March 2016 - kernelnewbies@kernelnewbies.org - Kernelnewbies Mailing Lists

Re: Possible Bug
by Roger H Newell March 31, 2016

March 31, 2016

On Thu, Mar 31, 2016 at 12:18 PM, nick <xerofoify(a)gmail.com> wrote: > > > On 2016-03-31 08:34 AM, Roger H Newell wrote: >> Hi: >> >> I think I may have stumbled upon a USB bug. Before I send it off to >> one of the larger lists I thought I should run it through here to be >> sure its a bug and I have all the information. Could someone have a >> look and advise ? >> >> I was having a problem mounting up a USB drive, so I had a look at >> dmesg. The output is as follows. I'm running 4.5.0+ from gregs >> staging-testing tree. >> >> [952620.256859] usb 1-6: new high-speed USB device number 4 using ehci-pci >> [952620.389797] usb 1-6: New USB device found, idVendor=0781, idProduct=5530 >> [952620.389807] usb 1-6: New USB device strings: Mfr=1, Product=2, >> SerialNumber=3 >> [952620.389813] usb 1-6: Product: Cruzer >> [952620.389818] usb 1-6: Manufacturer: SanDisk >> [952620.389823] usb 1-6: SerialNumber: 20060876510A09733592 >> [952620.397158] BUG: unable to handle kernel NULL pointer dereference >> at 0000000000000805 >> [952620.397309] IP: [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 >> [952620.397427] PGD 3db56067 PUD cb6cd067 PMD 0 >> [952620.397511] Oops: 0000 [#1] SMP >> [952620.397573] Modules linked in: binfmt_misc snd_hda_codec_realtek >> snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel snd_hda_codec >> snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event >> snd_rawmidi snd_seq snd_seq_device snd_timer edac_mce_amd snd joydev >> kvm_amd input_leds edac_core kvm soundcore serio_raw k10temp i2c_piix4 >> 8250_fintek asus_atk0110 mac_hid irqbypass parport_pc ppdev lp parport >> autofs4 pata_acpi hid_generic usbhid hid amdkfd amd_iommu_v2 radeon >> i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt >> fb_sys_fops drm psmouse ahci pata_atiixp libahci r8169 mii wmi >> [952620.398620] CPU: 1 PID: 18445 Comm: mtp-probe Not tainted 4.5.0+ #28 >> [952620.398726] Hardware name: System manufacturer System Product >> Name/M5A78L-M LX PLUS, BIOS 0402 09/20/2011 >> [952620.398884] task: ffff88009bf68d00 ti: ffff8800499f0000 task.ti: >> ffff8800499f0000 >> [952620.399006] RIP: 0010:[<ffffffff811e636b>] [<ffffffff811e636b>] >> kmem_cache_alloc_trace+0x7b/0x1e0 >> [952620.399158] RSP: 0018:ffff8800499f3c70 EFLAGS: 00010206 >> [952620.399246] RAX: 0000000000000000 RBX: 00000000024080c0 RCX: >> 000000000ae98088 >> [952620.399362] RDX: 000000000ae98087 RSI: 00000000024080c0 RDI: >> 0000000000019b20 >> [952620.399477] RBP: ffff8800499f3cb0 R08: ffff88012fc59b20 R09: >> ffff88012b003cc0 >> [952620.399593] R10: 0000000000000805 R11: fefefefefefefeff R12: >> 00000000024080c0 >> [952620.399709] R13: ffffffff813736d3 R14: 00007f9bfa435040 R15: >> ffff88012b003cc0 >> [952620.399826] FS: 00007f550c9a48c0(0000) GS:ffff88012fc40000(0000) >> knlGS:0000000000000000 >> [952620.399956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [952620.400050] CR2: 0000000000000805 CR3: 00000000ce839000 CR4: >> 00000000000006e0 >> [952620.400165] Stack: >> [952620.400201] 00000000024080c0 ffffffff8120bb2c 0000000000000002 >> ffff88000227d500 >> [952620.400335] ffff88000227d500 ffff8800499f3ef4 00007f9bfa435040 >> ffff8800499f3de0 >> [952620.400467] ffff8800499f3cc8 ffffffff813736d3 ffffffff81c9fe80 >> ffff8800499f3ce8 >> [952620.400599] Call Trace: >> [952620.400649] [<ffffffff8120bb2c>] ? get_empty_filp+0x5c/0x1c0 >> [952620.400748] [<ffffffff813736d3>] apparmor_file_alloc_security+0x23/0x40 >> [952620.400861] [<ffffffff81335b53>] security_file_alloc+0x33/0x50 >> [952620.400961] [<ffffffff8120bb6a>] get_empty_filp+0x9a/0x1c0 >> [952620.401057] [<ffffffff812176ce>] path_openat+0x2e/0x1400 >> [952620.401149] [<ffffffff8121661a>] ? walk_component+0x3a/0x470 >> [952620.401246] [<ffffffff812146c9>] ? path_init+0x1d9/0x330 >> [952620.401339] [<ffffffff811a6e85>] ? __inc_zone_page_state+0x35/0x40 >> [952620.401444] [<ffffffff81219454>] ? putname+0x54/0x60 >> [952620.401530] [<ffffffff8121a38e>] do_filp_open+0x7e/0xe0 >> [952620.401620] [<ffffffff811e64b5>] ? kmem_cache_alloc_trace+0x1c5/0x1e0 >> [952620.401728] [<ffffffff811e629a>] ? kmem_cache_alloc+0x17a/0x1d0 >> [952620.401829] [<ffffffff812194b6>] ? getname_flags+0x56/0x1f0 >> [952620.401924] [<ffffffff81227606>] ? __alloc_fd+0x46/0x190 >> [952620.402016] [<ffffffff81208984>] do_sys_open+0x124/0x210 >> [952620.402107] [<ffffffff81207d48>] ? SyS_access+0x1e8/0x230 >> [952620.402200] [<ffffffff81208a8e>] SyS_open+0x1e/0x20 >> [952620.402286] [<ffffffff817ec736>] entry_SYSCALL_64_fastpath+0x1e/0xa8 >> [952620.402391] Code: 08 65 4c 03 05 3f 3e e2 7e 49 83 78 10 00 4d 8b >> 10 0f 84 14 01 00 00 4d 85 d2 0f 84 0b 01 00 00 49 63 41 20 48 8d 4a >> 01 49 8b 39 <49> 8b 1c 02 4c 89 d0 65 48 0f c7 0f 0f 94 c0 84 c0 74 bb >> 49 63 >> [952620.402934] RIP [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 >> [952620.403047] RSP <ffff8800499f3c70> >> [952620.403106] CR2: 0000000000000805 >> [952620.445606] ---[ end trace e7adb7015192b3a3 ]--- >> >> _______________________________________________ >> Kernelnewbies mailing list >> Kernelnewbies(a)kernelnewbies.org >> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies >> > In the fs/file_table.c file as from the root directory of your kernel tree change in the function, > get_empty_flip change these lines: > if (unlikely(error)) { > file_free(f); > return ERR_PTR(error); > } > to: > if (unlikely(error)) > return ERR_PTR(error); > and tell me if that fixes your issue. > Nick Seems to have worked, the error is is gone and I can mount the USB device. dmesg output as follows [ 32.538288] usb 1-5: new high-speed USB device number 2 using ehci-pci [ 32.671122] usb 1-5: New USB device found, idVendor=0781, idProduct=5530 [ 32.671125] usb 1-5: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 32.671126] usb 1-5: Product: Cruzer [ 32.671128] usb 1-5: Manufacturer: SanDisk [ 32.671129] usb 1-5: SerialNumber: 20060876510A09733592 [ 32.697487] usb-storage 1-5:1.0: USB Mass Storage device detected [ 32.697691] scsi host6: usb-storage 1-5:1.0 [ 32.697757] usbcore: registered new interface driver usb-storage [ 32.702641] usbcore: registered new interface driver uas [ 33.695126] scsi 6:0:0:0: Direct-Access SanDisk Cruzer 1.02 PQ: 0 ANSI: 2 [ 33.695382] sd 6:0:0:0: Attached scsi generic sg2 type 0 [ 33.696114] sd 6:0:0:0: [sdc] 7813120 512-byte logical blocks: (4.00 GB/3.73 GiB) [ 33.697739] sd 6:0:0:0: [sdc] Write Protect is off [ 33.697742] sd 6:0:0:0: [sdc] Mode Sense: 03 00 00 00 [ 33.698740] sd 6:0:0:0: [sdc] No Caching mode page found [ 33.698744] sd 6:0:0:0: [sdc] Assuming drive cache: write through [ 33.707370] sdc: sdc1 sdc2 [ 33.710732] sd 6:0:0:0: [sdc] Attached SCSI removable disk

2 1

kernel mode termios API's
by Muni Sekhar March 31, 2016

March 31, 2016

Hi, We are having customized serial port driver, it always sets the baud to 9600 (by configuring UART BAUD_RATE register) on device file open, but not updating the termios structure. The python code(pySerial) reads the termios parameter for baud rate and only sets the baud rate if it needs to. So pySerial fails to work with this driver. Is there any kernel API to update termios structure about 9600 baud on driver device open? -- Thanks, Sekhar

2 3

Possible Bug
by Roger H Newell March 31, 2016

March 31, 2016

Hi: I think I may have stumbled upon a USB bug. Before I send it off to one of the larger lists I thought I should run it through here to be sure its a bug and I have all the information. Could someone have a look and advise ? I was having a problem mounting up a USB drive, so I had a look at dmesg. The output is as follows. I'm running 4.5.0+ from gregs staging-testing tree. [952620.256859] usb 1-6: new high-speed USB device number 4 using ehci-pci [952620.389797] usb 1-6: New USB device found, idVendor=0781, idProduct=5530 [952620.389807] usb 1-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [952620.389813] usb 1-6: Product: Cruzer [952620.389818] usb 1-6: Manufacturer: SanDisk [952620.389823] usb 1-6: SerialNumber: 20060876510A09733592 [952620.397158] BUG: unable to handle kernel NULL pointer dereference at 0000000000000805 [952620.397309] IP: [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 [952620.397427] PGD 3db56067 PUD cb6cd067 PMD 0 [952620.397511] Oops: 0000 [#1] SMP [952620.397573] Modules linked in: binfmt_misc snd_hda_codec_realtek snd_hda_codec_generic snd_hda_codec_hdmi snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi snd_seq snd_seq_device snd_timer edac_mce_amd snd joydev kvm_amd input_leds edac_core kvm soundcore serio_raw k10temp i2c_piix4 8250_fintek asus_atk0110 mac_hid irqbypass parport_pc ppdev lp parport autofs4 pata_acpi hid_generic usbhid hid amdkfd amd_iommu_v2 radeon i2c_algo_bit ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm psmouse ahci pata_atiixp libahci r8169 mii wmi [952620.398620] CPU: 1 PID: 18445 Comm: mtp-probe Not tainted 4.5.0+ #28 [952620.398726] Hardware name: System manufacturer System Product Name/M5A78L-M LX PLUS, BIOS 0402 09/20/2011 [952620.398884] task: ffff88009bf68d00 ti: ffff8800499f0000 task.ti: ffff8800499f0000 [952620.399006] RIP: 0010:[<ffffffff811e636b>] [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 [952620.399158] RSP: 0018:ffff8800499f3c70 EFLAGS: 00010206 [952620.399246] RAX: 0000000000000000 RBX: 00000000024080c0 RCX: 000000000ae98088 [952620.399362] RDX: 000000000ae98087 RSI: 00000000024080c0 RDI: 0000000000019b20 [952620.399477] RBP: ffff8800499f3cb0 R08: ffff88012fc59b20 R09: ffff88012b003cc0 [952620.399593] R10: 0000000000000805 R11: fefefefefefefeff R12: 00000000024080c0 [952620.399709] R13: ffffffff813736d3 R14: 00007f9bfa435040 R15: ffff88012b003cc0 [952620.399826] FS: 00007f550c9a48c0(0000) GS:ffff88012fc40000(0000) knlGS:0000000000000000 [952620.399956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [952620.400050] CR2: 0000000000000805 CR3: 00000000ce839000 CR4: 00000000000006e0 [952620.400165] Stack: [952620.400201] 00000000024080c0 ffffffff8120bb2c 0000000000000002 ffff88000227d500 [952620.400335] ffff88000227d500 ffff8800499f3ef4 00007f9bfa435040 ffff8800499f3de0 [952620.400467] ffff8800499f3cc8 ffffffff813736d3 ffffffff81c9fe80 ffff8800499f3ce8 [952620.400599] Call Trace: [952620.400649] [<ffffffff8120bb2c>] ? get_empty_filp+0x5c/0x1c0 [952620.400748] [<ffffffff813736d3>] apparmor_file_alloc_security+0x23/0x40 [952620.400861] [<ffffffff81335b53>] security_file_alloc+0x33/0x50 [952620.400961] [<ffffffff8120bb6a>] get_empty_filp+0x9a/0x1c0 [952620.401057] [<ffffffff812176ce>] path_openat+0x2e/0x1400 [952620.401149] [<ffffffff8121661a>] ? walk_component+0x3a/0x470 [952620.401246] [<ffffffff812146c9>] ? path_init+0x1d9/0x330 [952620.401339] [<ffffffff811a6e85>] ? __inc_zone_page_state+0x35/0x40 [952620.401444] [<ffffffff81219454>] ? putname+0x54/0x60 [952620.401530] [<ffffffff8121a38e>] do_filp_open+0x7e/0xe0 [952620.401620] [<ffffffff811e64b5>] ? kmem_cache_alloc_trace+0x1c5/0x1e0 [952620.401728] [<ffffffff811e629a>] ? kmem_cache_alloc+0x17a/0x1d0 [952620.401829] [<ffffffff812194b6>] ? getname_flags+0x56/0x1f0 [952620.401924] [<ffffffff81227606>] ? __alloc_fd+0x46/0x190 [952620.402016] [<ffffffff81208984>] do_sys_open+0x124/0x210 [952620.402107] [<ffffffff81207d48>] ? SyS_access+0x1e8/0x230 [952620.402200] [<ffffffff81208a8e>] SyS_open+0x1e/0x20 [952620.402286] [<ffffffff817ec736>] entry_SYSCALL_64_fastpath+0x1e/0xa8 [952620.402391] Code: 08 65 4c 03 05 3f 3e e2 7e 49 83 78 10 00 4d 8b 10 0f 84 14 01 00 00 4d 85 d2 0f 84 0b 01 00 00 49 63 41 20 48 8d 4a 01 49 8b 39 <49> 8b 1c 02 4c 89 d0 65 48 0f c7 0f 0f 94 c0 84 c0 74 bb 49 63 [952620.402934] RIP [<ffffffff811e636b>] kmem_cache_alloc_trace+0x7b/0x1e0 [952620.403047] RSP <ffff8800499f3c70> [952620.403106] CR2: 0000000000000805 [952620.445606] ---[ end trace e7adb7015192b3a3 ]---

2 1

Re: pci device driver
by Manoj Nayak March 31, 2016

March 31, 2016

>I am completely new to this PCI device driver so I just wanted to know that >how kernel build pci_dev structure during pci initialization time. what are >the pci function are being called The sequence of routines that lead to pci device initialization. pci_legacy_init() -> pcibios_scan_root() -> pci_scan_child_bus()-> pci_scan_slot()-> pci_scan_single_device() ->pci_device_add()-> device_add(&dev->dev) -> bus_probe_device() -> device_attach() struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn) { struct pci_dev *dev; dev = pci_get_slot(bus, devfn); if (dev) { pci_dev_put(dev); return dev; } dev = pci_scan_device(bus, devfn); if (!dev) return NULL; pci_device_add(dev, bus); return dev; } /* * Read the config data for a PCI device, sanity-check it * and fill in the dev structure... */ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn) { struct pci_dev *dev; u32 l; if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000)) return NULL; dev = pci_alloc_dev(bus); if (!dev) return NULL; dev->devfn = devfn; dev->vendor = l & 0xffff; dev->device = (l >> 16) & 0xffff; pci_set_of_node(dev); if (pci_setup_device(dev)) { pci_bus_put(dev->bus); kfree(dev); return NULL; } return dev; }

1 0

Re: Reading disks sectors
by Manoj Nayak March 30, 2016

March 30, 2016

mm/page_io.c static struct bio *get_swap_bio(gfp_t gfp_flags, struct page *page, bio_end_io_t end_io) { bio = bio_alloc(gfp_flags, 1); if (bio) { bio->bi_iter.bi_sector = map_swap_page(page, &bio->bi_bdev); bio->bi_iter.bi_sector <<= PAGE_SHIFT - 9; bio->bi_iter.bi_size = PAGE_SIZE; bio->bi_end_io = end_io; } return bio; } bi_endio() calls bio->bi_end_io. One should assign a routine to bio->bi_end_io. One can wake up the thread waiting for IO in bi_end_io. For example: direct IO has assigned dio_bio_end_io routine to bio->bi_end_io fs/direct-io.c /* * The BIO completion handler simply queues the BIO up for the process-context * handler. * * During I/O bi_private points at the dio. After I/O, bi_private is used to * implement a singly-linked list of completed BIOs, at dio->bio_list. */ static void dio_bio_end_io(struct bio *bio, int error) { struct dio *dio = bio->bi_private; bio->bi_private = dio->bio_list; dio->bio_list = bio; if (--dio->refcount == 1 && dio->waiter) wake_up_process(dio->waiter); } Regards Manoj Nayak

1 0

Did PCI/IRQ allocation change significantly after 4.2 kernel?
by Rob Groner March 29, 2016

March 29, 2016

I'm investigating why our drivers no longer work correctly after the 4.2 kernel. I have verified that in the 4.4 kernel, interrupts no longer work for us as they did before. Here are the symptoms: The driver requests an IRQ, the one that is in the pci_dev structure that comes from pci_get_device(). In most cases, that IRQ is 7. The request_irq call is successful, and the driver reports that it has IRQ 7. However, interrupts never arrive after that, and eventually an exception is thrown indicating that interrupts WERE arriving at IRQ 16 and nobody responded to them. Doing this same test with a 4.2 kernel, I see that even though lspci initially reports that the board is on IRQ 7, after the driver is loaded it then reports that the board is on IRQ 16. The driver also says it is on IRQ 16, and everything works after that. Here is what I've found so far: both kernels report the board is on IRQ 7 according to lspci before the driver is loaded. After the driver is loaded, the 4.2 kernel lspci says the board is on IRQ 16 and the 4.4 kernel says it is still on IRQ 7. In both cases, the actual interrupts appear to be coming on IRQ 16 and the 4.4 kernel fails because that is not where the interrupt handler was put. I have also found that the IRQ associated with the pci_device changes during the pci_enable_device call (before the request_irq call). In the 4.2 kernel, it changes from 7 to 16, but in the 4.4 kernel it stays 7. This is the most obvious difference I've found so far between the two kernels. What I don't understand is why the request_irq call succeeds in the 4.4 kernel, yet interrupts don't arrive on IRQ 7...they go to IRQ 16 instead. I looked through the LinuxVersions on kernelnewbies.org for 4.3 and 4.4 but did not see anything that looked like it related to IRQs, pci devices, or any of that (at least, for my particular problem). Can someone direct me to the pertinent documentation about the change if it exists? I'm walking through the kernel code now to try and find why the 4.2 pci_enable changes the IRQ from 7 to 16, but the 4.4 does not. Thank you for any help. Rob Groner Senior Electronics Engineer Modules and Systems RTD Embedded Technologies, Inc. ISO 9001 and AS9100 Certified www.rtd.com<http://www.rtd.com/>

3 7

Reading disks sectors
by François March 29, 2016

March 29, 2016

Hello, I'm trying to read raw disks sectors using bio requests. I found a sample in a stackoverflow answer which seems to do exactly what I'm trying to : http://stackoverflow.com/a/17527300/51760 Reading this, a few questions came to me: 1/ The API is outdated, and bio struct no longer have bi_sector for instance. Those fields are now in bvec_iter (see http://lxr.free-electrons.com/source/include/linux/blk_types.h?v=3.19) bio struct do have bi_iter field, so I was wondering wether it's safe to populate the bi_iter directly ie: - bio->bi_sector = sector; + bio->bi_iter.bi_sector = sector; 2/ There is a generic bi_endio function in bio.c. What should readComplete implement? IMO it should just complete the "event" (of type struct completion), and then I can just call the bio_endio function provided by bio.c. Is that correct? Thanks in advance! --- François

1 0

Re: Acquiring MSI vector physical address from kernel driver
by Manoj Nayak March 29, 2016

March 29, 2016

In the following code, msi lower address, higher address and data is written to msi_desc corresponding to a msi vector. http://lxr.free-electrons.com/source/drivers/pci/msi.c#L311 We can get the msi message from irq using irq_get_msi_desc(). http://lxr.free-electrons.com/source/drivers/pci/msi.c#L349 struct msi_desc *entry = irq_get_msi_desc(irq); Regards Manoj Nayak

1 0

Re: Adding new protocol to linux.
by Manoj Nayak March 29, 2016

March 29, 2016

Hi Daniel, Some of the Network application use two connections. One connection for control channel to send commands and status update. Other connection is used for real data transfer. For example: FTP. However this needs two socket. TCP talks about out-of-band data transfer using Urgent Pointer flag and Urgent pointer offset in the tcp header. However the data transfer uses the same connection. Regards Manoj Nayak

1 0

RE: SWSUSP for arm
by Ranjith T March 28, 2016

March 28, 2016

Hi All, I have to port software suspend for IMX6 Dual lite board to reduce boot time. But I really don't know how to do that. Could somebody assist me?. Note: I have arm-none-linux-gnueabi toolcain, linux kernel version 3.14, NAND Flash can be used to store suspended image Thanks, Ranjith.T, Software Engineer.

2 1