00 48 c1 e8 0b 48 89 45 c8 e9 13 fe ff ff <0f> 0b eb fe 0f 1f 80 00 00 00 00 55 48 89 e5 48 83 ec 20 4c 89
[   69.478216] RIP  [<ffffffff812c4dc5>] map_single+0x255/0x260
[   69.489668]  RSP <ffff88081c0ebc58>
[   69.500975] ---[ end trace 6a2181b634e2abc7 ]---

Reported-by: Bokhan Artem <aptem@ngs.ru>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: stable@kernel.org
---
 drivers/scsi/megaraid/megaraid_sas.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index eb29d50..72713c5 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -4359,6 +4359,11 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
 	 * For each user buffer, create a mirror buffer and copy in
 	 */
 	for (i = 0; i < ioc->sge_count; i++) {
+		if (ioc->sgl[i].iov_len == 0) {
+			kbuff_arr[i] = NULL;
+			continue;
+		}
+
 		kbuff_arr[i] = dma_alloc_coherent(&instance->pdev->dev,
 						    ioc->sgl[i].iov_len,
 						    &buf_handle, GFP_KERNEL);
-- 
1.7.2.3

[PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Bjørn Mork]

The ioc->sgl[i].iov_len value is supplied by the ioctl caller, and can be
zero in some cases.  Assume that's valid and continue without error.

Fixes (multiple individual reports of the same problem for quite a while):

http://marc.info/?l=linux-ide&m=128941801715301
http://bugs.debian.org/604627
http://www.mail-archive.com/linux-poweredge@dell.com/msg02575.html

megasas: Failed to alloc kernel SGL buffer for IOCTL

and

[   69.162538] ------------[ cut here ]------------
[   69.162806] kernel BUG at /build/buildd/linux-2.6.32/lib/swiotlb.c:368!
[   69.163134] invalid opcode: 0000 [#1] SMP
[   69.163570] last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map
[   69.163975] CPU 0
[   69.164227] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy pata_jmicron megaraid_sas igb dca
[   69.167419] Pid: 1206, comm: smartctl Tainted: G        W  2.6.32-25-server #45-Ubuntu X8DTN
[   69.167843] RIP: 0010:[<ffffffff812c4dc5>]  [<ffffffff812c4dc5>] map_single+0x255/0x260
[   69.168370] RSP: 0018:ffff88081c0ebc58  EFLAGS: 00010246
[   69.168655] RAX: 000000000003bffc RBX: 00000000ffffffff RCX: 0000000000000002
[   69.169000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88001dffe000
[   69.169346] RBP: ffff88081c0ebcb8 R08: 0000000000000000 R09: ffff880000030840
[   69.169691] R10: 0000000000100000 R11: 0000000000000000 R12: 0000000000000000
[   69.170036] R13: 00000000ffffffff R14: 0000000000000001 R15: 0000000000200000
[   69.170382] FS:  00007fb8de189720(0000) GS:ffff88001de00000(0000) knlGS:0000000000000000
[   69.170794] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   69.171094] CR2: 00007fb8dd59237c CR3: 000000081a790000 CR4: 00000000000006f0
[   69.171439] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   69.171784] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   69.172130] Process smartctl (pid: 1206, threadinfo ffff88081c0ea000, task ffff88081a760000)
[   69.194513] Stack:
[   69.205788]  0000000000000034 00000002817e3390 0000000000000000 ffff88081c0ebe00
[   69.217739] <0> 0000000000000000 000000000003bffc 0000000000000000 0000000000000000
[   69.241250] <0> 0000000000000000 00000000ffffffff ffff88081c5b4080 ffff88081c0ebe00
[   69.277310] Call Trace:
[   69.289278]  [<ffffffff812c52ac>] swiotlb_alloc_coherent+0xec/0x130
[   69.301118]  [<ffffffff81038b31>] x86_swiotlb_alloc_coherent+0x61/0x70
[   69.313045]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.336399]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.359346]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.370902]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.382322]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.393622]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.404696]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.415761]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.426640]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.437491] Code: fe ff ff 48 8b 3d 74 38 76 00 41 bf 00 00 20 00 e8 51 f5 d7 ff 83 e0 ff 48 05 ff 07 00 00 48 c1 e8 0b 48 89 45 c8 e9 13 fe ff ff <0f> 0b eb fe 0f 1f 80 00 00 00 00 55 48 89 e5 48 83 ec 20 4c 89
[   69.478216] RIP  [<ffffffff812c4dc5>] map_single+0x255/0x260
[   69.489668]  RSP <ffff88081c0ebc58>
[   69.500975] ---[ end trace 6a2181b634e2abc7 ]---

Reported-by: Bokhan Artem <aptem@ngs.ru>
Reported by: Marc-Christian Petersen <m.c.p@gmx.de>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Cc: stable@kernel.org
---
 drivers/scsi/megaraid/megaraid_sas.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas.c b/drivers/scsi/megaraid/megaraid_sas.c
index eb29d50..72713c5 100644
--- a/drivers/scsi/megaraid/megaraid_sas.c
+++ b/drivers/scsi/megaraid/megaraid_sas.c
@@ -4359,6 +4359,11 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
 	 * For each user buffer, create a mirror buffer and copy in
 	 */
 	for (i = 0; i < ioc->sge_count; i++) {
+		if (ioc->sgl[i].iov_len == 0) {
+			kbuff_arr[i] = NULL;
+			continue;
+		}
+
 		kbuff_arr[i] = dma_alloc_coherent(&instance->pdev->dev,
 						    ioc->sgl[i].iov_len,
 						    &buf_handle, GFP_KERNEL);
-- 
1.7.2.3

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Re: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Bjørn Mork]

Bjørn Mork <bjorn@mork.no> writes:

> The ioc->sgl[i].iov_len value is supplied by the ioctl caller, and can be
> zero in some cases.  Assume that's valid and continue without error.
>
> Fixes (multiple individual reports of the same problem for quite a while):
>
> http://marc.info/?l=linux-ide&m=128941801715301
> http://bugs.debian.org/604627
> http://www.mail-archive.com/linux-poweredge@dell.com/msg02575.html

ping?

I don't know how to interpret the total silence...  NAKing it is better
if you don't like the code.


Bjørn

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Re: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Bjørn Mork]

"Yang, Bo" <Bo.Yang@lsi.com> writes:

> If you are using megasas ioctl routine to develop your owner
> application, the best way you may need to contact with LSI for the
> tech support.

???

Thanks for answering, but I'm afraid I don't understand.  You don't fix
bugs in the driver because you don't support the application used to
trigger it?

The application in question is smartctl which is part of
http://smartmontools.sourceforge.net and AFAIK included with most (all?)
Linux distributions.  The action required to trigger the driver bug is
attempting to initiate a SMART device self test.


Quoting from the Debian bug report http://bugs.debian.org/604627 :

 calling 'smartctl -d megaraid,0 /dev/sda -t short' gives:

 smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build)
 Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net
 Short offline self test failed [Cannot allocate memory]
 megasas: Failed to alloc kernel SGL buffer for IOCTL


Another user reported the same issue on the linux-ide list:
http://marc.info/?l=linux-ide&m=128941801715301
with the following backtrace:

[   69.162393] ------------[ cut here ]------------
[   69.162404] WARNING: at /build/buildd/linux-2.6.32/mm/page_alloc.c:1806 \
__alloc_pages_slowpath+0x43b/0x580() [   69.162407] Hardware name: X8DTN
[   69.162409] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb \
vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy \
pata_jmicron megaraid_sas igb dca [   69.162429] Pid: 1206, comm: smartctl Not \
tainted 2.6.32-25-server #45-Ubuntu [   69.162432] Call Trace:
[   69.162439]  [<ffffffff81065f3b>] warn_slowpath_common+0x7b/0xc0
[   69.162443]  [<ffffffff81065f94>] warn_slowpath_null+0x14/0x20
[   69.162447]  [<ffffffff810f98fb>] __alloc_pages_slowpath+0x43b/0x580
[   69.162454]  [<ffffffff8101078c>] ? __switch_to+0x1ac/0x320
[   69.162459]  [<ffffffff81057850>] ? finish_task_switch+0x50/0xe0
[   69.162463]  [<ffffffff810f9bb1>] __alloc_pages_nodemask+0x171/0x180
[   69.162468]  [<ffffffff81017536>] dma_generic_alloc_coherent+0xa6/0x160
[   69.162475]  [<ffffffff81038b01>] x86_swiotlb_alloc_coherent+0x31/0x70
[   69.162482]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.162488]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.162494]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.162500]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.162505]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.162509]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.162515]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.162518]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.162523]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.162526] ---[ end trace 6a2181b634e2abc6 ]---
[   69.162538] ------------[ cut here ]------------
[   69.162806] kernel BUG at /build/buildd/linux-2.6.32/lib/swiotlb.c:368!
[   69.163134] invalid opcode: 0000 [#1] SMP
[   69.163570] last sysfs file: \
/sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map [   69.163975] CPU 0
[   69.164227] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb \
vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy \
pata_jmicron megaraid_sas igb dca [   69.167419] Pid: 1206, comm: smartctl Tainted: G \
W  2.6.32-25-server #45-Ubuntu X8DTN [   69.167843] RIP: 0010:[<ffffffff812c4dc5>]  \
[<ffffffff812c4dc5>] map_single+0x255/0x260 [   69.168370] RSP: 0018:ffff88081c0ebc58 \
EFLAGS: 00010246 [   69.168655] RAX: 000000000003bffc RBX: 00000000ffffffff RCX: \
0000000000000002 [   69.169000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: \
ffff88001dffe000 [   69.169346] RBP: ffff88081c0ebcb8 R08: 0000000000000000 R09: \
ffff880000030840 [   69.169691] R10: 0000000000100000 R11: 0000000000000000 R12: \
0000000000000000 [   69.170036] R13: 00000000ffffffff R14: 0000000000000001 R15: \
0000000000200000 [   69.170382] FS:  00007fb8de189720(0000) GS:ffff88001de00000(0000) \
knlGS:0000000000000000 [   69.170794] CS:  0010 DS: 0000 ES: 0000 CR0: \
0000000080050033 [   69.171094] CR2: 00007fb8dd59237c CR3: 000000081a790000 CR4: \
00000000000006f0 [   69.171439] DR0: 0000000000000000 DR1: 0000000000000000 DR2: \
0000000000000000 [   69.171784] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: \
0000000000000400 [   69.172130] Process smartctl (pid: 1206, threadinfo \
ffff88081c0ea000, task ffff88081a760000) [   69.194513] Stack:
[   69.205788]  0000000000000034 00000002817e3390 0000000000000000 ffff88081c0ebe00
[   69.217739] <0> 0000000000000000 000000000003bffc 0000000000000000 \
0000000000000000 [   69.241250] <0> 0000000000000000 00000000ffffffff \
ffff88081c5b4080 ffff88081c0ebe00 [   69.277310] Call Trace:
[   69.289278]  [<ffffffff812c52ac>] swiotlb_alloc_coherent+0xec/0x130
[   69.301118]  [<ffffffff81038b31>] x86_swiotlb_alloc_coherent+0x61/0x70
[   69.313045]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.336399]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.359346]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.370902]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.382322]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.393622]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.404696]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.415761]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.426640]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.437491] Code: fe ff ff 48 8b 3d 74 38 76 00 41 bf 00 00 20 00 e8 51 f5 d7 ff \
83 e0 ff 48 05 ff 07 00 00 48 c1 e8 0b 48 89 45 c8 e9 13 fe ff ff <0f> 0b eb fe 0f 1f \
80 00 00 00 00 55 48 89 e5 48 83 ec 20 4c 89 [   69.478216] RIP  [<ffffffff812c4dc5>] \
map_single+0x255/0x260 [   69.489668]  RSP <ffff88081c0ebc58>
[   69.500975] ---[ end trace 6a2181b634e2abc7 ]---


Both users have confirmed that the patch fixes their problem. One could
of course imagine a workaround in the smartctl application so that it
never sent requests with a zero iov_len, but I still believe that
actually fixing the driver to handle such requests is better.

No?




Bjørn
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Re: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[FUJITA Tomonori]

On Wed, 19 Jan 2011 07:33:56 +0100
**UNKNOWN CHARSET** <bjorn@mork.no> wrote:

> Both users have confirmed that the patch fixes their problem. One could
> of course imagine a workaround in the smartctl application so that it
> never sent requests with a zero iov_len, but I still believe that
> actually fixing the driver to handle such requests is better.

The patch looks fine to me. dma_alloc_coherent() doesn't take zero for
the size argument (causes a kernel crash). The driver can't assume
that an applications is sane so it needs to check the size that an
application passed on.

Unfortunately, your patch can't be applied to the latest git. I think
that you need to submit the updated patch first. After it's merged,
you can send stable maintainers the modified patch that can be applied
to stable kernels.

Btw, about your patch, it's better to use "if (!hoge)" instead of "if
(hoge == 0)" and kbuff_arr[] is initialized so seems that you don't
need to reset it again. The updated patch would be something like:

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 5d6d07b..cee1d3b 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -4611,6 +4611,9 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
 	 * For each user buffer, create a mirror buffer and copy in
 	 */
 	for (i = 0; i < ioc->sge_count; i++) {
+		if (!ioc->sgl[i].iov_len)
+			continue;
+
 		kbuff_arr[i] = dma_alloc_coherent(&instance->pdev->dev,
 						    ioc->sgl[i].iov_len,
 						    &buf_handle, GFP_KERNEL);

Re: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Bjørn Mork]

FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> writes:

> The patch looks fine to me. dma_alloc_coherent() doesn't take zero for
> the size argument (causes a kernel crash). The driver can't assume
> that an applications is sane so it needs to check the size that an
> application passed on.
>
> Unfortunately, your patch can't be applied to the latest git. I think
> that you need to submit the updated patch first. After it's merged,
> you can send stable maintainers the modified patch that can be applied
> to stable kernels.
>
> Btw, about your patch, it's better to use "if (!hoge)" instead of "if
> (hoge == 0)" 

I believe that is a matter of taste, although I tend to agree that it
looks better.  I used the "(hoge == 0)" syntax to try to keep in line
with the style already used in this driver, like e.g.

static int
megasas_queue_command_lck(struct scsi_cmnd *scmd, void (*done) (struct scsi_cmnd *))
{
	struct megasas_instance *instance;
	unsigned long flags;

	instance = (struct megasas_instance *)
	    scmd->device->host->hostdata;

	if (instance->issuepend_done == 0)
		return SCSI_MLQUEUE_HOST_BUSY;



but I see now that there are quite a few "if (!hoge)" as well, so I will
update as you suggest.


> and kbuff_arr[] is initialized so seems that you don't
> need to reset it again.

Thanks.  Don't understand how I could have missed that.


> The updated patch would be something like:
>
> diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
> index 5d6d07b..cee1d3b 100644
> --- a/drivers/scsi/megaraid/megaraid_sas_base.c
> +++ b/drivers/scsi/megaraid/megaraid_sas_base.c
> @@ -4611,6 +4611,9 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
>  	 * For each user buffer, create a mirror buffer and copy in
>  	 */
>  	for (i = 0; i < ioc->sge_count; i++) {
> +		if (!ioc->sgl[i].iov_len)
> +			continue;
> +
>  		kbuff_arr[i] = dma_alloc_coherent(&instance->pdev->dev,
>  						    ioc->sgl[i].iov_len,
>  						    &buf_handle, GFP_KERNEL);


Yes, I'll followup with that in a separate mail.  Thanks a lot for your
thorough review.



Bjørn
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[PATCH v3] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Bjørn Mork]

The ioc->sgl[i].iov_len value is supplied by the ioctl caller, and can be
zero in some cases.  Assume that's valid and continue without error.

Fixes (multiple individual reports of the same problem for quite a while):

http://marc.info/?l=linux-ide&m=128941801715301
http://bugs.debian.org/604627
http://www.mail-archive.com/linux-poweredge@dell.com/msg02575.html

megasas: Failed to alloc kernel SGL buffer for IOCTL

and

[   69.162538] ------------[ cut here ]------------
[   69.162806] kernel BUG at /build/buildd/linux-2.6.32/lib/swiotlb.c:368!
[   69.163134] invalid opcode: 0000 [#1] SMP
[   69.163570] last sysfs file: /sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map
[   69.163975] CPU 0
[   69.164227] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy pata_jmicron megaraid_sas igb dca
[   69.167419] Pid: 1206, comm: smartctl Tainted: G        W  2.6.32-25-server #45-Ubuntu X8DTN
[   69.167843] RIP: 0010:[<ffffffff812c4dc5>]  [<ffffffff812c4dc5>] map_single+0x255/0x260
[   69.168370] RSP: 0018:ffff88081c0ebc58  EFLAGS: 00010246
[   69.168655] RAX: 000000000003bffc RBX: 00000000ffffffff RCX: 0000000000000002
[   69.169000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88001dffe000
[   69.169346] RBP: ffff88081c0ebcb8 R08: 0000000000000000 R09: ffff880000030840
[   69.169691] R10: 0000000000100000 R11: 0000000000000000 R12: 0000000000000000
[   69.170036] R13: 00000000ffffffff R14: 0000000000000001 R15: 0000000000200000
[   69.170382] FS:  00007fb8de189720(0000) GS:ffff88001de00000(0000) knlGS:0000000000000000
[   69.170794] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   69.171094] CR2: 00007fb8dd59237c CR3: 000000081a790000 CR4: 00000000000006f0
[   69.171439] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   69.171784] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[   69.172130] Process smartctl (pid: 1206, threadinfo ffff88081c0ea000, task ffff88081a760000)
[   69.194513] Stack:
[   69.205788]  0000000000000034 00000002817e3390 0000000000000000 ffff88081c0ebe00
[   69.217739] <0> 0000000000000000 000000000003bffc 0000000000000000 0000000000000000
[   69.241250] <0> 0000000000000000 00000000ffffffff ffff88081c5b4080 ffff88081c0ebe00
[   69.277310] Call Trace:
[   69.289278]  [<ffffffff812c52ac>] swiotlb_alloc_coherent+0xec/0x130
[   69.301118]  [<ffffffff81038b31>] x86_swiotlb_alloc_coherent+0x61/0x70
[   69.313045]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.336399]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.359346]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.370902]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.382322]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.393622]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.404696]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.415761]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.426640]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.437491] Code: fe ff ff 48 8b 3d 74 38 76 00 41 bf 00 00 20 00 e8 51 f5 d7 ff 83 e0 ff 48 05 ff 07 00 00 48 c1 e8 0b 48 89 45 c8 e9 13 fe ff ff <0f> 0b eb fe 0f 1f 80 00 00 00 00 55 48 89 e5 48 83 ec 20 4c 89
[   69.478216] RIP  [<ffffffff812c4dc5>] map_single+0x255/0x260
[   69.489668]  RSP <ffff88081c0ebc58>
[   69.500975] ---[ end trace 6a2181b634e2abc7 ]---

Reported-by: Bokhan Artem <aptem@ngs.ru>
Reported by: Marc-Christian Petersen <m.c.p@gmx.de>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
---
 drivers/scsi/megaraid/megaraid_sas_base.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/drivers/scsi/megaraid/megaraid_sas_base.c b/drivers/scsi/megaraid/megaraid_sas_base.c
index 5d6d07b..cee1d3b 100644
--- a/drivers/scsi/megaraid/megaraid_sas_base.c
+++ b/drivers/scsi/megaraid/megaraid_sas_base.c
@@ -4611,6 +4611,9 @@ megasas_mgmt_fw_ioctl(struct megasas_instance *instance,
 	 * For each user buffer, create a mirror buffer and copy in
 	 */
 	for (i = 0; i < ioc->sge_count; i++) {
+		if (!ioc->sgl[i].iov_len)
+			continue;
+
 		kbuff_arr[i] = dma_alloc_coherent(&instance->pdev->dev,
 						    ioc->sgl[i].iov_len,
 						    &buf_handle, GFP_KERNEL);
-- 
1.7.2.3

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RE: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[Benz, Michael]

Bjorn,

Please rebase your patch on 2.6.38-rc1 and resubmit. We will review it and ACK or NACK the changes, your proposed changes make sense and seem reasonable but we need to apply and test patches before we can commit the changes.

Thank you,
-Michael Benz



-----Original Message-----
From: Bjørn Mork [mailto:bjorn@mork.no] 
Sent: Tuesday, January 18, 2011 10:34 PM
To: Yang, Bo
Cc: linux-scsi@vger.kernel.org; DL-MegaRAID Linux; James E.J. Bottomley
Subject: Re: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

"Yang, Bo" <Bo.Yang@lsi.com> writes:

> If you are using megasas ioctl routine to develop your owner
> application, the best way you may need to contact with LSI for the
> tech support.

???

Thanks for answering, but I'm afraid I don't understand.  You don't fix
bugs in the driver because you don't support the application used to
trigger it?

The application in question is smartctl which is part of
http://smartmontools.sourceforge.net and AFAIK included with most (all?)
Linux distributions.  The action required to trigger the driver bug is
attempting to initiate a SMART device self test.


Quoting from the Debian bug report http://bugs.debian.org/604627 :

 calling 'smartctl -d megaraid,0 /dev/sda -t short' gives:

 smartctl 5.40 2010-07-12 r3124 [x86_64-unknown-linux-gnu] (local build)
 Copyright (C) 2002-10 by Bruce Allen, http://smartmontools.sourceforge.net
 Short offline self test failed [Cannot allocate memory]
 megasas: Failed to alloc kernel SGL buffer for IOCTL


Another user reported the same issue on the linux-ide list:
http://marc.info/?l=linux-ide&m=128941801715301
with the following backtrace:

[   69.162393] ------------[ cut here ]------------
[   69.162404] WARNING: at /build/buildd/linux-2.6.32/mm/page_alloc.c:1806 \
__alloc_pages_slowpath+0x43b/0x580() [   69.162407] Hardware name: X8DTN
[   69.162409] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb \
vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy \
pata_jmicron megaraid_sas igb dca [   69.162429] Pid: 1206, comm: smartctl Not \
tainted 2.6.32-25-server #45-Ubuntu [   69.162432] Call Trace:
[   69.162439]  [<ffffffff81065f3b>] warn_slowpath_common+0x7b/0xc0
[   69.162443]  [<ffffffff81065f94>] warn_slowpath_null+0x14/0x20
[   69.162447]  [<ffffffff810f98fb>] __alloc_pages_slowpath+0x43b/0x580
[   69.162454]  [<ffffffff8101078c>] ? __switch_to+0x1ac/0x320
[   69.162459]  [<ffffffff81057850>] ? finish_task_switch+0x50/0xe0
[   69.162463]  [<ffffffff810f9bb1>] __alloc_pages_nodemask+0x171/0x180
[   69.162468]  [<ffffffff81017536>] dma_generic_alloc_coherent+0xa6/0x160
[   69.162475]  [<ffffffff81038b01>] x86_swiotlb_alloc_coherent+0x31/0x70
[   69.162482]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.162488]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.162494]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.162500]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.162505]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.162509]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.162515]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.162518]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.162523]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.162526] ---[ end trace 6a2181b634e2abc6 ]---
[   69.162538] ------------[ cut here ]------------
[   69.162806] kernel BUG at /build/buildd/linux-2.6.32/lib/swiotlb.c:368!
[   69.163134] invalid opcode: 0000 [#1] SMP
[   69.163570] last sysfs file: \
/sys/devices/system/cpu/cpu3/cache/index2/shared_cpu_map [   69.163975] CPU 0
[   69.164227] Modules linked in: fbcon tileblit font bitblit softcursor vga16fb \
vgastate ioatdma radeon ttm drm_kms_helper shpchp drm i2c_algo_bit lp parport floppy \
pata_jmicron megaraid_sas igb dca [   69.167419] Pid: 1206, comm: smartctl Tainted: G \
W  2.6.32-25-server #45-Ubuntu X8DTN [   69.167843] RIP: 0010:[<ffffffff812c4dc5>]  \
[<ffffffff812c4dc5>] map_single+0x255/0x260 [   69.168370] RSP: 0018:ffff88081c0ebc58 \
EFLAGS: 00010246 [   69.168655] RAX: 000000000003bffc RBX: 00000000ffffffff RCX: \
0000000000000002 [   69.169000] RDX: 0000000000000000 RSI: 0000000000000000 RDI: \
ffff88001dffe000 [   69.169346] RBP: ffff88081c0ebcb8 R08: 0000000000000000 R09: \
ffff880000030840 [   69.169691] R10: 0000000000100000 R11: 0000000000000000 R12: \
0000000000000000 [   69.170036] R13: 00000000ffffffff R14: 0000000000000001 R15: \
0000000000200000 [   69.170382] FS:  00007fb8de189720(0000) GS:ffff88001de00000(0000) \
knlGS:0000000000000000 [   69.170794] CS:  0010 DS: 0000 ES: 0000 CR0: \
0000000080050033 [   69.171094] CR2: 00007fb8dd59237c CR3: 000000081a790000 CR4: \
00000000000006f0 [   69.171439] DR0: 0000000000000000 DR1: 0000000000000000 DR2: \
0000000000000000 [   69.171784] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: \
0000000000000400 [   69.172130] Process smartctl (pid: 1206, threadinfo \
ffff88081c0ea000, task ffff88081a760000) [   69.194513] Stack:
[   69.205788]  0000000000000034 00000002817e3390 0000000000000000 ffff88081c0ebe00
[   69.217739] <0> 0000000000000000 000000000003bffc 0000000000000000 \
0000000000000000 [   69.241250] <0> 0000000000000000 00000000ffffffff \
ffff88081c5b4080 ffff88081c0ebe00 [   69.277310] Call Trace:
[   69.289278]  [<ffffffff812c52ac>] swiotlb_alloc_coherent+0xec/0x130
[   69.301118]  [<ffffffff81038b31>] x86_swiotlb_alloc_coherent+0x61/0x70
[   69.313045]  [<ffffffffa002d0ce>] megasas_mgmt_fw_ioctl+0x1ae/0x690 [megaraid_sas]
[   69.336399]  [<ffffffffa002d748>] megasas_mgmt_ioctl_fw+0x198/0x240 [megaraid_sas]
[   69.359346]  [<ffffffffa002f695>] megasas_mgmt_ioctl+0x35/0x50 [megaraid_sas]
[   69.370902]  [<ffffffff81153b12>] vfs_ioctl+0x22/0xa0
[   69.382322]  [<ffffffff8115da2a>] ? alloc_fd+0x10a/0x150
[   69.393622]  [<ffffffff81153cb1>] do_vfs_ioctl+0x81/0x410
[   69.404696]  [<ffffffff8155cc13>] ? do_page_fault+0x153/0x3b0
[   69.415761]  [<ffffffff811540c1>] sys_ioctl+0x81/0xa0
[   69.426640]  [<ffffffff810121b2>] system_call_fastpath+0x16/0x1b
[   69.437491] Code: fe ff ff 48 8b 3d 74 38 76 00 41 bf 00 00 20 00 e8 51 f5 d7 ff \
83 e0 ff 48 05 ff 07 00 00 48 c1 e8 0b 48 89 45 c8 e9 13 fe ff ff <0f> 0b eb fe 0f 1f \
80 00 00 00 00 55 48 89 e5 48 83 ec 20 4c 89 [   69.478216] RIP  [<ffffffff812c4dc5>] \
map_single+0x255/0x260 [   69.489668]  RSP <ffff88081c0ebc58>
[   69.500975] ---[ end trace 6a2181b634e2abc7 ]---


Both users have confirmed that the patch fixes their problem. One could
of course imagine a workaround in the smartctl application so that it
never sent requests with a zero iov_len, but I still believe that
actually fixing the driver to handle such requests is better.

No?




Bjørn

Re: [PATCH] [SCSI] megaraid_sas: Sanity check user supplied length before passing it to dma_alloc_coherent()

[FUJITA Tomonori]

2011/1/20 Benz, Michael <Michael.Benz@lsi.com>:

> Please rebase your patch on 2.6.38-rc1 and resubmit. We will review it and ACK or NACK the changes, your proposed changes make sense and seem reasonable but we need to apply and test patches before we can commit the changes.

I think that he already did:

http://marc.info/?l=linux-scsi&m=129542804608130&w=2