Dear all, Please ignore this patch for now. There seems to be a bigger bug in configfs interface for mass storage function which end up in NULL pointer dereference[1]. How to reproduce: $ cd /sys/kernel/config $ mkdir g1 $ cd g1 $ mkdir configs/c.1 $ mkdir functions/mass_storage.1 $ mkdir functions/mass_storage.1/lun.3 $ ln -s functions/mass_storage.1 configs/c.1/ $ echo "UDC_NAME" > UDC Connect to windows 7 host. I have some assumption that this bug is caused by not continuous lun's numeration. Configfs allows to create luns with random number (from 1 to 8) but mass storage specification says: "Logical Unit Numbers on the device shall be numbered contiguously starting from LUN 0 to a maximum LUN of 15 (Fh)."[2] I will do some more digging about it. Footnotes: 1- [ 82.220969] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 82.229009] pgd = c0004000 [ 82.231698] [00000000] *pgd=00000000 [ 82.235260] Internal error: Oops: 17 [#1] PREEMPT SMP ARM [ 82.240638] Modules linked in: [ 82.243681] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.0.0-rc2 #39 [ 82.249926] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 82.256003] task: c07cd2f0 ti: c07c8000 task.ti: c07c8000 [ 82.261393] PC is at composite_setup+0xe3c/0x1674 [ 82.266073] LR is at composite_setup+0xf20/0x1674 [ 82.270760] pc : [<c03510d4>] lr : [<c03511b8>] psr: 600001d3 [ 82.270760] sp : c07c9df0 ip : c0806448 fp : ed8c9c9c [ 82.282216] r10: 00000001 r9 : 00000000 r8 : edaae918 [ 82.287425] r7 : ed551cc0 r6 : 00007fff r5 : 00000000 r4 : ed799634 [ 82.293934] r3 : 00000003 r2 : 00010002 r1 : edaae918 r0 : 0000002e [ 82.300446] Flags: nZCv IRQs off FIQs off Mode SVC_32 ISA ARM Segment kernel [ 82.307910] Control: 10c5387d Table: 6bc1804a DAC: 00000015 [ 82.313638] Process swapper/0 (pid: 0, stack limit = 0xc07c8210) [ 82.319627] Stack: (0xc07c9df0 to 0xc07ca000) [ 82.323969] 9de0: 00000000 c06e65f4 00000000 c07c9f68 [ 82.332130] 9e00: 00000067 c07c59ac 000003f7 edaae918 ed8c9c98 ed799690 eca2f140 200001d3 [ 82.340289] 9e20: ee79a2d8 c07c9e88 c07c5304 ffff55db 00010002 edaae810 edaae860 eda96d50 [ 82.348448] 9e40: 00000009 ee264510 00000007 c07ca444 edaae860 c0340890 c0827a40 ffff55e0 [ 82.356607] 9e60: c0827a40 eda96e40 ee264510 edaae810 00000000 edaae860 00000007 c07ca444 [ 82.364766] 9e80: edaae860 c0354170 c03407dc c033db4c edaae810 00000000 00000000 00000010 [ 82.372925] 9ea0: 00000032 c0341670 00000000 00000000 00000001 eda96e00 00000000 00000000 [ 82.381084] 9ec0: 00000000 00000032 c0803a23 ee1aa840 00000001 c005d54c 249e2450 00000000 [ 82.389244] 9ee0: 200001d3 ee1aa840 ee1aa8a0 ed84f4c0 00000000 c07c9f68 00000067 c07c59ac [ 82.397403] 9f00: 00000000 c005d688 ee1aa840 ee1aa8a0 c07db4b4 c006009c 00000032 00000000 [ 82.405562] 9f20: 00000001 c005ce20 c07c59ac c005cf34 f002000c c07ca780 c07c9f68 00000057 [ 82.413722] 9f40: f0020000 413fc090 00000001 c00086b4 c000f804 60000053 ffffffff c07c9f9c [ 82.421880] 9f60: c0803a20 c0011fc0 00000000 00000000 c07c9fb8 c001bee0 c07ca4f0 c057004c [ 82.430040] 9f80: c07ca4fc c0803a20 c0803a20 413fc090 00000001 00000000 01000000 c07c9fb0 [ 82.438199] 9fa0: c000f800 c000f804 60000053 ffffffff 00000000 c0050e70 c0803bc0 c0783bd8 [ 82.446358] 9fc0: ffffffff ffffffff c0783664 00000000 00000000 c07b13e8 00000000 c0803e54 [ 82.454517] 9fe0: c07ca480 c07b13e4 c07ce40c 4000406a 00000000 40008074 00000000 00000000 [ 82.462689] [<c03510d4>] (composite_setup) from [<c0340890>] (s3c_hsotg_complete_setup+0xb4/0x418) [ 82.471626] [<c0340890>] (s3c_hsotg_complete_setup) from [<c0354170>] (usb_gadget_giveback_request+0xc/0x10) [ 82.481429] [<c0354170>] (usb_gadget_giveback_request) from [<c033db4c>] (s3c_hsotg_complete_request+0xcc/0x12c) [ 82.491583] [<c033db4c>] (s3c_hsotg_complete_request) from [<c0341670>] (s3c_hsotg_irq+0x4fc/0x558) [ 82.500614] [<c0341670>] (s3c_hsotg_irq) from [<c005d54c>] (handle_irq_event_percpu+0x50/0x150) [ 82.509291] [<c005d54c>] (handle_irq_event_percpu) from [<c005d688>] (handle_irq_event+0x3c/0x5c) [ 82.518145] [<c005d688>] (handle_irq_event) from [<c006009c>] (handle_fasteoi_irq+0xd4/0x18c) [ 82.526650] [<c006009c>] (handle_fasteoi_irq) from [<c005ce20>] (generic_handle_irq+0x20/0x30) [ 82.535242] [<c005ce20>] (generic_handle_irq) from [<c005cf34>] (__handle_domain_irq+0x6c/0xdc) [ 82.543923] [<c005cf34>] (__handle_domain_irq) from [<c00086b4>] (gic_handle_irq+0x2c/0x6c) [ 82.552256] [<c00086b4>] (gic_handle_irq) from [<c0011fc0>] (__irq_svc+0x40/0x74) [ 82.559716] Exception stack(0xc07c9f68 to 0xc07c9fb0) [ 82.564753] 9f60: 00000000 00000000 c07c9fb8 c001bee0 c07ca4f0 c057004c [ 82.572913] 9f80: c07ca4fc c0803a20 c0803a20 413fc090 00000001 00000000 01000000 c07c9fb0 [ 82.581069] 9fa0: c000f800 c000f804 60000053 ffffffff [ 82.586113] [<c0011fc0>] (__irq_svc) from [<c000f804>] (arch_cpu_idle+0x30/0x3c) [ 82.593491] [<c000f804>] (arch_cpu_idle) from [<c0050e70>] (cpu_startup_entry+0x128/0x1a4) [ 82.601740] [<c0050e70>] (cpu_startup_entry) from [<c0783bd8>] (start_kernel+0x350/0x3bc) [ 82.609890] Code: 0a000002 e3530005 05975010 15975008 (e5953000) [ 82.615965] ---[ end trace f57d5f599a5f1bfa ]--- 2 - http://www.usb.org/developers/docs/devclass_docs/usbmassbulk_10.pdf Best Regards, Krzysztof Opasiak > -----Original Message----- > From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb- > owner@xxxxxxxxxxxxxxx] On Behalf Of Krzysztof Opasiak > Sent: Thursday, March 19, 2015 9:18 AM > To: linux-usb@xxxxxxxxxxxxxxx; balbi@xxxxxx > Cc: m.szyprowski@xxxxxxxxxxx; andrzej.p@xxxxxxxxxxx; Krzysztof > Opasiak > Subject: [PATCH] Documentation: ABI: Fix documentation for > mass_storage function > > Luns in mass storage function are identified using their id. > While creating lun's directory user cannot choose any arbitrary > name other than arabic numeral from 1 to FSG_MAX_LUNS. > > Signed-off-by: Krzysztof Opasiak <k.opasiak@xxxxxxxxxxx> > --- > .../ABI/testing/configfs-usb-gadget-mass-storage | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/Documentation/ABI/testing/configfs-usb-gadget-mass- > storage b/Documentation/ABI/testing/configfs-usb-gadget-mass- > storage > index 9931fb0..847d63b 100644 > --- a/Documentation/ABI/testing/configfs-usb-gadget-mass-storage > +++ b/Documentation/ABI/testing/configfs-usb-gadget-mass-storage > @@ -11,10 +11,15 @@ Description: > are 2..4. Available only if > CONFIG_USB_GADGET_DEBUG_FILES is set. > > -What: /config/usb- > gadget/gadget/functions/mass_storage.name/lun.name > +What: /config/usb- > gadget/gadget/functions/mass_storage.name/lun.id > Date: Oct 2013 > KernelVersion: 3.13 > Description: > + id - arabic numeral from 1 to FSG_MAX_LUNS > + (which is 8 by default) - 1. > + lun.0 is reserved for default lun which appears while > creating > + mass_storage.name directory and cannot be removed by > the user. > + > The attributes: > > file - The path to the backing file for the LUN. > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux- > usb" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
