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2015-10-02drm/i915/bxt: Modify BXT BLC according to VBT changesSunil Kamath
Latest VBT mentions which set of registers will be used for BLC, as controller number field. Making use of this field in BXT BLC implementation. Also, the registers are used in case control pin indicates display DDI. Adding a check for this. According to Bspec, BLC_PWM_*_2 uses the display utility pin for output. To use backlight 2, enable the utility pin with mode = PWM v2: Jani's review comments addressed - Add a prefix _ to BXT BLC registers definitions. - Add "bxt only" comment for u8 controller - Remove control_pin check for DDI controller - Check for valid controller values - Set pipe bits in UTIL_PIN_CTL - Enable/Disable UTIL_PIN_CTL in enable/disable_backlight() - If BLC 2 is used, read active_low_pwm from UTIL_PIN polarity Satheesh's review comment addressed - If UTIL PIN is already enabled, BIOS would have programmed it. No need to disable and enable again. v3: Jani's review comments - add UTIL_PIN_PIPE_MASK and UTIL_PIN_MODE_MASK - Disable UTIL_PIN if controller 1 is used - Mask out UTIL_PIN_PIPE_MASK and UTIL_PIN_MODE_MASK before enabling UTIL_PIN - check valid controller value in intel_bios.c - add backlight.util_pin_active_low - disable util pin before enabling v4: Change for BXT-PO branch: Stubbed unwanted definition which was existing before because of DC6 patch. UTIL_PIN_MODE_PWM (0x1b << 24) v2: Fixed Jani's review comment. v3: Split the backight PWM frequency programming into separate patch, in cases BIOS doesn't initializes it. v4: Starting afresh and not modifying existing state for backlight, as per Jani's recommendation. v5: Fixed Jani's review comment wrt util pin enable Signed-off-by: Vandana Kannan <vandana.kannan@intel.com> Signed-off-by: Sunil Kamath <sunil.kamath@intel.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915/bxt: get DSI pixelclockShashank Sharma
BXT's DSI PLL is different from that of VLV. So this patch adds a new function to get the current DSI pixel clock based on the PLL divider ratio and lane count. This function is required for intel_dsi_get_config() function. v2: Fixed Jani's review comments. Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915/bxt: get_hw_state for BXTShashank Sharma
Pick appropriate port control register (BXT or VLV), based on device. Get the current hw state wrt Mipi port. v2: Rebased on latest drm nightly branch. v3: Removed the GET_DSI_PORT_CTRL Macro for consistency with earlier implementations as per Jani's suggestion. Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915/bxt: DSI disable and post-disableShashank Sharma
This patch contains changes to support DSI disble sequence in BXT. The changes are: 1. BXT specific changes in clear_device_ready function. 2. BXT specific changes in DSI disable and post-disable functions. 3. Add a new function to reset BXT Dphy clock and dividers (bxt_dsi_reset_clocks). 4. Moved some part of the vlv clock reset code, in a new function (vlv_dsi_reset_clocks) maintaining the exact same sequence. 5. Wrapper function to call corresponding reset clock function. v2: Fixed Jani's review comments. v3: Removed the GET_DSI_PORT_CTRL Macro for consistency with earlier implementations as per Jani's suggestion. Signed-off-by: Uma Shankar <uma.shankar@intel.com> Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915/bxt: Program Tx Rx and Dphy clocksShashank Sharma
BXT DSI clocks are different than previous platforms. So adding a new function to program following clocks and dividers: 1. Program variable divider to generate input to Tx clock divider (Output value must be < 39.5Mhz) 2. Select divide by 2 option to get < 20Mhz for Tx clock 3. Program 8by3 divider to generate Rx clock v2: Fixed Jani's review comments. Adjusted the Macro definition as per convention. Simplified the logic for bit definitions for MIPI PORT A and PORT C in same registers. v3: Refactored the macros for TX, RX Escape and DPHY clocks as per Jani's suggestion. v4: Addressed Jani's review comments. Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915/bxt: DSI enable for BXTShashank Sharma
This patch contains following changes: 1. MIPI device ready changes to support dsi_pre_enable. Changes are specific to BXT device ready sequence. Added check for ULPS mode(No effects on VLV). 2. Changes in dsi_enable to pick BXT port control register. 3. Changes in dsi_pre_enable to restrict DPIO programming for VLV v2: Fixed Jani's review comments. Removed the changes in VLV/CHV code. Fixed the macros to get proper port offsets. v3: Rebased on latest drm-nightly branch. Fixed Jani's review comments. Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915/bxt: DSI encoder support in CRTC modesetShashank Sharma
SKL and BXT qualifies the HAS_DDI() check, and hence haswell modeset functions are re-used for modeset sequence. But DDI interface doesn't include support for DSI. This patch adds: 1. cases for DSI encoder, in those modeset functions and allows a CRTC modeset 2. Adds call to pre_pll enabled from CRTC modeset function. Nothing needs to be done as such in CRTC for DSI encoder, as PLL, clock and and transcoder programming will be taken care in encoder's pre_enable and pre_pll_enable function. v2: Fixed Jani's review comments. Added INVALID_PORT for non DDI encoder like DSI for platforms having HAS_DDI as true. v3: Rebased on latest drm-nightly branch. Added a WARN_ON for invalid encoder. v4: WARN_ON for invalid encoder is refactored as per Jani's suggestion. Fixed the sequence for pre_pll_enable. v5: Protected DDI code paths in case of DSI encoder calls. Signed-off-by: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Uma Shankar <uma.shankar@intel.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915: rename INSTDONE1 to GEN4_INSTDONE1Imre Deak
This register was added on GEN4, by the name INSTDONE_1 whereas the GEN6 specification calls it INSTDONE_2. Keep the original name with a platform prefix to make it clearer which INSTDONE register instance this is. Also add a comment about the SNB alternative name. Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02Merge tag 'mmc-v4.3-rc3' of git://git.linaro.org/people/ulf.hansson/mmcLinus Torvalds
Pull MMC fixes from Ulf Hansson: "Here are some mmc fixes intended for v4.3 rc4: MMC core: - Allow users of mmc_of_parse() to succeed when CONFIG_GPIOLIB is unset - Prevent infinite loop of re-tuning for CRC-errors for CMD19 and CMD21 MMC host: - pxamci: Fix issues with card detect - sunxi: Fix clk-delay settings" * tag 'mmc-v4.3-rc3' of git://git.linaro.org/people/ulf.hansson/mmc: mmc: core: fix dead loop of mmc_retune mmc: pxamci: fix card detect with slot-gpio API mmc: sunxi: Fix clk-delay settings mmc: core: Don't return an error for CD/WP GPIOs when GPIOLIB is unset
2015-10-02Merge git://git.infradead.org/intel-iommuLinus Torvalds
Pull IOVA fixes from David Woodhouse: "The main fix here is the first one, fixing the over-allocation of size-aligned requests. The other patches simply make the existing IOVA code available to users other than the Intel VT-d driver, with no functional change. I concede the latter really *should* have been submitted during the merge window, but since it's basically risk-free and people are waiting to build on top of it and it's my fault I didn't get it in, I (and they) would be grateful if you'd take it" * git://git.infradead.org/intel-iommu: iommu: Make the iova library a module iommu: iova: Export symbols iommu: iova: Move iova cache management to the iova library iommu/iova: Avoid over-allocating when size-aligned
2015-10-02ASoC: dwc: correct irq clear methodYitian Bu
from Designware I2S datasheet, tx/rx XRUN irq is cleared by reading register TOR/ROR, rather than by writing into them. Signed-off-by: Yitian Bu <yitian.bu@tangramtek.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
2015-10-02arm64: ftrace: fix function_graph tracer panicLi Bin
When function graph tracer is enabled, the following operation will trigger panic: mount -t debugfs nodev /sys/kernel echo next_tgid > /sys/kernel/tracing/set_ftrace_filter echo function_graph > /sys/kernel/tracing/current_tracer ls /proc/ ------------[ cut here ]------------ [ 198.501417] Unable to handle kernel paging request at virtual address cb88537fdc8ba316 [ 198.506126] pgd = ffffffc008f79000 [ 198.509363] [cb88537fdc8ba316] *pgd=00000000488c6003, *pud=00000000488c6003, *pmd=0000000000000000 [ 198.517726] Internal error: Oops: 94000005 [#1] SMP [ 198.518798] Modules linked in: [ 198.520582] CPU: 1 PID: 1388 Comm: ls Tainted: G [ 198.521800] Hardware name: linux,dummy-virt (DT) [ 198.522852] task: ffffffc0fa9e8000 ti: ffffffc0f9ab0000 task.ti: ffffffc0f9ab0000 [ 198.524306] PC is at next_tgid+0x30/0x100 [ 198.525205] LR is at return_to_handler+0x0/0x20 [ 198.526090] pc : [<ffffffc0002a1070>] lr : [<ffffffc0000907c0>] pstate: 60000145 [ 198.527392] sp : ffffffc0f9ab3d40 [ 198.528084] x29: ffffffc0f9ab3d40 x28: ffffffc0f9ab0000 [ 198.529406] x27: ffffffc000d6a000 x26: ffffffc000b786e8 [ 198.530659] x25: ffffffc0002a1900 x24: ffffffc0faf16c00 [ 198.531942] x23: ffffffc0f9ab3ea0 x22: 0000000000000002 [ 198.533202] x21: ffffffc000d85050 x20: 0000000000000002 [ 198.534446] x19: 0000000000000002 x18: 0000000000000000 [ 198.535719] x17: 000000000049fa08 x16: ffffffc000242efc [ 198.537030] x15: 0000007fa472b54c x14: ffffffffff000000 [ 198.538347] x13: ffffffc0fada84a0 x12: 0000000000000001 [ 198.539634] x11: ffffffc0f9ab3d70 x10: ffffffc0f9ab3d70 [ 198.540915] x9 : ffffffc0000907c0 x8 : ffffffc0f9ab3d40 [ 198.542215] x7 : 0000002e330f08f0 x6 : 0000000000000015 [ 198.543508] x5 : 0000000000000f08 x4 : ffffffc0f9835ec0 [ 198.544792] x3 : cb88537fdc8ba316 x2 : cb88537fdc8ba306 [ 198.546108] x1 : 0000000000000002 x0 : ffffffc000d85050 [ 198.547432] [ 198.547920] Process ls (pid: 1388, stack limit = 0xffffffc0f9ab0020) [ 198.549170] Stack: (0xffffffc0f9ab3d40 to 0xffffffc0f9ab4000) [ 198.582568] Call trace: [ 198.583313] [<ffffffc0002a1070>] next_tgid+0x30/0x100 [ 198.584359] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70 [ 198.585503] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70 [ 198.586574] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70 [ 198.587660] [<ffffffc0000907bc>] ftrace_graph_caller+0x6c/0x70 [ 198.588896] Code: aa0003f5 2a0103f4 b4000102 91004043 (885f7c60) [ 198.591092] ---[ end trace 6a346f8f20949ac8 ]--- This is because when using function graph tracer, if the traced function return value is in multi regs ([x0-x7]), return_to_handler may corrupt them. So in return_to_handler, the parameter regs should be protected properly. Cc: <stable@vger.kernel.org> # 3.18+ Signed-off-by: Li Bin <huawei.libin@huawei.com> Acked-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2015-10-02vga_switcheroo: Add missing lockingLukas Wunner
The following functions iterate over the client list, invoke client callbacks or invoke handler callbacks without locking anything at all: - Introduced by c8e9cf7bb240 ("vga_switcheroo: Add a helper function to get the client state"): vga_switcheroo_get_client_state() - Introduced by 0d69704ae348 ("gpu/vga_switcheroo: add driver control power feature. (v3)"): vga_switcheroo_set_dynamic_switch() vga_switcheroo_runtime_suspend() vga_switcheroo_runtime_resume() vga_switcheroo_runtime_resume_hdmi_audio() Refactor vga_switcheroo_runtime_resume_hdmi_audio() a bit to be able to release vgasr_mutex immediately after iterating over the client list. Signed-off-by: Lukas Wunner <lukas@wunner.de> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02MIPS: BPF: Fix load delay slots.Ralf Baechle
The entire bpf_jit_asm.S is written in noreorder mode because "we know better" according to a comment. This also prevented the assembler from throwing in the required NOPs for MIPS I processors which have no load-use interlock, thus the load's consumer might end up using the old value of the register from prior to the load. Fixed by putting the assembler in reorder mode for just the affected load instructions. This is not enough for gas to actually try to be clever by looking at the next instruction and inserting a nop only when needed but as the comment said "we know better", so getting gas to unconditionally emit a NOP is just right in this case and prevents adding further ifdefery. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-10-02x86/headers/uapi: Fix __BITS_PER_LONG value for x32 buildsBen Hutchings
On x32, gcc predefines __x86_64__ but long is only 32-bit. Use __ILP32__ to distinguish x32. Fixes this compiler error in perf: tools/include/asm-generic/bitops/__ffs.h: In function '__ffs': tools/include/asm-generic/bitops/__ffs.h:19:8: error: right shift count >= width of type [-Werror=shift-count-overflow] word >>= 32; ^ This isn't sufficient to build perf for x32, though. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1443660043.2730.15.camel@decadent.org.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-02drm/i915: rename INSTDONE to GEN2_INSTDONEImre Deak
We have a bunch of INSTDONE registers for different platforms and purposes and it's not immediately clear which instance they are just by looking at the register name. This one was added on GEN2, where it was the only INSTDONE register, so mark it as such. Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02drm/i915: remove duplicate names for the render ring INSTDONE registerImre Deak
We use 3 different names to refer to the same render ring INSTDONE register. This can be confusing when comparing two parts of the code accessing the register via different names. Although the GEN4 version's layout is different, we treat it the same way as the GEN7+ version, in that we simply read it out during error capture. So remove the duplicates and leave a comment about the GEN4 difference. Note that there is also a GEN2 version of this register, but that's on a different address so not handled in this patch. Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ben Widawsky <ben@bwidawsk.net> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-10-02md/bitmap: don't pass -1 to bitmap_storage_alloc.NeilBrown
Passing -1 to bitmap_storage_alloc() causes page->index to be set to -1, which is quite problematic. So only pass ->cluster_slot if mddev_is_clustered(). Fixes: b97e92574c0b ("Use separate bitmaps for each nodes in the cluster") Cc: stable@vger.kernel.org (v4.1+) Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02md/raid1: Avoid raid1 resync getting stuckJes Sorensen
close_sync() needs to set conf->next_resync to a large, but safe value below MaxSector and use it to determine whether or not to set start_next_window in wait_barrier() Solution suggested by Neil Brown. Reported-by: Nate Dailey <nate.dailey@stratus.com> Tested-by: Xiao Ni <xni@redhat.com> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02md: drop null test before destroy functionsJulia Lawall
Remove unneeded NULL test. The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression x; @@ -if (x != NULL) \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x); // </smpl> Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr> Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02md: clear CHANGE_PENDING in readonly arrayShaohua Li
If faulty disks of an array are more than allowed degraded number, the array enters error handling. It will be marked as read-only with MD_CHANGE_PENDING/RECOVERY_NEEDED set. But currently recovery doesn't clear CHANGE_PENDING bit for read-only array. If MD_CHANGE_PENDING is set for a raid5 array, all returned IO will be hold on a list till the bit is clear. But recovery nevery clears this bit, the IO is always in pending state and nevery finish. This has bad effects like upper layer can't get an IO error and the array can't be stopped. Fixes: c3cce6cda162 ("md/raid5: ensure device failure recorded before write request returns.") Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02md/raid0: apply base queue limits *before* disk_stack_limitsNeilBrown
Calling e.g. blk_queue_max_hw_sectors() after calls to disk_stack_limits() discards the settings determined by disk_stack_limits(). So we need to make those calls first. Fixes: 199dc6ed5179 ("md/raid0: update queue parameter in a safer location.") Cc: stable@vger.kernel.org (v2.6.35+ - please apply with 199dc6ed5179). Reported-by: Jes Sorensen <Jes.Sorensen@redhat.com> Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02md/raid5: don't index beyond end of array in need_this_block().NeilBrown
When need_this_block probably shouldn't be called when there are more than 2 failed devices, we really don't want it to try indexing beyond the end of the failed_num[] of fdev[] arrays. So limit the loops to at most 2 iterations. Reported-by: Shaohua Li <shli@fb.com> Signed-off-by: NeilBrown <neilb@suse.de>
2015-10-02raid5: update analysis state for failed stripeShaohua Li
handle_failed_stripe() makes the stripe fail, eg, all IO will return with a failure, but it doesn't update stripe_head_state. Later handle_stripe() has special handling for raid6 for handle_stripe_fill(). That check before handle_stripe_fill() doesn't skip the failed stripe and we get a kernel crash in need_this_block. This patch clear the analysis state to make sure no functions wrongly called after handle_failed_stripe() Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02md: wait for pending superblock updates before switching to read-onlyNeilBrown
If a superblock update is pending, wait for it to complete before letting md_set_readonly() switch to readonly. Otherwise we might lose important information about a device having failed. For external arrays, waiting for superblock updates can wait on user-space, so in that case, just return an error. Reported-and-tested-by: Shaohua Li <shli@fb.com> Signed-off-by: NeilBrown <neilb@suse.com>
2015-10-02x86/mm: Set NX on gap between __ex_table and rodataStephen Smalley
Unused space between the end of __ex_table and the start of rodata can be left W+x in the kernel page tables. Extend the setting of the NX bit to cover this gap by starting from text_end rather than rodata_start. Before: ---[ High Kernel Mapping ]--- 0xffffffff80000000-0xffffffff81000000 16M pmd 0xffffffff81000000-0xffffffff81600000 6M ro PSE GLB x pmd 0xffffffff81600000-0xffffffff81754000 1360K ro GLB x pte 0xffffffff81754000-0xffffffff81800000 688K RW GLB x pte 0xffffffff81800000-0xffffffff81a00000 2M ro PSE GLB NX pmd 0xffffffff81a00000-0xffffffff81b3b000 1260K ro GLB NX pte 0xffffffff81b3b000-0xffffffff82000000 4884K RW GLB NX pte 0xffffffff82000000-0xffffffff82200000 2M RW PSE GLB NX pmd 0xffffffff82200000-0xffffffffa0000000 478M pmd After: ---[ High Kernel Mapping ]--- 0xffffffff80000000-0xffffffff81000000 16M pmd 0xffffffff81000000-0xffffffff81600000 6M ro PSE GLB x pmd 0xffffffff81600000-0xffffffff81754000 1360K ro GLB x pte 0xffffffff81754000-0xffffffff81800000 688K RW GLB NX pte 0xffffffff81800000-0xffffffff81a00000 2M ro PSE GLB NX pmd 0xffffffff81a00000-0xffffffff81b3b000 1260K ro GLB NX pte 0xffffffff81b3b000-0xffffffff82000000 4884K RW GLB NX pte 0xffffffff82000000-0xffffffff82200000 2M RW PSE GLB NX pmd 0xffffffff82200000-0xffffffffa0000000 478M pmd Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov> Acked-by: Kees Cook <keescook@chromium.org> Cc: <stable@vger.kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1443704662-3138-1-git-send-email-sds@tycho.nsa.gov Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-02x86/kexec: Fix kexec crash in syscall kexec_file_load()Lee, Chun-Yi
The original bug is a page fault crash that sometimes happens on big machines when preparing ELF headers: BUG: unable to handle kernel paging request at ffffc90613fc9000 IP: [<ffffffff8103d645>] prepare_elf64_ram_headers_callback+0x165/0x260 The bug is caused by us under-counting the number of memory ranges and subsequently not allocating enough ELF header space for them. The bug is typically masked on smaller systems, because the ELF header allocation is rounded up to the next page. This patch modifies the code in fill_up_crash_elf_data() by using walk_system_ram_res() instead of walk_system_ram_range() to correctly count the max number of crash memory ranges. That's because the walk_system_ram_range() filters out small memory regions that reside in the same page, but walk_system_ram_res() does not. Here's how I found the bug: After tracing prepare_elf64_headers() and prepare_elf64_ram_headers_callback(), the code uses walk_system_ram_res() to fill-in crash memory regions information to the program header, so it counts those small memory regions that reside in a page area. But, when the kernel was using walk_system_ram_range() in fill_up_crash_elf_data() to count the number of crash memory regions, it filters out small regions. I printed those small memory regions, for example: kexec: Get nr_ram ranges. vaddr=0xffff880077592258 paddr=0x77592258, sz=0xdc0 Based on the code in walk_system_ram_range(), this memory region will be filtered out: pfn = (0x77592258 + 0x1000 - 1) >> 12 = 0x77593 end_pfn = (0x77592258 + 0xfc0 -1 + 1) >> 12 = 0x77593 end_pfn - pfn = 0x77593 - 0x77593 = 0 <=== if (end_pfn > pfn) is FALSE So, the max_nr_ranges that's counted by the kernel doesn't include small memory regions - causing us to under-allocate the required space. That causes the page fault crash that happens in a later code path when preparing ELF headers. This bug is not easy to reproduce on small machines that have few CPUs, because the allocated page aligned ELF buffer has more free space to cover those small memory regions' PT_LOAD headers. Signed-off-by: Lee, Chun-Yi <jlee@suse.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Baoquan He <bhe@redhat.com> Cc: Jiang Liu <jiang.liu@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Takashi Iwai <tiwai@suse.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1443531537-29436-1-git-send-email-jlee@suse.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-02clk: ti: dflt: fix enable_reg validity checkSuman Anna
The default clock enabling functions for TI clocks - omap2_dflt_clk_enable() and omap2_dflt_clk_disable() perform a NULL check for the enable_reg field of the clk_hw_omap structure. This enable_reg field however is merely a combination of the index of the master IP module, and the offset from the master IP module's base address. A value of 0 is perfectly valid, and the current error checking will fail in these cases. The issue was found when trying to enable the iva2_ck clock on OMAP3 platforms. So, switch the check to use IS_ERR. This correction is similar to the logic used in commit c807dbedb5e5 ("clk: ti: fix ti_clk_get_reg_addr error handling"). Fixes: 9f37e90efaf0 ("clk: ti: dflt: move support for default gate clock..") Signed-off-by: Suman Anna <s-anna@ti.com> Signed-off-by: Tero Kristo <t-kristo@ti.com>
2015-10-02clk: ti: fix dual-registration of uart4_ickBen Dooks
On the OMAP AM3517 platform the uart4_ick gets registered twice, causing any power management to /dev/ttyO3 to fail when trying to wake the device up. This solves the following oops: [] Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa09e008 [] PC is at serial_omap_pm+0x48/0x15c [] LR is at _raw_spin_unlock_irqrestore+0x30/0x5c Fixes: aafd900cab87 ("CLK: TI: add omap3 clock init file") Cc: stable@vger.kernel.org Cc: mturquette@baylibre.com Cc: sboyd@codeaurora.org Cc: linux-clk@vger.kernel.org Cc: linux-omap@vger.kernel.org Cc: linux-kernel@lists.codethink.co.uk Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Tero Kristo <t-kristo@ti.com>
2015-10-02clk: ti: clk-7xx: Remove hardwired ABE clock configurationPeter Ujfalusi
The ABE related clocks should be configured via DT and not have it wired inside of the kernel. Fixes: a74c52def9ab ("clk: ti: clk-7xx: Correct ABE DPLL configuration") Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Tero Kristo <t-kristo@ti.com>
2015-10-02Merge tag 'drm-intel-next-2015-09-11' of ↵Dave Airlie
git://anongit.freedesktop.org/drm-intel into drm-next - initialize backlight from VBT as fallback (Jani) - hpd A support from Ville - various atomic polish all over (mostly from Maarten) - first parts of virtualize gpu guest support on bdw from Zhiyuan Lv - GuC fixes from Alex - polish for the chv clocks code (Ville) - various things all over, as usual * tag 'drm-intel-next-2015-09-11' of git://anongit.freedesktop.org/drm-intel: (145 commits) drm/i915: Update DRIVER_DATE to 20150911 drm/i915: Remove one very outdated comment drm/i915: Use crtc->state for duplication. drm/i915: Do not handle a null plane state. drm/i915: Remove legacy plane updates for cursor and sprite planes. drm/i915: Use atomic state when changing cursor visibility. drm/i915: Use the atomic state in intel_update_primary_planes. drm/i915: Use the plane state in intel_crtc_info. drm/i915: Use atomic plane state in the primary plane update. drm/i915: add attached connector to hdmi container drm/i915: don't hard code vlv backlight frequency if unset drm/i915: initialize backlight max from VBT drm/i915: use pch backlight override on hsw too drm/i915/bxt: Clean up bxt_init_clock_gating drm/i915: Fix cmdparser STORE/LOAD command descriptors drm/i915: Dump pfit state as hex drm/i915: access the PP_ON_DELAYS/PP_OFF_DELAYS regs only pre GEN5 drm/i915: access the PP_CONTROL reg only pre GEN5 drm/i915: Refactor common ringbuffer allocation code drm/i915: use the yesno helper for logging ...
2015-10-02drm/dp/mst: add some defines for logical/physical portsDave Airlie
This just removes the magic number. Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm/dp/mst: drop cancel work sync in the mstb destroy path (v2)Dave Airlie
Since 9eb1e57f564d4e6e10991402726cc83fe0b9172f drm/dp/mst: make sure mst_primary mstb is valid in work function we validate the mstb structs in the work function, and doing that takes a reference. So we should never get here with the work function running using the mstb device, only if the work function hasn't run yet or is running for another mstb. So we don't need to sync the work here, this was causing lockdep spew as below. [ +0.000160] ============================================= [ +0.000001] [ INFO: possible recursive locking detected ] [ +0.000002] 3.10.0-320.el7.rhel72.stable.backport.3.x86_64.debug #1 Tainted: G W ------------ [ +0.000001] --------------------------------------------- [ +0.000001] kworker/4:2/1262 is trying to acquire lock: [ +0.000001] ((&mgr->work)){+.+.+.}, at: [<ffffffff810b29a5>] flush_work+0x5/0x2e0 [ +0.000007] but task is already holding lock: [ +0.000001] ((&mgr->work)){+.+.+.}, at: [<ffffffff810b57e4>] process_one_work+0x1b4/0x710 [ +0.000004] other info that might help us debug this: [ +0.000001] Possible unsafe locking scenario: [ +0.000002] CPU0 [ +0.000000] ---- [ +0.000001] lock((&mgr->work)); [ +0.000002] lock((&mgr->work)); [ +0.000001] *** DEADLOCK *** [ +0.000001] May be due to missing lock nesting notation [ +0.000002] 2 locks held by kworker/4:2/1262: [ +0.000001] #0: (events_long){.+.+.+}, at: [<ffffffff810b57e4>] process_one_work+0x1b4/0x710 [ +0.000004] #1: ((&mgr->work)){+.+.+.}, at: [<ffffffff810b57e4>] process_one_work+0x1b4/0x710 [ +0.000003] stack backtrace: [ +0.000003] CPU: 4 PID: 1262 Comm: kworker/4:2 Tainted: G W ------------ 3.10.0-320.el7.rhel72.stable.backport.3.x86_64.debug #1 [ +0.000001] Hardware name: LENOVO 20EGS0R600/20EGS0R600, BIOS GNET71WW (2.19 ) 02/05/2015 [ +0.000008] Workqueue: events_long drm_dp_mst_link_probe_work [drm_kms_helper] [ +0.000001] ffffffff82c26c90 00000000a527b914 ffff88046399bae8 ffffffff816fe04d [ +0.000004] ffff88046399bb58 ffffffff8110f47f ffff880461438000 0001009b840fc003 [ +0.000002] ffff880461438a98 0000000000000000 0000000804dc26e1 ffffffff824a2c00 [ +0.000003] Call Trace: [ +0.000004] [<ffffffff816fe04d>] dump_stack+0x19/0x1b [ +0.000004] [<ffffffff8110f47f>] __lock_acquire+0x115f/0x1250 [ +0.000002] [<ffffffff8110fd49>] lock_acquire+0x99/0x1e0 [ +0.000002] [<ffffffff810b29a5>] ? flush_work+0x5/0x2e0 [ +0.000002] [<ffffffff810b29ee>] flush_work+0x4e/0x2e0 [ +0.000002] [<ffffffff810b29a5>] ? flush_work+0x5/0x2e0 [ +0.000004] [<ffffffff81025905>] ? native_sched_clock+0x35/0x80 [ +0.000002] [<ffffffff81025959>] ? sched_clock+0x9/0x10 [ +0.000002] [<ffffffff810da1f5>] ? local_clock+0x25/0x30 [ +0.000002] [<ffffffff8110dca9>] ? mark_held_locks+0xb9/0x140 [ +0.000003] [<ffffffff810b4ed5>] ? __cancel_work_timer+0x95/0x160 [ +0.000002] [<ffffffff810b4ee8>] __cancel_work_timer+0xa8/0x160 [ +0.000002] [<ffffffff810b4fb0>] cancel_work_sync+0x10/0x20 [ +0.000007] [<ffffffffa0160d17>] drm_dp_destroy_mst_branch_device+0x27/0x120 [drm_kms_helper] [ +0.000006] [<ffffffffa0163968>] drm_dp_mst_link_probe_work+0x78/0xa0 [drm_kms_helper] [ +0.000002] [<ffffffff810b5850>] process_one_work+0x220/0x710 [ +0.000002] [<ffffffff810b57e4>] ? process_one_work+0x1b4/0x710 [ +0.000005] [<ffffffff810b5e5b>] worker_thread+0x11b/0x3a0 [ +0.000003] [<ffffffff810b5d40>] ? process_one_work+0x710/0x710 [ +0.000002] [<ffffffff810beced>] kthread+0xed/0x100 [ +0.000003] [<ffffffff810bec00>] ? insert_kthread_work+0x80/0x80 [ +0.000003] [<ffffffff817121d8>] ret_from_fork+0x58/0x90 v2: add flush_work. Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm/dp/mst: split connector registration into two parts (v2)Dave Airlie
In order to cache the EDID properly for tiled displays, we need to retrieve it before we register the connector with userspace, otherwise userspace can call get resources and try and get the edid before we've even cached it. This fixes some problems when hotplugging mst monitors, with X/mutter running. As mutter seems to get 0 modes for one of the monitors in the tile. v2: fix warning in radeon handle tile setting in cached path rather than get edid path. Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm/dp/mst: update the link_address_sent before sending the link address (v3)Dave Airlie
Update the state before sending the msg to close it. v2: reset value if return indicates we haven't send the msg. v3: just clean the code up. Pointed out by Adam J Richter on Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91481 Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm/dp/mst: fixup handling hotplug on port removal.Dave Airlie
output ports should always have a connector, unless in the rare case connector allocation fails in the driver. In this case we only need to teardown the pdt, and free the struct, and there is no need to send a hotplug msg. In the case were we add the port to the destroy list we need to send a hotplug if we destroy any connectors, so userspace knows to reprobe stuff. this patch also handles port->connector allocation failing which should be a rare event, but makes the code consistent. Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm/dp/mst: don't pass port into the path builder functionDave Airlie
This is unnecessary and it makes it easier to see what is needed from port. also add blank line to make things nicer. Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm/radeon: drop radeon_fb_helper_set_parAlex Deucher
It was just a wrapper around drm_fb_helper_set_par that called cursor_set2 in addition. Now that the core handles this, drop this radeon specific version. Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Reviewed-by: Michel Dänzer <michel.daenzer@amd.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-02drm: handle cursor_set2 in restore_fbdev_modeAlex Deucher
If a driver uses the cursor_set2 crtc callback rather than cursor_set, use that. This fixes the fbdev helper for drivers that use cursor_set2. Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Reviewed-by: Michel Dänzer <michel.daenzer@amd.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
2015-10-01[SMB3] Do not fall back to SMBWriteX in set_file_size error casesSteve French
The error paths in set_file_size for cifs and smb3 are incorrect. In the unlikely event that a server did not support set file info of the file size, the code incorrectly falls back to trying SMBWriteX (note that only the original core SMB Write, used for example by DOS, can set the file size this way - this actually does not work for the more recent SMBWriteX). The idea was since the old DOS SMB Write could set the file size if you write zero bytes at that offset then use that if server rejects the normal set file info call. Fortunately the SMBWriteX will never be sent on the wire (except when file size is zero) since the length and offset fields were reversed in the two places in this function that call SMBWriteX causing the fall back path to return an error. It is also important to never call an SMB request from an SMB2/sMB3 session (which theoretically would be possible, and can cause a brief session drop, although the client recovers) so this should be fixed. In practice this path does not happen with modern servers but the error fall back to SMBWriteX is clearly wrong. Removing the calls to SMBWriteX in the error paths in cifs_set_file_size Pointed out by PaX/grsecurity team Signed-off-by: Steve French <steve.french@primarydata.com> Reported-by: PaX Team <pageexec@freemail.hu> CC: Emese Revfy <re.emese@gmail.com> CC: Brad Spengler <spender@grsecurity.net> CC: Stable <stable@vger.kernel.org>
2015-10-01Merge branch 'akpm' (patches from Andrew)Linus Torvalds
Merge misc fixes from Andrew Morton: "12 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: dmapool: fix overflow condition in pool_find_page() thermal: avoid division by zero in power allocator memcg: remove pcp_counter_lock kprobes: use _do_fork() in samples to make them work again drivers/input/joystick/Kconfig: zhenhua.c needs BITREVERSE memcg: make mem_cgroup_read_stat() unsigned memcg: fix dirty page migration dax: fix NULL pointer in __dax_pmd_fault() mm: hugetlbfs: skip shared VMAs when unmapping private pages to satisfy a fault mm/slab: fix unexpected index mapping result of kmalloc_size(INDEX_NODE+1) userfaultfd: remove kernel header include from uapi header arch/x86/include/asm/efi.h: fix build failure
2015-10-01Merge tag 'pm+acpi-4.3-rc4' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI fixes from Rafael Wysocki: "These are fixes mostly, for a few changes made in this cycle (the intel_idle driver, the OPP library, the ACPI EC driver, turbostat) and for some issues that have just been discovered (ACPI PCI IRQ management, PCI power management documentation, turbostat), with a couple of cleanups on top of them. Specifics: - intel_idle driver fixup for the recently added Skylake chips support (Len Brown). - Operating Performance Points (OPP) library fix related to the recently added support for new DT bindings and a fix for a typo in a comment (Viresh Kumar, Stephen Boyd). - ACPI EC driver fix for a recently introduced memory leak in an error code path (Lv Zheng). - ACPI PCI IRQ management fix for the issue where an ISA IRQ is shared with a PCI device which requires it to be configured in a different way and may cause an interrupt storm to happen as a result with an extra ACPI SCI IRQ handling simplification on top of it (Jiang Liu). - Update of the PCI power management documentation that became outdated and started to actively confuse the readers to make it actually reflect the code (Rafael J Wysocki). - turbostat fixes including an IVB Xeon regression fix (related to the --debug command line option), Skylake adjustment for the TSC running at a frequency that doesn't match the base one exactly, and a Knights Landing quirk to account for the fact that it only updates APERF and MPERF every 1024 clock cycles plus bumping up the turbostat version number (Len Brown, Hubert Chrzaniuk)" * tag 'pm+acpi-4.3-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: tools/power turbosat: update version number tools/power turbostat: SKL: Adjust for TSC difference from base frequency tools/power turbostat: KNL workaround for %Busy and Avg_MHz tools/power turbostat: IVB Xeon: fix --debug regression ACPI / PCI: Remove duplicated penalty on SCI IRQ ACPI, PCI, irq: Do not share PCI IRQ with ISA IRQ ACPI / EC: Fix a memory leak issue in acpi_ec_query() PM / OPP: Fix typo modifcation -> modification PCI / PM: Update runtime PM documentation for PCI devices PM / OPP: of_property_count_u32_elems() can return errors intel_idle: Skylake Client Support - updated
2015-10-02PM / devfreq: fix double kfreeGeliang Tang
When device_register() fails, kfree(devfreq) is called already in devfreq_dev_release(), hence there is no need to call kfree(devfreq) in err_dev again. Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
2015-10-01Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/netLinus Torvalds
Pull networking fixes from David Miller: 1) Fix regression in SKB partial checksum handling, from Pravin B Shalar. 2) Fix VLAN inside of VXLAN handling in i40e driver, from Jesse Brandeburg. 3) Cure softlockups during accept() in SCTP, from Karl Heiss. 4) MSG_PEEK should return multiple SKBs worth of data in AF_UNIX, from Aaron Conole. 5) IPV6 erroneously ignores output interface specifier in lookup key for route lookups, fix from David Ahern. 6) In Marvell DSA driver, forward unknown frames to CPU port, from Andrew Lunn. 7) Mission flow flag initializations in some code paths, from David Ahern. * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: net: Initialize flow flags in input path net: dsa: fix preparation of a port STP update testptp: Silence compiler warnings on ppc64 net/mlx4: Handle return codes in mlx4_qp_attach_common dsa: mv88e6xxx: Enable forwarding for unknown to the CPU port skbuff: Fix skb checksum partial check. net: ipv6: Add RT6_LOOKUP_F_IFACE flag if oif is set net sysfs: Print link speed as signed integer bna: fix error handling af_unix: return data from multiple SKBs on recv() with MSG_PEEK flag af_unix: Convert the unix_sk macro to an inline function for type safety net: sctp: Don't use 64 kilobyte lookup table for four elements l2tp: protect tunnel->del_work by ref_count net/ibm/emac: bump version numbers for correct work with ethtool sctp: Prevent soft lockup when sctp_accept() is called during a timeout event sctp: Whitespace fix i40e/i40evf: check for stopped admin queue i40e: fix VLAN inside VXLAN r8169: fix handling rtl_readphy result net: hisilicon: fix handling platform_get_irq result
2015-10-01dmapool: fix overflow condition in pool_find_page()Robin Murphy
If a DMA pool lies at the very top of the dma_addr_t range (as may happen with an IOMMU involved), the calculated end address of the pool wraps around to zero, and page lookup always fails. Tweak the relevant calculation to be overflow-proof. Signed-off-by: Robin Murphy <robin.murphy@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Sumit Semwal <sumit.semwal@linaro.org> Cc: Sakari Ailus <sakari.ailus@iki.fi> Cc: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01thermal: avoid division by zero in power allocatorAndrea Arcangeli
During boot I get a div by zero Oops regression starting in v4.3-rc3. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Javi Merino <javi.merino@arm.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Daniel Kurtz <djkurtz@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01memcg: remove pcp_counter_lockGreg Thelen
Commit 733a572e66d2 ("memcg: make mem_cgroup_read_{stat|event}() iterate possible cpus instead of online") removed the last use of the per memcg pcp_counter_lock but forgot to remove the variable. Kill the vestigial variable. Signed-off-by: Greg Thelen <gthelen@google.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01kprobes: use _do_fork() in samples to make them work againPetr Mladek
Commit 3033f14ab78c ("clone: support passing tls argument via C rather than pt_regs magic") introduced _do_fork() that allowed to pass @tls parameter. The old do_fork() is defined only for architectures that are not ready to use this way and do not define HAVE_COPY_THREAD_TLS. Let's use _do_fork() in the kprobe examples to make them work again on all architectures. Signed-off-by: Petr Mladek <pmladek@suse.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thiago Macieira <thiago.macieira@intel.com> Cc: Jiri Kosina <jkosina@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01drivers/input/joystick/Kconfig: zhenhua.c needs BITREVERSEAndrew Morton
It uses bitrev8(), so it must ensure that lib/bitrev.o gets included in vmlinux. Cc: Fengguang Wu <fengguang.wu@gmail.com> Cc: yalin wang <yalin.wang2010@gmail.com> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-10-01memcg: make mem_cgroup_read_stat() unsignedGreg Thelen
mem_cgroup_read_stat() returns a page count by summing per cpu page counters. The summing is racy wrt. updates, so a transient negative sum is possible. Callers don't want negative values: - mem_cgroup_wb_stats() doesn't want negative nr_dirty or nr_writeback. This could confuse dirty throttling. - oom reports and memory.stat shouldn't show confusing negative usage. - tree_usage() already avoids negatives. Avoid returning negative page counts from mem_cgroup_read_stat() and convert it to unsigned. [akpm@linux-foundation.org: fix old typo while we're in there] Signed-off-by: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: <stable@vger.kernel.org> [4.2+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>