- 28 Aug, 2017 6 commits
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Rafael J. Wysocki authored
Reorganize the power management part of admin-guide by adding a description of major power management strategies supported by the kernel (system-wide and working-state power management) to it and dividing the rest of the material into the system-wide PM and working-state PM chapters. On top of that, add a description of system sleep states to the system-wide PM chapter. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Lukas Wunner <lukas@wunner.de>
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Linus Torvalds authored
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommuLinus Torvalds authored
Pull IOMMU fix from Joerg Roedel: "Another fix, this time in common IOMMU sysfs code. In the conversion from the old iommu sysfs-code to the iommu_device_register interface, I missed to update the release path for the struct device associated with an IOMMU. It freed the 'struct device', which was a pointer before, but is now embedded in another struct. Freeing from the middle of allocated memory had all kinds of nasty side effects when an IOMMU was unplugged. Unfortunatly nobody unplugged and IOMMU until now, so this was not discovered earlier. The fix is to make the 'struct device' a pointer again" * tag 'iommu-fixes-v4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: iommu: Fix wrong freeing of iommu_device->dev
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-miscLinus Torvalds authored
Pull char/misc fix from Greg KH: "Here is a single misc driver fix for 4.13-rc7. It resolves a reported problem in the Android binder driver due to previous patches in 4.13-rc. It's been in linux-next with no reported issues" * tag 'char-misc-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: ANDROID: binder: fix proc->tsk check.
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/stagingLinus Torvalds authored
Pull staging/iio fixes from Greg KH: "Here are few small staging driver fixes, and some more IIO driver fixes for 4.13-rc7. Nothing major, just resolutions for some reported problems. All of these have been in linux-next with no reported problems" * tag 'staging-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: iio: magnetometer: st_magn: remove ihl property for LSM303AGR iio: magnetometer: st_magn: fix status register address for LSM303AGR iio: hid-sensor-trigger: Fix the race with user space powering up sensors iio: trigger: stm32-timer: fix get trigger mode iio: imu: adis16480: Fix acceleration scale factor for adis16480 PATCH] iio: Fix some documentation warnings staging: rtl8188eu: add RNX-N150NUB support Revert "staging: fsl-mc: be consistent when checking strcmp() return" iio: adc: stm32: fix common clock rate iio: adc: ina219: Avoid underflow for sleeping time iio: trigger: stm32-timer: add enable attribute iio: trigger: stm32-timer: fix get/set down count direction iio: trigger: stm32-timer: fix write_raw return value iio: trigger: stm32-timer: fix quadrature mode get routine iio: bmp280: properly initialize device for humidity reading
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git://github.com/jonmason/ntbLinus Torvalds authored
Pull NTB fixes from Jon Mason: "NTB bug fixes to address an incorrect ntb_mw_count reference in the NTB transport, improperly bringing down the link if SPADs are corrupted, and an out-of-order issue regarding link negotiation and data passing" * tag 'ntb-4.13-bugfixes' of git://github.com/jonmason/ntb: ntb: ntb_test: ensure the link is up before trying to configure the mws ntb: transport shouldn't disable link due to bogus values in SPADs ntb: use correct mw_count function in ntb_tool and ntb_transport
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- 27 Aug, 2017 3 commits
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Linus Torvalds authored
The "lock_page_killable()" function waits for exclusive access to the page lock bit using the WQ_FLAG_EXCLUSIVE bit in the waitqueue entry set. That means that if it gets woken up, other waiters may have been skipped. That, in turn, means that if it sees the page being unlocked, it *must* take that lock and return success, even if a lethal signal is also pending. So instead of checking for lethal signals first, we need to check for them after we've checked the actual bit that we were waiting for. Even if that might then delay the killing of the process. This matches the order of the old "wait_on_bit_lock()" infrastructure that the page locking used to use (and is still used in a few other areas). Note that if we still return an error after having unsuccessfully tried to acquire the page lock, that is ok: that means that some other thread was able to get ahead of us and lock the page, and when that other thread then unlocks the page, the wakeup event will be repeated. So any other pending waiters will now get properly woken up. Fixes: 62906027 ("mm: add PageWaiters indicating tasks are waiting for a page bit") Cc: Nick Piggin <npiggin@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Jan Kara <jack@suse.cz> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds authored
Tim Chen and Kan Liang have been battling a customer load that shows extremely long page wakeup lists. The cause seems to be constant NUMA migration of a hot page that is shared across a lot of threads, but the actual root cause for the exact behavior has not been found. Tim has a patch that batches the wait list traversal at wakeup time, so that we at least don't get long uninterruptible cases where we traverse and wake up thousands of processes and get nasty latency spikes. That is likely 4.14 material, but we're still discussing the page waitqueue specific parts of it. In the meantime, I've tried to look at making the page wait queues less expensive, and failing miserably. If you have thousands of threads waiting for the same page, it will be painful. We'll need to try to figure out the NUMA balancing issue some day, in addition to avoiding the excessive spinlock hold times. That said, having tried to rewrite the page wait queues, I can at least fix up some of the braindamage in the current situation. In particular: (a) we don't want to continue walking the page wait list if the bit we're waiting for already got set again (which seems to be one of the patterns of the bad load). That makes no progress and just causes pointless cache pollution chasing the pointers. (b) we don't want to put the non-locking waiters always on the front of the queue, and the locking waiters always on the back. Not only is that unfair, it means that we wake up thousands of reading threads that will just end up being blocked by the writer later anyway. Also add a comment about the layout of 'struct wait_page_key' - there is an external user of it in the cachefiles code that means that it has to match the layout of 'struct wait_bit_key' in the two first members. It so happens to match, because 'struct page *' and 'unsigned long *' end up having the same values simply because the page flags are the first member in struct page. Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: Kan Liang <kan.liang@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Christopher Lameter <cl@linux.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Linus Torvalds authored
We have a MAX_LFS_FILESIZE macro that is meant to be filled in by filesystems (and other IO targets) that know they are 64-bit clean and don't have any 32-bit limits in their IO path. It turns out that our 32-bit value for that limit was bogus. On 32-bit, the VM layer is limited by the page cache to only 32-bit index values, but our logic for that was confusing and actually wrong. We used to define that value to (((loff_t)PAGE_SIZE << (BITS_PER_LONG-1))-1) which is actually odd in several ways: it limits the index to 31 bits, and then it limits files so that they can't have data in that last byte of a page that has the highest 31-bit index (ie page index 0x7fffffff). Neither of those limitations make sense. The index is actually the full 32 bit unsigned value, and we can use that whole full page. So the maximum size of the file would logically be "PAGE_SIZE << BITS_PER_LONG". However, we do wan tto avoid the maximum index, because we have code that iterates over the page indexes, and we don't want that code to overflow. So the maximum size of a file on a 32-bit host should actually be one page less than the full 32-bit index. So the actual limit is ULONG_MAX << PAGE_SHIFT. That means that we will not actually be using the page of that last index (ULONG_MAX), but we can grow a file up to that limit. The wrong value of MAX_LFS_FILESIZE actually caused problems for Doug Nazar, who was still using a 32-bit host, but with a 9.7TB 2 x RAID5 volume. It turns out that our old MAX_LFS_FILESIZE was 8TiB (well, one byte less), but the actual true VM limit is one page less than 16TiB. This was invisible until commit c2a9737f ("vfs,mm: fix a dead loop in truncate_inode_pages_range()"), which started applying that MAX_LFS_FILESIZE limit to block devices too. NOTE! On 64-bit, the page index isn't a limiter at all, and the limit is actually just the offset type itself (loff_t), which is signed. But for clarity, on 64-bit, just use the maximum signed value, and don't make people have to count the number of 'f' characters in the hex constant. So just use LLONG_MAX for the 64-bit case. That was what the value had been before too, just written out as a hex constant. Fixes: c2a9737f ("vfs,mm: fix a dead loop in truncate_inode_pages_range()") Reported-and-tested-by: Doug Nazar <nazard@nazar.ca> Cc: Andreas Dilger <adilger@dilger.ca> Cc: Mark Fasheh <mfasheh@versity.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Dave Kleikamp <shaggy@kernel.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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- 26 Aug, 2017 13 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/dtor/inputLinus Torvalds authored
Pull input fixes from Dmitry Torokhov: - a tweak to the IBM Trackpoint driver that helps recognizing trackpoints on never Lenovo Carbons - a fix to the ALPS driver solving scroll issues on some Dells - yet another ACPI ID has been added to Elan I2C toucpad driver - quieted diagnostic message in soc_button_array driver * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input: Input: ALPS - fix two-finger scroll breakage in right side on ALPS touchpad Input: soc_button_array - silence -ENOENT error on Dell XPS13 9365 Input: trackpoint - add new trackpoint firmware ID Input: elan_i2c - add ELAN0602 ACPI ID to support Lenovo Yoga310
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git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pciLinus Torvalds authored
Pull PCI fix from Bjorn Helgaas: "Remove needlessly alarming MSI affinity warning (this is not actually a bug fix, but the warning prompts unnecessary bug reports)" * tag 'pci-v4.13-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: PCI/MSI: Don't warn when irq_create_affinity_masks() returns NULL
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull x86 fixes from Ingo Molnar: "Two fixes: one for an ldt_struct handling bug and a cherry-picked objtool fix" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/mm: Fix use-after-free of ldt_struct objtool: Fix '-mtune=atom' decoding support in objtool 2.0
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull timer fix from Ingo Molnar: "Fix a timer granularity handling race+bug, which would manifest itself by spuriously increasing timeouts of some timers (from 1 jiffy to ~500 jiffies in the worst case measured) in certain nohz states" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: timers: Fix excessive granularity of new timers after a nohz idle
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tipLinus Torvalds authored
Pull perf fix from Ingo Molnar: "A single fix to not allow nonsensical event groups that result in kernel warnings" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: Fix group {cpu,task} validation
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Linus Torvalds authored
Merge misc fixes from Andrew Morton: "6 fixes" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: mm/memblock.c: reversed logic in memblock_discard() fork: fix incorrect fput of ->exe_file causing use-after-free mm/madvise.c: fix freeing of locked page with MADV_FREE dax: fix deadlock due to misaligned PMD faults mm, shmem: fix handling /sys/kernel/mm/transparent_hugepage/shmem_enabled PM/hibernate: touch NMI watchdog when creating snapshot
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git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds authored
Pull Paolo Bonzini: "Bugfixes for x86, PPC and s390" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: PPC: Book3S: Fix race and leak in kvm_vm_ioctl_create_spapr_tce() KVM, pkeys: do not use PKRU value in vcpu->arch.guest_fpu.state KVM: x86: simplify handling of PKRU KVM: x86: block guest protection keys unless the host has them enabled KVM: PPC: Book3S HV: Add missing barriers to XIVE code and document them KVM: PPC: Book3S HV: Workaround POWER9 DD1.0 bug causing IPB bit loss KVM: PPC: Book3S HV: Use msgsync with hypervisor doorbells on POWER9 KVM: s390: sthyi: fix specification exception detection KVM: s390: sthyi: fix sthyi inline assembly
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git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostLinus Torvalds authored
Pull virtio fixes from Michael Tsirkin: "Fixes two obvious bugs in virtio pci" * tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio_pci: fix cpu affinity support virtio_blk: fix incorrect message when disk is resized
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git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linuxLinus Torvalds authored
Pull powerpc fix from Michael Ellerman: "Just one fix, to add a barrier in the switch_mm() code to make sure the mm cpumask update is ordered vs the MMU starting to load translations. As far as we know no one's actually hit the bug, but that's just luck. Thanks to Benjamin Herrenschmidt, Nicholas Piggin" * tag 'powerpc-4.13-8' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: powerpc/mm: Ensure cpumask update is ordered
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git://linux-nfs.org/~bfields/linuxLinus Torvalds authored
Pull nfsd fixes from Bruce Fields: "Two nfsd bugfixes, neither 4.13 regressions, but both potentially serious" * tag 'nfsd-4.13-2' of git://linux-nfs.org/~bfields/linux: net: sunrpc: svcsock: fix NULL-pointer exception nfsd: Limit end of page list when decoding NFSv4 WRITE
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git://git.samba.org/sfrench/cifs-2.6Linus Torvalds authored
Pull cifs fixes from Steve French: "Some bug fixes for stable for cifs" * tag 'cifs-fixes-for-4.13-rc6-and-stable' of git://git.samba.org/sfrench/cifs-2.6: cifs: return ENAMETOOLONG for overlong names in cifs_open()/cifs_lookup() cifs: Fix df output for users with quota limits
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git://git.infradead.org/linux-mtdLinus Torvalds authored
Pull MTD fixes from Brian Norris: "Two fixes - one for a 4.13 regression, and the other for an older one: - Atmel NAND: since we started utilizing ONFI timings, we found that we were being too restrict at rejecting them, partly due to discrepancies in ONFI 4.0 and earlier versions. Relax the restriction to keep these platforms booting. This is a 4.13-rc1 regression. - nandsim: repeated probe/removal may not work after a failed init, because we didn't free up our debugfs files properly on the failure path. This has been around since 3.8, but it's nice to get this fixed now in a nice easy patch that can target -stable, since there's already refactoring work (that also fixes the issue) targeted for the next merge window" * tag 'for-linus-20170825' of git://git.infradead.org/linux-mtd: mtd: nand: atmel: Relax tADL_min constraint mtd: nandsim: remove debugfs entries in error path
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git://git.kernel.dk/linux-blockLinus Torvalds authored
Pull block fixes from Jens Axboe: "A small batch of fixes that should be included for the 4.13 release. This contains: - Revert of the 4k loop blocksize support. Even with a recent batch of 4 fixes, we're still not really happy with it. Rather than be stuck with an API issue, let's revert it and get it right for 4.14. - Trivial patch from Bart, adding a few flags to the blk-mq debugfs exports that were added in this release, but not to the debugfs parts. - Regression fix for bsg, fixing a potential kernel panic. From Benjamin. - Tweak for the blk throttling, improving how we account discards. From Shaohua" * 'for-linus' of git://git.kernel.dk/linux-block: blk-mq-debugfs: Add names for recently added flags bsg-lib: fix kernel panic resulting from missing allocation of reply-buffer Revert "loop: support 4k physical blocksize" blk-throttle: cap discard request size
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- 25 Aug, 2017 18 commits
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git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linuxLinus Torvalds authored
Pull i2c fixes from Wolfram Sang: "I2C has some bugfixes for you: mainly Jarkko fixed up a few things in the designware driver regarding the new slave mode. But Ulf also fixed a long-standing and now agreed suspend problem. Plus, some simple stuff which nonetheless needs fixing" * 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux: i2c: designware: Fix runtime PM for I2C slave mode i2c: designware: Remove needless pm_runtime_put_noidle() call i2c: aspeed: fixed potential null pointer dereference i2c: simtec: use release_mem_region instead of release_resource i2c: core: Make comment about I2C table requirement to reflect the code i2c: designware: Fix standard mode speed when configuring the slave mode i2c: designware: Fix oops from i2c_dw_irq_handler_slave i2c: designware: Fix system suspend
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Christoph Hellwig authored
irq_create_affinity_masks() can return NULL on non-SMP systems, when there are not enough "free" vectors available to spread, or if memory allocation for the CPU masks fails. Only the allocation failure is of interest, and even then the system will work just fine except for non-optimally spread vectors. Thus remove the warnings. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: David S. Miller <davem@davemloft.net>
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git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmcLinus Torvalds authored
Pull MMC fix from Ulf Hansson: "MMC core: don't return error code R1_OUT_OF_RANGE for open-ending mode" * tag 'mmc-v4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc: mmc: block: prevent propagating R1_OUT_OF_RANGE for open-ending mode
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/soundLinus Torvalds authored
Pull sound fixes from Takashi Iwai: "We're keeping in a good shape, this batch contains just a few small fixes (a regression fix for ASoC rt5677 codec, NULL dereference and error-path fixes in firewire, and a corner-case ioctl error fix for user TLV), as well as usual quirks for USB-audio and HD-audio" * tag 'sound-4.13-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: ASoC: rt5677: Reintroduce I2C device IDs ALSA: hda - Add stereo mic quirk for Lenovo G50-70 (17aa:3978) ALSA: core: Fix unexpected error at replacing user TLV ALSA: usb-audio: Add delay quirk for H650e/Jabra 550a USB headsets ALSA: firewire-motu: destroy stream data surely at failure of card initialization ALSA: firewire: fix NULL pointer dereference when releasing uninitialized data of iso-resource
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git://git.infradead.org/users/vkoul/slave-dmaLinus Torvalds authored
Pull dmaengine fix from Vinod Koul: "A single fix for tegra210-adma driver to check of_irq_get() error" * tag 'dmaengine-fix-4.13-rc7' of git://git.infradead.org/users/vkoul/slave-dma: dmaengine: tegra210-adma: fix of_irq_get() error check
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git://people.freedesktop.org/~airlied/linuxLinus Torvalds authored
Pull drm fixes from Dave Airlie: "Fixes for rc7, nothing too crazy, some core, i915, and sunxi fixes, Intel CI has been responsible for some of these fixes being required" * tag 'drm-fixes-for-v4.13-rc7' of git://people.freedesktop.org/~airlied/linux: drm/i915/gvt: Fix the kernel null pointer error drm: Release driver tracking before making the object available again drm/i915: Clear lost context-switch interrupts across reset drm/i915/bxt: use NULL for GPIO connection ID drm/i915/cnl: Fix LSPCON support. drm/i915/vbt: ignore extraneous child devices for a port drm/i915: Initialize 'data' in intel_dsi_dcs_backlight.c drm/atomic: If the atomic check fails, return its value first drm/atomic: Handle -EDEADLK with out-fences correctly drm: Fix framebuffer leak drm/imx: ipuv3-plane: fix YUV framebuffer scanout on the base plane gpu: ipu-v3: add DRM dependency drm/rockchip: Fix suspend crash when drm is not bound drm/sun4i: Implement drm_driver lastclose to restore fbdev console
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Pavel Tatashin authored
In recently introduced memblock_discard() there is a reversed logic bug. Memory is freed of static array instead of dynamically allocated one. Link: http://lkml.kernel.org/r/1503511441-95478-2-git-send-email-pasha.tatashin@oracle.com Fixes: 3010f876 ("mm: discard memblock data later") Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com> Reported-by: Woody Suwalski <terraluna977@gmail.com> Tested-by: Woody Suwalski <terraluna977@gmail.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Eric Biggers authored
Commit 7c051267 ("mm, fork: make dup_mmap wait for mmap_sem for write killable") made it possible to kill a forking task while it is waiting to acquire its ->mmap_sem for write, in dup_mmap(). However, it was overlooked that this introduced an new error path before a reference is taken on the mm_struct's ->exe_file. Since the ->exe_file of the new mm_struct was already set to the old ->exe_file by the memcpy() in dup_mm(), it was possible for the mmput() in the error path of dup_mm() to drop a reference to ->exe_file which was never taken. This caused the struct file to later be freed prematurely. Fix it by updating mm_init() to NULL out the ->exe_file, in the same place it clears other things like the list of mmaps. This bug was found by syzkaller. It can be reproduced using the following C program: #define _GNU_SOURCE #include <pthread.h> #include <stdlib.h> #include <sys/mman.h> #include <sys/syscall.h> #include <sys/wait.h> #include <unistd.h> static void *mmap_thread(void *_arg) { for (;;) { mmap(NULL, 0x1000000, PROT_READ, MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); } } static void *fork_thread(void *_arg) { usleep(rand() % 10000); fork(); } int main(void) { fork(); fork(); fork(); for (;;) { if (fork() == 0) { pthread_t t; pthread_create(&t, NULL, mmap_thread, NULL); pthread_create(&t, NULL, fork_thread, NULL); usleep(rand() % 10000); syscall(__NR_exit_group, 0); } wait(NULL); } } No special kernel config options are needed. It usually causes a NULL pointer dereference in __remove_shared_vm_struct() during exit, or in dup_mmap() (which is usually inlined into copy_process()) during fork. Both are due to a vm_area_struct's ->vm_file being used after it's already been freed. Google Bug Id: 64772007 Link: http://lkml.kernel.org/r/20170823211408.31198-1-ebiggers3@gmail.com Fixes: 7c051267 ("mm, fork: make dup_mmap wait for mmap_sem for write killable") Signed-off-by: Eric Biggers <ebiggers@google.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: <stable@vger.kernel.org> [v4.7+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Eric Biggers authored
If madvise(..., MADV_FREE) split a transparent hugepage, it called put_page() before unlock_page(). This was wrong because put_page() can free the page, e.g. if a concurrent madvise(..., MADV_DONTNEED) has removed it from the memory mapping. put_page() then rightfully complained about freeing a locked page. Fix this by moving the unlock_page() before put_page(). This bug was found by syzkaller, which encountered the following splat: BUG: Bad page state in process syzkaller412798 pfn:1bd800 page:ffffea0006f60000 count:0 mapcount:0 mapping: (null) index:0x20a00 flags: 0x200000000040019(locked|uptodate|dirty|swapbacked) raw: 0200000000040019 0000000000000000 0000000000020a00 00000000ffffffff raw: ffffea0006f60020 ffffea0006f60020 0000000000000000 0000000000000000 page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set bad because of flags: 0x1(locked) Modules linked in: CPU: 1 PID: 3037 Comm: syzkaller412798 Not tainted 4.13.0-rc5+ #35 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 bad_page+0x230/0x2b0 mm/page_alloc.c:565 free_pages_check_bad+0x1f0/0x2e0 mm/page_alloc.c:943 free_pages_check mm/page_alloc.c:952 [inline] free_pages_prepare mm/page_alloc.c:1043 [inline] free_pcp_prepare mm/page_alloc.c:1068 [inline] free_hot_cold_page+0x8cf/0x12b0 mm/page_alloc.c:2584 __put_single_page mm/swap.c:79 [inline] __put_page+0xfb/0x160 mm/swap.c:113 put_page include/linux/mm.h:814 [inline] madvise_free_pte_range+0x137a/0x1ec0 mm/madvise.c:371 walk_pmd_range mm/pagewalk.c:50 [inline] walk_pud_range mm/pagewalk.c:108 [inline] walk_p4d_range mm/pagewalk.c:134 [inline] walk_pgd_range mm/pagewalk.c:160 [inline] __walk_page_range+0xc3a/0x1450 mm/pagewalk.c:249 walk_page_range+0x200/0x470 mm/pagewalk.c:326 madvise_free_page_range.isra.9+0x17d/0x230 mm/madvise.c:444 madvise_free_single_vma+0x353/0x580 mm/madvise.c:471 madvise_dontneed_free mm/madvise.c:555 [inline] madvise_vma mm/madvise.c:664 [inline] SYSC_madvise mm/madvise.c:832 [inline] SyS_madvise+0x7d3/0x13c0 mm/madvise.c:760 entry_SYSCALL_64_fastpath+0x1f/0xbe Here is a C reproducer: #define _GNU_SOURCE #include <pthread.h> #include <sys/mman.h> #include <unistd.h> #define MADV_FREE 8 #define PAGE_SIZE 4096 static void *mapping; static const size_t mapping_size = 0x1000000; static void *madvise_thrproc(void *arg) { madvise(mapping, mapping_size, (long)arg); } int main(void) { pthread_t t[2]; for (;;) { mapping = mmap(NULL, mapping_size, PROT_WRITE, MAP_POPULATE|MAP_ANONYMOUS|MAP_PRIVATE, -1, 0); munmap(mapping + mapping_size / 2, PAGE_SIZE); pthread_create(&t[0], 0, madvise_thrproc, (void*)MADV_DONTNEED); pthread_create(&t[1], 0, madvise_thrproc, (void*)MADV_FREE); pthread_join(t[0], NULL); pthread_join(t[1], NULL); munmap(mapping, mapping_size); } } Note: to see the splat, CONFIG_TRANSPARENT_HUGEPAGE=y and CONFIG_DEBUG_VM=y are needed. Google Bug Id: 64696096 Link: http://lkml.kernel.org/r/20170823205235.132061-1-ebiggers3@gmail.com Fixes: 854e9ed0 ("mm: support madvise(MADV_FREE)") Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> [v4.5+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ross Zwisler authored
In DAX there are two separate places where the 2MiB range of a PMD is defined. The first is in the page tables, where a PMD mapping inserted for a given address spans from (vmf->address & PMD_MASK) to ((vmf->address & PMD_MASK) + PMD_SIZE - 1). That is, from the 2MiB boundary below the address to the 2MiB boundary above the address. So, for example, a fault at address 3MiB (0x30 0000) falls within the PMD that ranges from 2MiB (0x20 0000) to 4MiB (0x40 0000). The second PMD range is in the mapping->page_tree, where a given file offset is covered by a radix tree entry that spans from one 2MiB aligned file offset to another 2MiB aligned file offset. So, for example, the file offset for 3MiB (pgoff 768) falls within the PMD range for the order 9 radix tree entry that ranges from 2MiB (pgoff 512) to 4MiB (pgoff 1024). This system works so long as the addresses and file offsets for a given mapping both have the same offsets relative to the start of each PMD. Consider the case where the starting address for a given file isn't 2MiB aligned - say our faulting address is 3 MiB (0x30 0000), but that corresponds to the beginning of our file (pgoff 0). Now all the PMDs in the mapping are misaligned so that the 2MiB range defined in the page tables never matches up with the 2MiB range defined in the radix tree. The current code notices this case for DAX faults to storage with the following test in dax_pmd_insert_mapping(): if (pfn_t_to_pfn(pfn) & PG_PMD_COLOUR) goto unlock_fallback; This test makes sure that the pfn we get from the driver is 2MiB aligned, and relies on the assumption that the 2MiB alignment of the pfn we get back from the driver matches the 2MiB alignment of the faulting address. However, faults to holes were not checked and we could hit the problem described above. This was reported in response to the NVML nvml/src/test/pmempool_sync TEST5: $ cd nvml/src/test/pmempool_sync $ make TEST5 You can grab NVML here: https://github.com/pmem/nvml/ The dmesg warning you see when you hit this error is: WARNING: CPU: 13 PID: 2900 at fs/dax.c:641 dax_insert_mapping_entry+0x2df/0x310 Where we notice in dax_insert_mapping_entry() that the radix tree entry we are about to replace doesn't match the locked entry that we had previously inserted into the tree. This happens because the initial insertion was done in grab_mapping_entry() using a pgoff calculated from the faulting address (vmf->address), and the replacement in dax_pmd_load_hole() => dax_insert_mapping_entry() is done using vmf->pgoff. In our failure case those two page offsets (one calculated from vmf->address, one using vmf->pgoff) point to different order 9 radix tree entries. This failure case can result in a deadlock because the radix tree unlock also happens on the pgoff calculated from vmf->address. This means that the locked radix tree entry that we swapped in to the tree in dax_insert_mapping_entry() using vmf->pgoff is never unlocked, so all future faults to that 2MiB range will block forever. Fix this by validating that the faulting address's PMD offset matches the PMD offset from the start of the file. This check is done at the very beginning of the fault and covers faults that would have mapped to storage as well as faults to holes. I left the COLOUR check in dax_pmd_insert_mapping() in place in case we ever hit the insanity condition where the alignment of the pfn we get from the driver doesn't match the alignment of the userspace address. Link: http://lkml.kernel.org/r/20170822222436.18926-1-ross.zwisler@linux.intel.comSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reported-by: "Slusarz, Marcin" <marcin.slusarz@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Matthew Wilcox <mawilcox@microsoft.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Kirill A. Shutemov authored
/sys/kernel/mm/transparent_hugepage/shmem_enabled controls if we want to allocate huge pages when allocate pages for private in-kernel shmem mount. Unfortunately, as Dan noticed, I've screwed it up and the only way to make kernel allocate huge page for the mount is to use "force" there. All other values will be effectively ignored. Link: http://lkml.kernel.org/r/20170822144254.66431-1-kirill.shutemov@linux.intel.com Fixes: 5a6e75f8 ("shmem: prepare huge= mount option and sysfs knob") Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: stable <stable@vger.kernel.org> [4.8+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Chen Yu authored
There is a problem that when counting the pages for creating the hibernation snapshot will take significant amount of time, especially on system with large memory. Since the counting job is performed with irq disabled, this might lead to NMI lockup. The following warning were found on a system with 1.5TB DRAM: Freezing user space processes ... (elapsed 0.002 seconds) done. OOM killer disabled. PM: Preallocating image memory... NMI watchdog: Watchdog detected hard LOCKUP on cpu 27 CPU: 27 PID: 3128 Comm: systemd-sleep Not tainted 4.13.0-0.rc2.git0.1.fc27.x86_64 #1 task: ffff9f01971ac000 task.stack: ffffb1a3f325c000 RIP: 0010:memory_bm_find_bit+0xf4/0x100 Call Trace: swsusp_set_page_free+0x2b/0x30 mark_free_pages+0x147/0x1c0 count_data_pages+0x41/0xa0 hibernate_preallocate_memory+0x80/0x450 hibernation_snapshot+0x58/0x410 hibernate+0x17c/0x310 state_store+0xdf/0xf0 kobj_attr_store+0xf/0x20 sysfs_kf_write+0x37/0x40 kernfs_fop_write+0x11c/0x1a0 __vfs_write+0x37/0x170 vfs_write+0xb1/0x1a0 SyS_write+0x55/0xc0 entry_SYSCALL_64_fastpath+0x1a/0xa5 ... done (allocated 6590003 pages) PM: Allocated 26360012 kbytes in 19.89 seconds (1325.28 MB/s) It has taken nearly 20 seconds(2.10GHz CPU) thus the NMI lockup was triggered. In case the timeout of the NMI watch dog has been set to 1 second, a safe interval should be 6590003/20 = 320k pages in theory. However there might also be some platforms running at a lower frequency, so feed the watchdog every 100k pages. [yu.c.chen@intel.com: simplification] Link: http://lkml.kernel.org/r/1503460079-29721-1-git-send-email-yu.c.chen@intel.com [yu.c.chen@intel.com: use interval of 128k instead of 100k to avoid modulus] Link: http://lkml.kernel.org/r/1503328098-5120-1-git-send-email-yu.c.chen@intel.comSigned-off-by: Chen Yu <yu.c.chen@intel.com> Reported-by: Jan Filipcewicz <jan.filipcewicz@intel.com> Suggested-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Michal Hocko <mhocko@suse.com> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Len Brown <lenb@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Christoph Hellwig authored
Commit 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for virtqueues"") removed the adjustment of the pre_vectors for the virtio MSI-X vector allocation which was added in commit fb5e31d9 ("virtio: allow drivers to request IRQ affinity when creating VQs"). This will lead to an incorrect assignment of MSI-X vectors, and potential deadlocks when offlining cpus. Signed-off-by: Christoph Hellwig <hch@lst.de> Fixes: 0b0f9dc5 ("Revert "virtio_pci: use shared interrupts for virtqueues") Reported-by: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Stefan Hajnoczi authored
The message printed on disk resize is incorrect. The following is printed when resizing to 2 GiB: $ truncate -s 1G test.img $ qemu -device virtio-blk-pci,logical_block_size=4096,... (qemu) block_resize drive1 2G virtio_blk virtio0: new size: 4194304 4096-byte logical blocks (17.2 GB/16.0 GiB) The virtio_blk capacity config field is in 512-byte sector units regardless of logical_block_size as per the VIRTIO specification. Therefore the message should read: virtio_blk virtio0: new size: 524288 4096-byte logical blocks (2.15 GB/2.0 GiB) Note that this only affects the printed message. Thankfully the actual block device has the correct size because the block layer expects capacity in sectors. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Bart Van Assche authored
The symbolic constants QUEUE_FLAG_SCSI_PASSTHROUGH, QUEUE_FLAG_QUIESCED and REQ_NOWAIT are missing from blk-mq-debugfs.c. Add these to blk-mq-debugfs.c such that these appear as names in debugfs instead of as numbers. Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Paul Mackerras authored
Nixiaoming pointed out that there is a memory leak in kvm_vm_ioctl_create_spapr_tce() if the call to anon_inode_getfd() fails; the memory allocated for the kvmppc_spapr_tce_table struct is not freed, and nor are the pages allocated for the iommu tables. In addition, we have already incremented the process's count of locked memory pages, and this doesn't get restored on error. David Hildenbrand pointed out that there is a race in that the function checks early on that there is not already an entry in the stt->iommu_tables list with the same LIOBN, but an entry with the same LIOBN could get added between then and when the new entry is added to the list. This fixes all three problems. To simplify things, we now call anon_inode_getfd() before placing the new entry in the list. The check for an existing entry is done while holding the kvm->lock mutex, immediately before adding the new entry to the list. Finally, on failure we now call kvmppc_account_memlimit to decrement the process's count of locked memory pages. Reported-by: Nixiaoming <nixiaoming@huawei.com> Reported-by: David Hildenbrand <david@redhat.com> Signed-off-by: Paul Mackerras <paulus@ozlabs.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Mark Rutland authored
Regardless of which events form a group, it does not make sense for the events to target different tasks and/or CPUs, as this leaves the group inconsistent and impossible to schedule. The core perf code assumes that these are consistent across (successfully intialised) groups. Core perf code only verifies this when moving SW events into a HW context. Thus, we can violate this requirement for pure SW groups and pure HW groups, unless the relevant PMU driver happens to perform this verification itself. These mismatched groups subsequently wreak havoc elsewhere. For example, we handle watchpoints as SW events, and reserve watchpoint HW on a per-CPU basis at pmu::event_init() time to ensure that any event that is initialised is guaranteed to have a slot at pmu::add() time. However, the core code only checks the group leader's cpu filter (via event_filter_match()), and can thus install follower events onto CPUs violating thier (mismatched) CPU filters, potentially installing them into a CPU without sufficient reserved slots. This can be triggered with the below test case, resulting in warnings from arch backends. #define _GNU_SOURCE #include <linux/hw_breakpoint.h> #include <linux/perf_event.h> #include <sched.h> #include <stdio.h> #include <sys/prctl.h> #include <sys/syscall.h> #include <unistd.h> static int perf_event_open(struct perf_event_attr *attr, pid_t pid, int cpu, int group_fd, unsigned long flags) { return syscall(__NR_perf_event_open, attr, pid, cpu, group_fd, flags); } char watched_char; struct perf_event_attr wp_attr = { .type = PERF_TYPE_BREAKPOINT, .bp_type = HW_BREAKPOINT_RW, .bp_addr = (unsigned long)&watched_char, .bp_len = 1, .size = sizeof(wp_attr), }; int main(int argc, char *argv[]) { int leader, ret; cpu_set_t cpus; /* * Force use of CPU0 to ensure our CPU0-bound events get scheduled. */ CPU_ZERO(&cpus); CPU_SET(0, &cpus); ret = sched_setaffinity(0, sizeof(cpus), &cpus); if (ret) { printf("Unable to set cpu affinity\n"); return 1; } /* open leader event, bound to this task, CPU0 only */ leader = perf_event_open(&wp_attr, 0, 0, -1, 0); if (leader < 0) { printf("Couldn't open leader: %d\n", leader); return 1; } /* * Open a follower event that is bound to the same task, but a * different CPU. This means that the group should never be possible to * schedule. */ ret = perf_event_open(&wp_attr, 0, 1, leader, 0); if (ret < 0) { printf("Couldn't open mismatched follower: %d\n", ret); return 1; } else { printf("Opened leader/follower with mismastched CPUs\n"); } /* * Open as many independent events as we can, all bound to the same * task, CPU0 only. */ do { ret = perf_event_open(&wp_attr, 0, 0, -1, 0); } while (ret >= 0); /* * Force enable/disble all events to trigger the erronoeous * installation of the follower event. */ printf("Opened all events. Toggling..\n"); for (;;) { prctl(PR_TASK_PERF_EVENTS_DISABLE, 0, 0, 0, 0); prctl(PR_TASK_PERF_EVENTS_ENABLE, 0, 0, 0, 0); } return 0; } Fix this by validating this requirement regardless of whether we're moving events. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Zhou Chengming <zhouchengming1@huawei.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1498142498-15758-1-git-send-email-mark.rutland@arm.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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Eric Biggers authored
The following commit: 39a0526f ("x86/mm: Factor out LDT init from context init") renamed init_new_context() to init_new_context_ldt() and added a new init_new_context() which calls init_new_context_ldt(). However, the error code of init_new_context_ldt() was ignored. Consequently, if a memory allocation in alloc_ldt_struct() failed during a fork(), the ->context.ldt of the new task remained the same as that of the old task (due to the memcpy() in dup_mm()). ldt_struct's are not intended to be shared, so a use-after-free occurred after one task exited. Fix the bug by making init_new_context() pass through the error code of init_new_context_ldt(). This bug was found by syzkaller, which encountered the following splat: BUG: KASAN: use-after-free in free_ldt_struct.part.2+0x10a/0x150 arch/x86/kernel/ldt.c:116 Read of size 4 at addr ffff88006d2cb7c8 by task kworker/u9:0/3710 CPU: 1 PID: 3710 Comm: kworker/u9:0 Not tainted 4.13.0-rc4-next-20170811 #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:16 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:52 print_address_description+0x73/0x250 mm/kasan/report.c:252 kasan_report_error mm/kasan/report.c:351 [inline] kasan_report+0x24e/0x340 mm/kasan/report.c:409 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:429 free_ldt_struct.part.2+0x10a/0x150 arch/x86/kernel/ldt.c:116 free_ldt_struct arch/x86/kernel/ldt.c:173 [inline] destroy_context_ldt+0x60/0x80 arch/x86/kernel/ldt.c:171 destroy_context arch/x86/include/asm/mmu_context.h:157 [inline] __mmdrop+0xe9/0x530 kernel/fork.c:889 mmdrop include/linux/sched/mm.h:42 [inline] exec_mmap fs/exec.c:1061 [inline] flush_old_exec+0x173c/0x1ff0 fs/exec.c:1291 load_elf_binary+0x81f/0x4ba0 fs/binfmt_elf.c:855 search_binary_handler+0x142/0x6b0 fs/exec.c:1652 exec_binprm fs/exec.c:1694 [inline] do_execveat_common.isra.33+0x1746/0x22e0 fs/exec.c:1816 do_execve+0x31/0x40 fs/exec.c:1860 call_usermodehelper_exec_async+0x457/0x8f0 kernel/umh.c:100 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431 Allocated by task 3700: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3627 kmalloc include/linux/slab.h:493 [inline] alloc_ldt_struct+0x52/0x140 arch/x86/kernel/ldt.c:67 write_ldt+0x7b7/0xab0 arch/x86/kernel/ldt.c:277 sys_modify_ldt+0x1ef/0x240 arch/x86/kernel/ldt.c:307 entry_SYSCALL_64_fastpath+0x1f/0xbe Freed by task 3700: save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59 save_stack+0x43/0xd0 mm/kasan/kasan.c:447 set_track mm/kasan/kasan.c:459 [inline] kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524 __cache_free mm/slab.c:3503 [inline] kfree+0xca/0x250 mm/slab.c:3820 free_ldt_struct.part.2+0xdd/0x150 arch/x86/kernel/ldt.c:121 free_ldt_struct arch/x86/kernel/ldt.c:173 [inline] destroy_context_ldt+0x60/0x80 arch/x86/kernel/ldt.c:171 destroy_context arch/x86/include/asm/mmu_context.h:157 [inline] __mmdrop+0xe9/0x530 kernel/fork.c:889 mmdrop include/linux/sched/mm.h:42 [inline] __mmput kernel/fork.c:916 [inline] mmput+0x541/0x6e0 kernel/fork.c:927 copy_process.part.36+0x22e1/0x4af0 kernel/fork.c:1931 copy_process kernel/fork.c:1546 [inline] _do_fork+0x1ef/0xfb0 kernel/fork.c:2025 SYSC_clone kernel/fork.c:2135 [inline] SyS_clone+0x37/0x50 kernel/fork.c:2129 do_syscall_64+0x26c/0x8c0 arch/x86/entry/common.c:287 return_from_SYSCALL_64+0x0/0x7a Here is a C reproducer: #include <asm/ldt.h> #include <pthread.h> #include <signal.h> #include <stdlib.h> #include <sys/syscall.h> #include <sys/wait.h> #include <unistd.h> static void *fork_thread(void *_arg) { fork(); } int main(void) { struct user_desc desc = { .entry_number = 8191 }; syscall(__NR_modify_ldt, 1, &desc, sizeof(desc)); for (;;) { if (fork() == 0) { pthread_t t; srand(getpid()); pthread_create(&t, NULL, fork_thread, NULL); usleep(rand() % 10000); syscall(__NR_exit_group, 0); } wait(NULL); } } Note: the reproducer takes advantage of the fact that alloc_ldt_struct() may use vmalloc() to allocate a large ->entries array, and after commit: 5d17a73a ("vmalloc: back off when the current task is killed") it is possible for userspace to fail a task's vmalloc() by sending a fatal signal, e.g. via exit_group(). It would be more difficult to reproduce this bug on kernels without that commit. This bug only affected kernels with CONFIG_MODIFY_LDT_SYSCALL=y. Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: <stable@vger.kernel.org> [v4.6+] Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mm@kvack.org Fixes: 39a0526f ("x86/mm: Factor out LDT init from context init") Link: http://lkml.kernel.org/r/20170824175029.76040-1-ebiggers3@gmail.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
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