- 14 Dec, 2014 40 commits
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Quinn Tran authored
commit 082f58ac upstream. During temporary resource starvation at lower transport layer, command is placed on queue full retry path, which expose this problem. The TCM queue full handling of SCF_TRANSPORT_TASK_SENSE currently sends the same cmd twice to lower layer. The 1st time led to cmd normal free path. The 2nd time cause Null pointer access. This regression bug was originally introduced v3.1-rc code in the following commit: commit e057f533 Author: Christoph Hellwig <hch@infradead.org> Date: Mon Oct 17 13:56:41 2011 -0400 target: remove the transport_qf_callback se_cmd callback Signed-off-by:
Quinn Tran <quinn.tran@qlogic.com> Signed-off-by:
Saurav Kashyap <saurav.kashyap@qlogic.com> Signed-off-by:
Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by:
Ben Hutchings <ben@decadent.org.uk>
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Andy Adamson authored
commit d1f456b0 upstream. Commit 2f60ea6b ("NFSv4: The NFSv4.0 client must send RENEW calls if it holds a delegation") set the NFS4_RENEW_TIMEOUT flag in nfs4_renew_state, and does not put an nfs41_proc_async_sequence call, the NFSv4.1 lease renewal heartbeat call, on the wire to renew the NFSv4.1 state if the flag was not set. The NFS4_RENEW_TIMEOUT flag is set when "now" is after the last renewal (cl_last_renewal) plus the lease time divided by 3. This is arbitrary and sometimes does the following: In normal operation, the only way a future state renewal call is put on the wire is via a call to nfs4_schedule_state_renewal, which schedules a nfs4_renew_state workqueue task. nfs4_renew_state determines if the NFS4_RENEW_TIMEOUT should be set, and the calls nfs41_proc_async_sequence, which only gets sent if the NFS4_RENEW_TIMEOUT flag is set. Then the nfs41_proc_async_sequence rpc_release function schedules another state remewal via nfs4_schedule_state_renewal. Without this change we can get into a state where an application stops accessing the NFSv4.1 share, state renewal calls stop due to the NFS4_RENEW_TIMEOUT flag _not_ being set. The only way to recover from this situation is with a clientid re-establishment, once the application resumes and the server has timed out the lease and so returns NFS4ERR_BAD_SESSION on the subsequent SEQUENCE operation. An example application: open, lock, write a file. sleep for 6 * lease (could be less) ulock, close. In the above example with NFSv4.1 delegations enabled, without this change, there are no OP_SEQUENCE state renewal calls during the sleep, and the clientid is recovered due to lease expiration on the close. This issue does not occur with NFSv4.1 delegations disabled, nor with NFSv4.0, with or without delegations enabled. Signed-off-by:
Andy Adamson <andros@netapp.com> Link: http://lkml.kernel.org/r/1411486536-23401-1-git-send-email-andros@netapp.com Fixes: 2f60ea6b (NFSv4: The NFSv4.0 client must send RENEW calls...) Signed-off-by:
Trond Myklebust <trond.myklebust@primarydata.com> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Mikulas Patocka authored
commit 5b789da8 upstream. The function bitcpy_rev has a bug that may result in screen corruption. The bug happens under these conditions: * the end of the destination area of a copy operation is aligned on a long word boundary * the end of the source area is not aligned on a long word boundary * we are copying more than one long word In this case, the variable shift is non-zero and the variable first is zero. The statements FB_WRITEL(comp(d0, FB_READL(dst), first), dst) reads the last long word of the destination and writes it back unchanged (because first is zero). Correctly, we should write the variable d0 to the last word of the destination in this case. This patch fixes the bug by introducing and extra test if first is zero. The patch also removes the references to fb_memmove in the code that is commented out because fb_memmove was removed from framebuffer subsystem. Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
Tomi Valkeinen <tomi.valkeinen@ti.com> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Mikulas Patocka authored
commit f74a289b upstream. The framebuffer code uses the current background color to fill the border when switching consoles, however, this results in inconsistent behavior. For example: - start Midnigh Commander - the border is black - switch to another console and switch back - the border is cyan - type something into the command line in mc - the border is cyan - switch to another console and switch back - the border is black - press F9 to go to menu - the border is black - switch to another console and switch back - the border is dark blue When switching to a console with Midnight Commander, the border is random color that was left selected by the slang subsystem. This patch fixes this inconsistency by always using black as the background color when switching consoles. Signed-off-by:
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Trond Myklebust authored
commit df817ba3 upstream. The current open/lock state recovery unfortunately does not handle errors such as NFS4ERR_CONN_NOT_BOUND_TO_SESSION correctly. Instead of looping, just proceeds as if the state manager is finished recovering. This patch ensures that we loop back, handle higher priority errors and complete the open/lock state recovery. Signed-off-by:
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Ondrej Zary authored
commit 6d8ca28f upstream. Currently, ata_sff_softreset is skipped for controllers with no ctl port. But that also skips ata_sff_dev_classify required for device detection. This means that libata is currently broken on controllers with no ctl port. No device connected: [ 1.872480] pata_isapnp 01:01.02: activated [ 1.889823] scsi2 : pata_isapnp [ 1.890109] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11 [ 6.888110] ata3.01: qc timeout (cmd 0xec) [ 6.888179] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5) [ 16.888085] ata3.01: qc timeout (cmd 0xec) [ 16.888147] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5) [ 46.888086] ata3.01: qc timeout (cmd 0xec) [ 46.888148] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5) [ 51.888100] ata3.00: qc timeout (cmd 0xec) [ 51.888160] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5) [ 61.888079] ata3.00: qc timeout (cmd 0xec) [ 61.888141] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5) [ 91.888089] ata3.00: qc timeout (cmd 0xec) [ 91.888152] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5) ATAPI device connected: [ 1.882061] pata_isapnp 01:01.02: activated [ 1.893430] scsi2 : pata_isapnp [ 1.893719] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11 [ 6.892107] ata3.01: qc timeout (cmd 0xec) [ 6.892171] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5) [ 16.892079] ata3.01: qc timeout (cmd 0xec) [ 16.892138] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5) [ 46.892079] ata3.01: qc timeout (cmd 0xec) [ 46.892138] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5) [ 46.908586] ata3.00: ATAPI: ACER CD-767E/O, V1.5X, max PIO2, CDB intr [ 46.924570] ata3.00: configured for PIO0 (device error ignored) [ 46.926295] scsi 2:0:0:0: CD-ROM ACER CD-767E/O 1.5X PQ: 0 ANSI: 5 [ 46.984519] sr0: scsi3-mmc drive: 6x/6x xa/form2 tray [ 46.984592] cdrom: Uniform CD-ROM driver Revision: 3.20 So don't skip ata_sff_softreset, just skip the reset part of ata_bus_softreset if the ctl port is not available. This makes IDE port on ES968 behave correctly: No device connected: [ 4.670888] pata_isapnp 01:01.02: activated [ 4.673207] scsi host2: pata_isapnp [ 4.673675] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11 [ 7.081840] Adding 2541652k swap on /dev/sda2. Priority:-1 extents:1 across:2541652k ATAPI device connected: [ 4.704362] pata_isapnp 01:01.02: activated [ 4.706620] scsi host2: pata_isapnp [ 4.706877] ata3: PATA max PIO0 cmd 0x1e8 ctl 0x0 irq 11 [ 4.872782] ata3.00: ATAPI: ACER CD-767E/O, V1.5X, max PIO2, CDB intr [ 4.888673] ata3.00: configured for PIO0 (device error ignored) [ 4.893984] scsi 2:0:0:0: CD-ROM ACER CD-767E/O 1.5X PQ: 0 ANSI: 5 [ 7.015578] Adding 2541652k swap on /dev/sda2. Priority:-1 extents:1 across:2541652k Signed-off-by:
Ondrej Zary <linux@rainbow-software.org> Signed-off-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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Willy Tarreau authored
commit 72cf9012 upstream. This fix ensures that we never meet an integer overflow while adding 255 while parsing a variable length encoding. It works differently from commit 206a81c1 ("lzo: properly check for overruns") because instead of ensuring that we don't overrun the input, which is tricky to guarantee due to many assumptions in the code, it simply checks that the cumulated number of 255 read cannot overflow by bounding this number. The MAX_255_COUNT is the maximum number of times we can add 255 to a base count without overflowing an integer. The multiply will overflow when multiplying 255 by more than MAXINT/255. The sum will overflow earlier depending on the base count. Since the base count is taken from a u8 and a few bits, it is safe to assume that it will always be lower than or equal to 2*255, thus we can always prevent any overflow by accepting two less 255 steps. This patch also reduces the CPU overhead and actually increases performance by 1.1% compared to the initial code, while the previous fix costs 3.1% (measured on x86_64). The fix needs to be backported to all currently supported stable kernels. Reported-by:
Willem Pinckaers <willem@lekkertech.net> Cc: "Don A. Bailey" <donb@securitymouse.com> Signed-off-by:
Willy Tarreau <w@1wt.eu> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Willy Tarreau authored
commit af958a38 upstream. This reverts commit 206a81c1 ("lzo: properly check for overruns"). As analysed by Willem Pinckaers, this fix is still incomplete on certain rare corner cases, and it is easier to restart from the original code. Reported-by:
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Willy Tarreau authored
commit d98a0526 upstream. Add a complete description of the LZO format as processed by the decompressor. I have not found a public specification of this format hence this analysis, which will be used to better understand the code. Cc: Willem Pinckaers <willem@lekkertech.net> Cc: "Don A. Bailey" <donb@securitymouse.com> Signed-off-by:
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Lars-Peter Clausen authored
commit 6822ee34 upstream. "raw" is the name of a channel property, but should not be part of the channel name itself. Signed-off-by:
Lars-Peter Clausen <lars@metafoo.de> Signed-off-by:
Jonathan Cameron <jic23@kernel.org> [bwh: Backported to 3.2: using IIO_CHAN() macro to initialise the structures] Signed-off-by:
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Stanislaw Gruszka authored
commit 01f7feea upstream. Two bits control TX power on BBP_R1 register. Correct the mask, otherwise we clear additional bit on BBP_R1 register, what can have unknown, possible negative effect. Signed-off-by:
Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by:
John W. Linville <linville@tuxdriver.com> Signed-off-by:
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Benjamin Coddington authored
commit 173b3afc upstream. If rpc.statd is restarted, upcalls to monitor hosts can fail with ECONNREFUSED. In that case force a lookup of statd's new port and retry the upcall. Signed-off-by:
Benjamin Coddington <bcodding@redhat.com> Signed-off-by:
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Bryan O'Donoghue authored
commit ee1b5b16 upstream. Quark x1000 advertises PGE via the standard CPUID method PGE bits exist in Quark X1000's PTEs. In order to flush an individual PTE it is necessary to reload CR3 irrespective of the PTE.PGE bit. See Quark Core_DevMan_001.pdf section 6.4.11 This bug was fixed in Galileo kernels, unfixed vanilla kernels are expected to crash and burn on this platform. Signed-off-by:
Bryan O'Donoghue <pure.logic@nexus-software.ie> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/1411514784-14885-1-git-send-email-pure.logic@nexus-software.ieSigned-off-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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David Matlack authored
commit 2ea75be3 upstream. vcpu ioctls can hang the calling thread if issued while a vcpu is running. However, invalid ioctls can happen when userspace tries to probe the kind of file descriptors (e.g. isatty() calls ioctl(TCGETS)); in that case, we know the ioctl is going to be rejected as invalid anyway and we can fail before trying to take the vcpu mutex. This patch does not change functionality, it just makes invalid ioctls fail faster. Signed-off-by:
David Matlack <dmatlack@google.com> Signed-off-by:
Paolo Bonzini <pbonzini@redhat.com> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Andy Shevchenko authored
commit 8e45ef68 upstream. Do full clean up at exit, means terminate all ongoing DMA transfers. Signed-off-by:
Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by:
Mark Brown <broonie@kernel.org> Signed-off-by:
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Andy Shevchenko authored
commit 63d84b1a upstream. commit fb57862e upstream. If the driver was compiled with DMA support, but DMA channels weren't acquired by some reason, mid_spi_dma_exit() will crash the kernel. Fixes: 7063c0d9 (spi/dw_spi: add DMA support) Signed-off-by:
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Andy Shevchenko authored
commit b41583e7 upstream. In case of 8 bit mode and DMA usage we end up with every second byte written as 0. We have to respect bits_per_word settings what this patch actually does. Signed-off-by:
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K. Y. Srinivasan authored
commit b29ef354 upstream. Minimize failures in this function by pre-allocating the buffer for posting messages. The hypercall for posting the message can fail for a number of reasons: 1. Transient resource related issues 2. Buffer alignment 3. Buffer cannot span a page boundry We address issues 2 and 3 by preallocating a per-cpu page for the buffer. Transient resource related failures are handled by retrying by the callers of this function. This patch is based on the investigation done by Dexuan Cui <decui@microsoft.com>. I would like to thank Sitsofe Wheeler <sitsofe@yahoo.com> for reporting the issue and helping in debuggging. Signed-off-by:
K. Y. Srinivasan <kys@microsoft.com> Reported-by:
Sitsofe Wheeler <sitsofe@yahoo.com> Tested-by:
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K. Y. Srinivasan authored
commit 98d731bb upstream. Eliminate calls to BUG_ON() in vmbus_close_internal(). We have chosen to potentially leak memory, than crash the guest in case of failures. In this version of the patch I have addressed comments from Dan Carpenter (dan.carpenter@oracle.com). Signed-off-by:
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K. Y. Srinivasan authored
commit 45d727ce upstream. Fix a bug in vmbus_open() and properly propagate the error. I would like to thank Dexuan Cui <decui@microsoft.com> for identifying the issue. Signed-off-by:
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K. Y. Srinivasan authored
commit 72c6b71c upstream. Eliminate the call to BUG_ON() by waiting for the host to respond. We are trying to reclaim the ownership of memory that was given to the host and so we will have to wait until the host responds. Signed-off-by:
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K. Y. Srinivasan authored
commit 66be6530 upstream. Eliminate calls to BUG_ON() by properly handling errors. In cases where rollback is possible, we will return the appropriate error to have the calling code decide how to rollback state. In the case where we are transferring ownership of the guest physical pages to the host, we will wait for the host to respond. Signed-off-by:
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K. Y. Srinivasan authored
commit fdeebcc6 upstream. Posting messages to the host can fail because of transient resource related failures. Correctly deal with these failures and increase the number of attempts to post the message before giving up. In this version of the patch, I have normalized the error code to Linux error code. Signed-off-by:
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Kees Cook authored
commit 471b095d upstream. An empty firmware request name will trigger warnings when building device names. Make sure this is caught earlier and rejected. The warning was visible via the test_firmware.ko module interface: echo -ne "\x00" > /sys/devices/virtual/misc/test_firmware/trigger_request Reported-by:
Sasha Levin <sasha.levin@oracle.com> Signed-off-by:
Kees Cook <keescook@chromium.org> Tested-by:
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Lu Baolu authored
commit ddbe1fca upstream. This full-speed USB device generates spurious remote wakeup event as soon as USB_DEVICE_REMOTE_WAKEUP feature is set. As the result, Linux can't enter system suspend and S0ix power saving modes once this keyboard is used. This patch tries to introduce USB_QUIRK_IGNORE_REMOTE_WAKEUP quirk. With this quirk set, wakeup capability will be ignored during device configure. This patch could be back-ported to kernels as old as 2.6.39. Signed-off-by:
Lu Baolu <baolu.lu@linux.intel.com> Acked-by:
Alan Stern <stern@rowland.harvard.edu> Signed-off-by:
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Joonyoung Shim authored
commit 526a4045 upstream. The usb device will autoresume from choose_wakeup() if it is autosuspended with the wrong wakeup setting, but below errors occur because usb3503 misc driver will switch to standby mode when suspended. As add USB_QUIRK_RESET_RESUME, it can stop setting wrong wakeup from autosuspend_check(). [ 7.734717] usb 1-3: reset high-speed USB device number 3 using exynos-ehci [ 7.854658] usb 1-3: device descriptor read/64, error -71 [ 8.079657] usb 1-3: device descriptor read/64, error -71 [ 8.294664] usb 1-3: reset high-speed USB device number 3 using exynos-ehci [ 8.414658] usb 1-3: device descriptor read/64, error -71 [ 8.639657] usb 1-3: device descriptor read/64, error -71 [ 8.854667] usb 1-3: reset high-speed USB device number 3 using exynos-ehci [ 9.264598] usb 1-3: device not accepting address 3, error -71 [ 9.374655] usb 1-3: reset high-speed USB device number 3 using exynos-ehci [ 9.784601] usb 1-3: device not accepting address 3, error -71 [ 9.784838] usb usb1-port3: device 1-3 not suspended yet Signed-off-by:
Joonyoung Shim <jy0922.shim@samsung.com> Signed-off-by:
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Maciej Matraszek authored
commit 3bacc10c upstream. Fix clamp_align() used in v4l_bound_align_image() to prevent overflow when passed large value like UINT32_MAX. In the current implementation: clamp_align(UINT32_MAX, 8, 8192, 3) returns 8, because in line: x = (x + (1 << (align - 1))) & mask; x overflows to (-1 + 4) & 0x7 = 3, while expected value is 8192. v4l_bound_align_image() is heavily used in VIDIOC_S_FMT and VIDIOC_SUBDEV_S_FMT ioctls handlers, and documentation of the latter explicitly states that: "The modified format should be as close as possible to the original request." -- http://linuxtv.org/downloads/v4l-dvb-apis/vidioc-subdev-g-fmt.html Thus one would expect, that passing UINT32_MAX as format width and height will result in setting maximum possible resolution for the device. Particularly, when the driver doesn't support VIDIOC_ENUM_FRAMESIZES ioctl, which is common in the codebase. Fixes changeset: b0d3159bSigned-off-by:
Maciej Matraszek <m.matraszek@samsung.com> Acked-by:
Sakari Ailus <sakari.ailus@linux.intel.com> Signed-off-by:
Mauro Carvalho Chehab <mchehab@osg.samsung.com> [bwh: Backported to 3.2: adjust filename] Signed-off-by:
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Ricardo Ribalda Delgado authored
commit 89ec3dcf upstream. Some implementations of modprobe fail to load the driver for a PCI device automatically because the "interface" part of the modalias from the kernel is lowercase, and the modalias from file2alias is uppercase. The "interface" is the low-order byte of the Class Code, defined in PCI r3.0, Appendix D. Most interface types defined in the spec do not use alpha characters, so they won't be affected. For example, 00h, 01h, 10h, 20h, etc. are unaffected. Print the "interface" byte of the Class Code in uppercase hex, as we already do for the Vendor ID, Device ID, Class, etc. [bhelgaas: changelog] Signed-off-by:
Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by:
Bjorn Helgaas <bhelgaas@google.com> Acked-by:
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Andreas Bomholtz authored
commit dee80ad1 upstream. Added the Seluxit ApS USB Serial Dongle to cp210x driver. Signed-off-by:
Andreas Bomholtz <andreas@seluxit.com> Signed-off-by:
Johan Hovold <johan@kernel.org> Signed-off-by:
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Joe Savage authored
commit bfc2d7df upstream. Added support for Ketra N1 wireless interface, which uses the Silicon Labs' CP2104 USB to UART bridge with customized PID 8946. Signed-off-by:
Joe Savage <joe.savage@goketra.com> Signed-off-by:
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Paul Fertser authored
commit 62ea864f upstream. As reported on [1], this device needs this quirk to be able to reliably initialise the webcam. [1] http://ubuntuforums.org/showthread.php?t=2145996Signed-off-by:
Paul Fertser <fercerpav@gmail.com> Signed-off-by:
Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by:
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Jan Kara authored
commit 279bf6d3 upstream. The check whether quota format is set even though there are no quota files with journalled quota is pointless and it actually makes it impossible to turn off journalled quotas (as there's no way to unset journalled quota format). Just remove the check. Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
Theodore Ts'o <tytso@mit.edu> Signed-off-by:
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Douglas Lehr authored
commit 9fe373f9 upstream. The Crocodile chip occasionally comes up with 4k and 8k BAR sizes. Due to an erratum, setting the SR-IOV page size causes the physical function BARs to expand to the system page size. Since ppc64 uses 64k pages, when Linux tries to assign the smaller resource sizes to the now 64k BARs the address will be truncated and the BARs will overlap. Force Linux to allocate the resource as a full page, which avoids the overlap. [bhelgaas: print expanded resource, too] Signed-off-by:
Douglas Lehr <dllehr@us.ibm.com> Signed-off-by:
Anton Blanchard <anton@samba.org> Signed-off-by:
Milton Miller <miltonm@us.ibm.com> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Andreas Noever authored
commit bceee4a9 upstream. pciehp assumes that dev->subordinate, the struct pci_bus for a bridge's secondary bus, exists. But we do not create that bus if we run out of bus numbers during enumeration. This leads to a NULL dereference in init_slot() (and other places). Change pciehp_probe() to return -ENODEV when no secondary bus is present. Signed-off-by:
Andreas Noever <andreas.noever@gmail.com> Signed-off-by:
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Darrick J. Wong authored
commit a0626e75 upstream. When loading extended attributes, check each entry's value offset to make sure it doesn't collide with the entries. Without this check it is easy to crash the kernel by mounting a malicious FS containing a file with an EA wherein e_value_offs = 0 and e_value_size > 0 and then deleting the EA, which corrupts the name list. (See the f_ea_value_crash test's FS image in e2fsprogs for an example.) Signed-off-by:
Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by:
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Christian Borntraeger authored
commit f346026e upstream. We must not fallthrough if the conditions for external call are not met. Signed-off-by:
Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by:
Thomas Huth <thuth@linux.vnet.ibm.com> Signed-off-by:
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Champion Chen authored
commit 85560c4a upstream. Suspend could fail for some platforms because btusb_suspend==> btusb_stop_traffic ==> usb_kill_anchored_urbs. When btusb_bulk_complete returns before system suspend and resubmits an URB, the system cannot enter suspend state. Signed-off-by:
Champion Chen <champion_chen@realsil.com.cn> Signed-off-by:
Larry Finger <Larry.Finger@lwfinger.net> Signed-off-by:
Marcel Holtmann <marcel@holtmann.org> Signed-off-by:
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Artem Bityutskiy authored
commit ba29e721 upstream. Hu (hujianyang <hujianyang@huawei.com>) discovered an issue in the 'empty_log_bytes()' function, which calculates how many bytes are left in the log: " If 'c->lhead_lnum + 1 == c->ltail_lnum' and 'c->lhead_offs == c->leb_size', 'h' would equalent to 't' and 'empty_log_bytes()' would return 'c->log_bytes' instead of 0. " At this point it is not clear what would be the consequences of this, and whether this may lead to any problems, but this patch addresses the issue just in case. Tested-by:
hujianyang <hujianyang@huawei.com> Reported-by:
Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Signed-off-by:
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Artem Bityutskiy authored
commit 052c2807 upstream. Hu (hujianyang@huawei.com) discovered a race condition which may lead to a situation when UBIFS is unable to mount the file-system after an unclean reboot. The problem is theoretical, though. In UBIFS, we have the log, which basically a set of LEBs in a certain area. The log has the tail and the head. Every time user writes data to the file-system, the UBIFS journal grows, and the log grows as well, because we append new reference nodes to the head of the log. So the head moves forward all the time, while the log tail stays at the same position. At any time, the UBIFS master node points to the tail of the log. When we mount the file-system, we scan the log, and we always start from its tail, because this is where the master node points to. The only occasion when the tail of the log changes is the commit operation. The commit operation has 2 phases - "commit start" and "commit end". The former is relatively short, and does not involve much I/O. During this phase we mostly just build various in-memory lists of the things which have to be written to the flash media during "commit end" phase. During the commit start phase, what we do is we "clean" the log. Indeed, the commit operation will index all the data in the journal, so the entire journal "disappears", and therefore the data in the log become unneeded. So we just move the head of the log to the next LEB, and write the CS node there. This LEB will be the tail of the new log when the commit operation finishes. When the "commit start" phase finishes, users may write more data to the file-system, in parallel with the ongoing "commit end" operation. At this point the log tail was not changed yet, it is the same as it had been before we started the commit. The log head keeps moving forward, though. The commit operation now needs to write the new master node, and the new master node should point to the new log tail. After this the LEBs between the old log tail and the new log tail can be unmapped and re-used again. And here is the possible problem. We do 2 operations: (a) We first update the log tail position in memory (see 'ubifs_log_end_commit()'). (b) And then we write the master node (see the big lock of code in 'do_commit()'). But nothing prevents the log head from moving forward between (a) and (b), and the log head may "wrap" now to the old log tail. And when the "wrap" happens, the contends of the log tail gets erased. Now a power cut happens and we are in trouble. We end up with the old master node pointing to the old tail, which was erased. And replay fails because it expects the master node to point to the correct log tail at all times. This patch merges the abovementioned (a) and (b) operations by moving the master node change code to the 'ubifs_log_end_commit()' function, so that it runs with the log mutex locked, which will prevent the log from being changed benween operations (a) and (b). Reported-by:
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Artem Bityutskiy authored
commit 07e19dff upstream. The 'mst_mutex' is not needed since because 'ubifs_write_master()' is only called on the mount path and commit path. The mount path is sequential and there is no parallelism, and the commit path is also serialized - there is only one commit going on at a time. Signed-off-by:
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