- 12 Jul, 2016 16 commits
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Shaokun Zhang authored
[ Upstream commit 20c27a42 ] __sync_icache_dcache unconditionally skips the cache maintenance for anonymous pages, under the assumption that flushing is only required in the presence of D-side aliases [see 7249b79f ("arm64: Do not flush the D-cache for anonymous pages")]. Unfortunately, this breaks migration of anonymous pages holding self-modifying code, where userspace cannot be reasonably expected to reissue maintenance instructions in response to a migration. This patch fixes the problem by removing the broken page_mapping(page) check from the cache syncing code, otherwise we may end up fetching and executing stale instructions from the PoU. Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: <stable@vger.kernel.org> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Steven Rostedt (Red Hat) authored
[ Upstream commit 70c8217a ] If a task uses a non constant string for the format parameter in trace_printk(), then the trace_printk_fmt variable is set to NULL. This variable is then saved in the __trace_printk_fmt section. The function hold_module_trace_bprintk_format() checks to see if duplicate formats are used by modules, and reuses them if so (saves them to the list if it is new). But this function calls lookup_format() that does a strcmp() to the value (which is now NULL) and can cause a kernel oops. This wasn't an issue till 3debb0a9 ("tracing: Fix trace_printk() to print when not using bprintk()") which added "__used" to the trace_printk_fmt variable, and before that, the kernel simply optimized it out (no NULL value was saved). The fix is simply to handle the NULL pointer in lookup_format() and have the caller ignore the value if it was NULL. Link: http://lkml.kernel.org/r/1464769870-18344-1-git-send-email-zhengjun.xing@intel.comReported-by: xingzhen <zhengjun.xing@intel.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Fixes: 3debb0a9 ("tracing: Fix trace_printk() to print when not using bprintk()") Cc: stable@vger.kernel.org # v3.5+ Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Wolfgang Grandegger authored
[ Upstream commit 43200a44 ] At high bus load it could happen that "at91_poll()" enters with all RX message boxes filled up. If then at the end the "quota" is exceeded as well, "rx_next" will not be reset to the first RX mailbox and hence the interrupts remain disabled. Signed-off-by: Wolfgang Grandegger <wg@grandegger.com> Tested-by: Amr Bekhit <amrbekhit@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Thor Thayer authored
[ Upstream commit 427460c8 ] When testing CAN write floods on Altera's CycloneV, the first 2 bytes are sometimes 0x00, 0x00 or corrupted instead of the values sent. Also observed bytes 4 & 5 were corrupted in some cases. The D_CAN Data registers are 32 bits and changing from 16 bit writes to 32 bit writes fixes the problem. Testing performed on Altera CycloneV (D_CAN). Requesting tests on other C_CAN & D_CAN platforms. Reported-by: Richard Andrysek <richard.andrysek@gomtec.de> Signed-off-by: Thor Thayer <tthayer@opensource.altera.com> Cc: <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Jason Gunthorpe authored
[ Upstream commit 8c5122e4 ] When this code was reworked for IBoE support the order of assignments for the sl_tclass_flowlabel got flipped around resulting in TClass & FlowLabel being permanently set to 0 in the packet headers. This breaks IB routers that rely on these headers, but only affects kernel users - libmlx4 does this properly for user space. Cc: stable@vger.kernel.org Fixes: fa417f7b ("IB/mlx4: Add support for IBoE") Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Doug Ledford <dledford@redhat.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Jeff Mahoney authored
[ Upstream commit 64c12921 ] The test for !trans->blocks_used in btrfs_abort_transaction is insufficient to determine whether it's safe to drop the transaction handle on the floor. btrfs_cow_block, informed by should_cow_block, can return blocks that have already been CoW'd in the current transaction. trans->blocks_used is only incremented for new block allocations. If an operation overlaps the blocks in the current transaction entirely and must abort the transaction, we'll happily let it clean up the trans handle even though it may have modified the blocks and will commit an incomplete operation. In the long-term, I'd like to do closer tracking of when the fs is actually modified so we can still recover as gracefully as possible, but that approach will need some discussion. In the short term, since this is the only code using trans->blocks_used, let's just switch it to a bool indicating whether any blocks were used and set it when should_cow_block returns false. Cc: stable@vger.kernel.org # 3.4+ Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Filipe Manana authored
[ Upstream commit c92f6be3 ] If the transaction handle doesn't have used blocks but has created new block groups make sure we turn the fs into readonly mode too. This is because the new block groups didn't get all their metadata persisted into the chunk and device trees, and therefore if a subsequent transaction starts, allocates space from the new block groups, writes data or metadata into that space, commits successfully and then after we unmount and mount the filesystem again, the same space can be allocated again for a new block group, resulting in file data or metadata corruption. Example where we don't abort the transaction when we fail to finish the chunk allocation (add items to the chunk and device trees) and later a future transaction where the block group is removed fails because it can't find the chunk item in the chunk tree: [25230.404300] WARNING: CPU: 0 PID: 7721 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x50/0xfc [btrfs]() [25230.404301] BTRFS: Transaction aborted (error -28) [25230.404302] Modules linked in: btrfs dm_flakey nls_utf8 fuse xor raid6_pq ntfs vfat msdos fat xfs crc32c_generic libcrc32c ext3 jbd ext2 dm_mod nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc loop psmouse i2c_piix4 i2ccore parport_pc parport processor button pcspkr serio_raw thermal_sys evdev microcode ext4 crc16 jbd2 mbcache sr_mod cdrom ata_generic sg sd_mod crc_t10dif crct10dif_generic crct10dif_common virtio_scsi floppy e1000 ata_piix libata virtio_pci virtio_ring scsi_mod virtio [last unloaded: btrfs] [25230.404325] CPU: 0 PID: 7721 Comm: xfs_io Not tainted 3.17.0-rc5-btrfs-next-1+ #1 [25230.404326] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [25230.404328] 0000000000000000 ffff88004581bb08 ffffffff813e7a13 ffff88004581bb50 [25230.404330] ffff88004581bb40 ffffffff810423aa ffffffffa049386a 00000000ffffffe4 [25230.404332] ffffffffa05214c0 000000000000240c ffff88010fc8f800 ffff88004581bba8 [25230.404334] Call Trace: [25230.404338] [<ffffffff813e7a13>] dump_stack+0x45/0x56 [25230.404342] [<ffffffff810423aa>] warn_slowpath_common+0x7f/0x98 [25230.404351] [<ffffffffa049386a>] ? __btrfs_abort_transaction+0x50/0xfc [btrfs] [25230.404353] [<ffffffff8104240b>] warn_slowpath_fmt+0x48/0x50 [25230.404362] [<ffffffffa049386a>] __btrfs_abort_transaction+0x50/0xfc [btrfs] [25230.404374] [<ffffffffa04a8c43>] btrfs_create_pending_block_groups+0x10c/0x135 [btrfs] [25230.404387] [<ffffffffa04b77fd>] __btrfs_end_transaction+0x7e/0x2de [btrfs] [25230.404398] [<ffffffffa04b7a6d>] btrfs_end_transaction+0x10/0x12 [btrfs] [25230.404408] [<ffffffffa04a3d64>] btrfs_check_data_free_space+0x111/0x1f0 [btrfs] [25230.404421] [<ffffffffa04c53bd>] __btrfs_buffered_write+0x160/0x48d [btrfs] [25230.404425] [<ffffffff811a9268>] ? cap_inode_need_killpriv+0x2d/0x37 [25230.404429] [<ffffffff810f6501>] ? get_page+0x1a/0x2b [25230.404441] [<ffffffffa04c7c95>] btrfs_file_write_iter+0x321/0x42f [btrfs] [25230.404443] [<ffffffff8110f5d9>] ? handle_mm_fault+0x7f3/0x846 [25230.404446] [<ffffffff813e98c5>] ? mutex_unlock+0x16/0x18 [25230.404449] [<ffffffff81138d68>] new_sync_write+0x7c/0xa0 [25230.404450] [<ffffffff81139401>] vfs_write+0xb0/0x112 [25230.404452] [<ffffffff81139c9d>] SyS_pwrite64+0x66/0x84 [25230.404454] [<ffffffff813ebf52>] system_call_fastpath+0x16/0x1b [25230.404455] ---[ end trace 5aa5684fdf47ab38 ]--- [25230.404458] BTRFS warning (device sdc): btrfs_create_pending_block_groups:9228: Aborting unused transaction(No space left). [25288.084814] BTRFS: error (device sdc) in btrfs_free_chunk:2509: errno=-2 No such entry (Failed lookup while freeing chunk.) Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Dan Carpenter authored
[ Upstream commit 38327424 ] If __key_link_begin() failed then "edit" would be uninitialized. I've added a check to fix that. This allows a random user to crash the kernel, though it's quite difficult to achieve. There are three ways it can be done as the user would have to cause an error to occur in __key_link(): (1) Cause the kernel to run out of memory. In practice, this is difficult to achieve without ENOMEM cropping up elsewhere and aborting the attempt. (2) Revoke the destination keyring between the keyring ID being looked up and it being tested for revocation. In practice, this is difficult to time correctly because the KEYCTL_REJECT function can only be used from the request-key upcall process. Further, users can only make use of what's in /sbin/request-key.conf, though this does including a rejection debugging test - which means that the destination keyring has to be the caller's session keyring in practice. (3) Have just enough key quota available to create a key, a new session keyring for the upcall and a link in the session keyring, but not then sufficient quota to create a link in the nominated destination keyring so that it fails with EDQUOT. The bug can be triggered using option (3) above using something like the following: echo 80 >/proc/sys/kernel/keys/root_maxbytes keyctl request2 user debug:fred negate @t The above sets the quota to something much lower (80) to make the bug easier to trigger, but this is dependent on the system. Note also that the name of the keyring created contains a random number that may be between 1 and 10 characters in size, so may throw the test off by changing the amount of quota used. Assuming the failure occurs, something like the following will be seen: kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b68h ------------[ cut here ]------------ kernel BUG at ../mm/slab.c:2821! ... RIP: 0010:[<ffffffff811600f9>] kfree_debugcheck+0x20/0x25 RSP: 0018:ffff8804014a7de8 EFLAGS: 00010092 RAX: 0000000000000034 RBX: 6b6b6b6b6b6b6b68 RCX: 0000000000000000 RDX: 0000000000040001 RSI: 00000000000000f6 RDI: 0000000000000300 RBP: ffff8804014a7df0 R08: 0000000000000001 R09: 0000000000000000 R10: ffff8804014a7e68 R11: 0000000000000054 R12: 0000000000000202 R13: ffffffff81318a66 R14: 0000000000000000 R15: 0000000000000001 ... Call Trace: kfree+0xde/0x1bc assoc_array_cancel_edit+0x1f/0x36 __key_link_end+0x55/0x63 key_reject_and_link+0x124/0x155 keyctl_reject_key+0xb6/0xe0 keyctl_negate_key+0x10/0x12 SyS_keyctl+0x9f/0xe7 do_syscall_64+0x63/0x13a entry_SYSCALL64_slow_path+0x25/0x25 Fixes: f70e2e06 ('KEYS: Do preallocation for __key_link()') Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: David Howells <dhowells@redhat.com> cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Xiubo Li authored
[ Upstream commit caf1ff26 ] These days, we experienced one guest crash with 8 cores and 3 disks, with qemu error logs as bellow: qemu-system-x86_64: /build/qemu-2.0.0/kvm-all.c:984: kvm_irqchip_commit_routes: Assertion `ret == 0' failed. And then we found one patch(bdf026317d) in qemu tree, which said could fix this bug. Execute the following script will reproduce the BUG quickly: irq_affinity.sh ======================================================================== vda_irq_num=25 vdb_irq_num=27 while [ 1 ] do for irq in {1,2,4,8,10,20,40,80} do echo $irq > /proc/irq/$vda_irq_num/smp_affinity echo $irq > /proc/irq/$vdb_irq_num/smp_affinity dd if=/dev/vda of=/dev/zero bs=4K count=100 iflag=direct dd if=/dev/vdb of=/dev/zero bs=4K count=100 iflag=direct done done ======================================================================== The following qemu log is added in the qemu code and is displayed when this bug reproduced: kvm_irqchip_commit_routes: max gsi: 1008, nr_allocated_irq_routes: 1024, irq_routes->nr: 1024, gsi_count: 1024. That's to say when irq_routes->nr == 1024, there are 1024 routing entries, but in the kernel code when routes->nr >= 1024, will just return -EINVAL; The nr is the number of the routing entries which is in of [1 ~ KVM_MAX_IRQ_ROUTES], not the index in [0 ~ KVM_MAX_IRQ_ROUTES - 1]. This patch fix the BUG above. Cc: stable@vger.kernel.org Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com> Signed-off-by: Wei Tang <tangwei@cmss.chinamobile.com> Signed-off-by: Zhang Zhuoyu <zhangzhuoyu@cmss.chinamobile.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Jiri Slaby authored
[ Upstream commit 7e1b1fc4 ] Modules which register drivers via standard path (driver_register) in parallel can cause a warning: WARNING: CPU: 2 PID: 3492 at ../fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80 sysfs: cannot create duplicate filename '/module/saa7146/drivers' Modules linked in: hexium_gemini(+) mxb(+) ... ... Call Trace: ... [<ffffffff812e63a2>] sysfs_warn_dup+0x62/0x80 [<ffffffff812e6487>] sysfs_create_dir_ns+0x77/0x90 [<ffffffff8140f2c4>] kobject_add_internal+0xb4/0x340 [<ffffffff8140f5b8>] kobject_add+0x68/0xb0 [<ffffffff8140f631>] kobject_create_and_add+0x31/0x70 [<ffffffff8157a703>] module_add_driver+0xc3/0xd0 [<ffffffff8155e5d4>] bus_add_driver+0x154/0x280 [<ffffffff815604c0>] driver_register+0x60/0xe0 [<ffffffff8145bed0>] __pci_register_driver+0x60/0x70 [<ffffffffa0273e14>] saa7146_register_extension+0x64/0x90 [saa7146] [<ffffffffa0033011>] hexium_init_module+0x11/0x1000 [hexium_gemini] ... As can be (mostly) seen, driver_register causes this call sequence: -> bus_add_driver -> module_add_driver -> module_create_drivers_dir The last one creates "drivers" directory in /sys/module/<...>. When this is done in parallel, the directory is attempted to be created twice at the same time. This can be easily reproduced by loading mxb and hexium_gemini in parallel: while :; do modprobe mxb & modprobe hexium_gemini wait rmmod mxb hexium_gemini saa7146_vv saa7146 done saa7146 calls pci_register_driver for both mxb and hexium_gemini, which means /sys/module/saa7146/drivers is to be created for both of them. Fix this by a new mutex in module_create_drivers_dir which makes the test-and-create "drivers" dir atomic. I inverted the condition and removed 'return' to avoid multiple unlocks or a goto. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Fixes: fe480a26 (Modules: only add drivers/ direcory if needed) Cc: v2.6.21+ <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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J. Bruce Fields authored
[ Upstream commit d50039ea ] Also simplify the logic a bit. Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields <bfields@redhat.com> Acked-by: Trond Myklebust <trondmy@primarydata.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Lyude authored
[ Upstream commit 476490a9 ] Thanks to Ville Syrjälä for pointing me towards the cause of this issue. Unfortunately one of the sideaffects of having the refclk for a DPLL set to SSC is that as long as it's set to SSC, the GPU will prevent us from powering down any of the pipes or transcoders using it. A couple of BIOSes enable SSC in both PCH_DREF_CONTROL and in the DPLL configurations. This causes issues on the first modeset, since we don't expect SSC to be left on and as a result, can't successfully power down the pipes or the transcoders using it. Here's an example from this Dell OptiPlex 990: [drm:intel_modeset_init] SSC enabled by BIOS, overriding VBT which says disabled [drm:intel_modeset_init] 2 display pipes available. [drm:intel_update_cdclk] Current CD clock rate: 400000 kHz [drm:intel_update_max_cdclk] Max CD clock rate: 400000 kHz [drm:intel_update_max_cdclk] Max dotclock rate: 360000 kHz vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem [drm:intel_crt_reset] crt adpa set to 0xf40000 [drm:intel_dp_init_connector] Adding DP connector on port C [drm:intel_dp_aux_init] registering DPDDC-C bus for card0-DP-1 [drm:ironlake_init_pch_refclk] has_panel 0 has_lvds 0 has_ck505 0 [drm:ironlake_init_pch_refclk] Disabling SSC entirely … later we try committing the first modeset … [drm:intel_dump_pipe_config] [CRTC:26][modeset] config ffff88041b02e800 for pipe A [drm:intel_dump_pipe_config] cpu_transcoder: A … [drm:intel_dump_pipe_config] dpll_hw_state: dpll: 0xc4016001, dpll_md: 0x0, fp0: 0x20e08, fp1: 0x30d07 [drm:intel_dump_pipe_config] planes on this crtc [drm:intel_dump_pipe_config] STANDARD PLANE:23 plane: 0.0 idx: 0 enabled [drm:intel_dump_pipe_config] FB:42, fb = 800x600 format = 0x34325258 [drm:intel_dump_pipe_config] scaler:0 src (0, 0) 800x600 dst (0, 0) 800x600 [drm:intel_dump_pipe_config] CURSOR PLANE:25 plane: 0.1 idx: 1 disabled, scaler_id = 0 [drm:intel_dump_pipe_config] STANDARD PLANE:27 plane: 0.1 idx: 2 disabled, scaler_id = 0 [drm:intel_get_shared_dpll] CRTC:26 allocated PCH DPLL A [drm:intel_get_shared_dpll] using PCH DPLL A for pipe A [drm:ilk_audio_codec_disable] Disable audio codec on port C, pipe A [drm:intel_disable_pipe] disabling pipe A ------------[ cut here ]------------ WARNING: CPU: 1 PID: 130 at drivers/gpu/drm/i915/intel_display.c:1146 intel_disable_pipe+0x297/0x2d0 [i915] pipe_off wait timed out … ---[ end trace 94fc8aa03ae139e8 ]--- [drm:intel_dp_link_down] [drm:ironlake_crtc_disable [i915]] *ERROR* failed to disable transcoder A Later modesets succeed since they reset the DPLL's configuration anyway, but this is enough to get stuck with a big fat warning in dmesg. A better solution would be to add refcounts for the SSC source, but for now leaving the source clock on should suffice. Changes since v4: - Fix calculation of final for systems with LVDS panels (fixes BUG() on CI test suite) Changes since v3: - Move temp variable into loop - Move checks for using_ssc_source to after we've figured out has_ck505 - Add using_ssc_source to debug output Changes since v2: - Fix debug output for when we disable the CPU source Changes since v1: - Leave the SSC source clock on instead of just shutting it off on all of the DPLL configurations. Cc: stable@vger.kernel.org Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Lyude <cpaul@redhat.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1465916649-10228-1-git-send-email-cpaul@redhat.comSigned-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Andrey Ryabinin authored
[ Upstream commit 57675cb9 ] Lengthy output of sysrq-w may take a lot of time on slow serial console. Currently we reset NMI-watchdog on the current CPU to avoid spurious lockup messages. Sometimes this doesn't work since softlockup watchdog might trigger on another CPU which is waiting for an IPI to proceed. We reset softlockup watchdogs on all CPUs, but we do this only after listing all tasks, and this may be too late on a busy system. So, reset watchdogs CPUs earlier, in for_each_process_thread() loop. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1465474805-14641-1-git-send-email-aryabinin@virtuozzo.comSigned-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Masami Hiramatsu authored
[ Upstream commit dcfc4724 ] Fix kprobe_fault_handler() to clear the TF (trap flag) bit of the flags register in the case of a fault fixup on single-stepping. If we put a kprobe on the instruction which caused a page fault (e.g. actual mov instructions in copy_user_*), that fault happens on the single-stepping buffer. In this case, kprobes resets running instance so that the CPU can retry execution on the original ip address. However, current code forgets to reset the TF bit. Since this fault happens with TF bit set for enabling single-stepping, when it retries, it causes a debug exception and kprobes can not handle it because it already reset itself. On the most of x86-64 platform, it can be easily reproduced by using kprobe tracer. E.g. # cd /sys/kernel/debug/tracing # echo p copy_user_enhanced_fast_string+5 > kprobe_events # echo 1 > events/kprobes/enable And you'll see a kernel panic on do_debug(), since the debug trap is not handled by kprobes. To fix this problem, we just need to clear the TF bit when resetting running kprobe. Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org> Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: systemtap@sourceware.org Cc: stable@vger.kernel.org # All the way back to ancient kernels Link: http://lkml.kernel.org/r/20160611140648.25885.37482.stgit@devbox [ Updated the comments. ] Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Michal Suchanek authored
[ Upstream commit 719bd654 ] The trasfer timeout is fixed at 1000 ms. Reading a 4Mbyte flash over 1MHz SPI bus takes way longer than that. Calculate the timeout from the actual time the transfer is supposed to take and multiply by 2 for good measure. Signed-off-by: Michal Suchanek <hramrach@gmail.com> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Marcus Weseloh authored
[ Upstream commit 47284e3e ] Allow transfers to set the transmission speed rather than using the device max_speed_hz value. The SPI core makes sure that the speed_hz value is always set on the transfer. Signed-off-by: Marcus Weseloh <mweseloh42@gmail.com> Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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- 11 Jul, 2016 24 commits
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Michal Suchanek authored
[ Upstream commit 6d9fe44b ] When testing SPI without DMA I noticed that filling the FIFO on the spi controller causes timeout. Always leave room for one byte in the FIFO. Signed-off-by: Michal Suchanek <hramrach@gmail.com> Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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James Hogan authored
[ Upstream commit 797179bc ] Copy __kvm_mips_vcpu_run() into unmapped memory, so that we can never get a TLB refill exception in it when KVM is built as a module. This was observed to happen with the host MIPS kernel running under QEMU, due to a not entirely transparent optimisation in the QEMU TLB handling where TLB entries replaced with TLBWR are copied to a separate part of the TLB array. Code in those pages continue to be executable, but those mappings persist only until the next ASID switch, even if they are marked global. An ASID switch happens in __kvm_mips_vcpu_run() at exception level after switching to the guest exception base. Subsequent TLB mapped kernel instructions just prior to switching to the guest trigger a TLB refill exception, which enters the guest exception handlers without updating EPC. This appears as a guest triggered TLB refill on a host kernel mapped (host KSeg2) address, which is not handled correctly as user (guest) mode accesses to kernel (host) segments always generate address error exceptions. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: kvm@vger.kernel.org Cc: linux-mips@linux-mips.org Cc: <stable@vger.kernel.org> # 3.10.x- Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Oscar authored
[ Upstream commit ea1d39a3 ] Fix warning about tainted kernel because usb-otg-fsm has no license. WARNING: with this patch usb-otg-fsm module can be loaded but then the kernel will hang. Tested with a udoo quad board. Cc: <stable@vger.kernel.org> #v4.1+ Signed-off-by: Oscar <oscar@naiandei.net> Signed-off-by: Peter Chen <peter.chen@nxp.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Alex Deucher authored
[ Upstream commit 05082b8b ] When executing in a PCI passthrough based virtuzliation environment, the hypervisor will usually attempt to send a PCIe bus reset signal to the ASIC when the VM reboots. In this scenario, the card is not correctly initialized, but we still consider it to be posted. Therefore, in a passthrough based environemnt we should always post the card to guarantee it is in a good state for driver initialization. Ported from amdgpu commit: amdgpu: fix asic initialization for virtualized environments Cc: Andres Rodriguez <andres.rodriguez@amd.com> Cc: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Linus Walleij authored
[ Upstream commit 19ced623 ] The hash buffer is really HASH_BLOCK_SIZE bytes, someone must have thought that memmove takes n*u32 words by mistake. Tests work as good/bad as before after this patch. Cc: Joakim Bech <joakim.bech@linaro.org> Cc: stable@vger.kernel.org Reported-by: David Binderman <linuxdev.baldrick@gmail.com> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Steve Capper authored
[ Upstream commit 56530f5d ] Currently pmd_mknotpresent will use a zero entry to respresent an invalidated pmd. Unfortunately this definition clashes with pmd_none, thus it is possible for a race condition to occur if zap_pmd_range sees pmd_none whilst __split_huge_pmd_locked is running too with pmdp_invalidate just called. This patch fixes the race condition by modifying pmd_mknotpresent to create non-zero faulting entries (as is done in other architectures), removing the ambiguity with pmd_none. [catalin.marinas@arm.com: using L_PMD_SECT_VALID instead of PMD_TYPE_SECT] Fixes: 8d962507 ("ARM: mm: Transparent huge page support for LPAE systems.") Cc: <stable@vger.kernel.org> # 3.11+ Reported-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Steve Capper <steve.capper@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Will Deacon authored
[ Upstream commit 62453188 ] In a subsequent patch, pmd_mknotpresent will clear the valid bit of the pmd entry, resulting in a not-present entry from the hardware's perspective. Unfortunately, pmd_present simply checks for a non-zero pmd value and will therefore continue to return true even after a pmd_mknotpresent operation. Since pmd_mknotpresent is only used for managing huge entries, this is only an issue for the 3-level case. This patch fixes the 3-level pmd_present implementation to take into account the valid bit. For bisectability, the change is made before the fix to pmd_mknotpresent. [catalin.marinas@arm.com: comment update regarding pmd_mknotpresent patch] Fixes: 8d962507 ("ARM: mm: Transparent huge page support for LPAE systems.") Cc: <stable@vger.kernel.org> # 3.11+ Cc: Russell King <linux@armlinux.org.uk> Cc: Steve Capper <Steve.Capper@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Wei Fang authored
[ Upstream commit 72d8c36e ] sas_ata_strategy_handler() adds the works of the ata error handler to system_unbound_wq. This workqueue asynchronously runs work items, so the ata error handler will be performed concurrently on different CPUs. In this case, ->host_failed will be decreased simultaneously in scsi_eh_finish_cmd() on different CPUs, and become abnormal. It will lead to permanently inequality between ->host_failed and ->host_busy, and scsi error handler thread won't start running. IO errors after that won't be handled. Since all scmds must have been handled in the strategy handler, just remove the decrement in scsi_eh_finish_cmd() and zero ->host_busy after the strategy handler to fix this race. Fixes: 50824d6c ("[SCSI] libsas: async ata-eh") Cc: stable@vger.kernel.org Signed-off-by: Wei Fang <fangwei1@huawei.com> Reviewed-by: James Bottomley <jejb@linux.vnet.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Thierry Reding authored
[ Upstream commit f8a15a96 ] There are three EHCI controllers on Tegra SoCs, each with its own reset line. However, the first controller contains a set of UTMI configuration registers that are shared with its siblings. These registers will only be reset as part of the first controller's reset. For proper operation it must be ensured that the UTMI configuration registers are reset before any of the EHCI controllers are enabled, irrespective of the probe order. Commit a47cc24c ("USB: EHCI: tegra: Fix probe order issue leading to broken USB") introduced code that ensures the first controller is always reset before setting up any of the controllers, and is never again reset afterwards. This code, however, grabs the wrong reset. Each EHCI controller has two reset controls attached: 1) the USB controller reset and 2) the UTMI pads reset (really the first controller's reset). In order to reset the UTMI pads registers the code must grab the second reset, but instead it grabbing the first. Fixes: a47cc24c ("USB: EHCI: tegra: Fix probe order issue leading to broken USB") Acked-by: Jon Hunter <jonathanh@nvidia.com> Cc: stable@vger.kernel.org Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Andrew Goodbody authored
[ Upstream commit 7b2c17f8 ] Ensure that the endpoint is stopped by clearing REQPKT before clearing DATAERR_NAKTIMEOUT before rotating the queue on the dedicated bulk endpoint. This addresses an issue where a race could result in the endpoint receiving data before it was reprogrammed resulting in a warning about such data from musb_rx_reinit before it was thrown away. The data thrown away was a valid packet that had been correctly ACKed which meant the host and device got out of sync. Signed-off-by: Andrew Goodbody <andrew.goodbody@cambrionix.com> Cc: stable@vger.kernel.org Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Andrew Goodbody authored
[ Upstream commit f3eec0cf ] shared_fifo endpoints would only get a previous tx state cleared out, the rx state was only cleared for non shared_fifo endpoints Change this so that the rx state is cleared for all endpoints. This addresses an issue that resulted in rx packets being dropped silently. Signed-off-by: Andrew Goodbody <andrew.goodbody@cambrionix.com> Cc: stable@vger.kernel.org Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Hans de Goede authored
[ Upstream commit d95815ba ] I got one of these cards for testing uas with, it seems that with streams it dma-s all over the place, corrupting memory. On my first tests it managed to dma over the BIOS of the motherboard somehow and completely bricked it. Tests on another motherboard show that it does work with streams disabled. Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Hans de Goede authored
[ Upstream commit 32cb0b37 ] The Acer C120 LED Projector is a USB-3 connected pico projector which takes both its power and video data from USB-3. In combination with some hubs this device does not play well with lpm, so disable lpm for it. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Hans de Goede authored
[ Upstream commit 81099f97 ] Properly sort all the entries by vendor id. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Thomas Petazzoni authored
[ Upstream commit de95c40d ] On some platforms, the clocks might be registered by a platform driver. When this is the case, the clock platform driver may very well be probed after xhci-plat, in which case the first probe() invocation of xhci-plat will receive -EPROBE_DEFER as the return value of devm_clk_get(). The current code handles that as a normal error, and simply assumes that this means that the system doesn't have a clock for the XHCI controller, and continues probing without calling clk_prepare_enable(). Unfortunately, this doesn't work on systems where the XHCI controller does have a clock, but that clock is provided by another platform driver. In order to fix this situation, we handle the -EPROBE_DEFER error condition specially, and abort the XHCI controller probe(). It will be retried later automatically, the clock will be available, devm_clk_get() will succeed, and the probe() will continue with the clock prepared and enabled as expected. In practice, such issue is seen on the ARM64 Marvell 7K/8K platform, where the clocks are registered by a platform driver. Cc: <stable@vger.kernel.org> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Mathias Nyman authored
[ Upstream commit 3425aa03 ] If commands timeout we mark them for abortion, then stop the command ring, and turn the commands to no-ops and finally restart the command ring. If the host is working properly the no-op commands will finish and pending completions are called. If we notice the host is failing, driver clears the command ring and completes, deletes and frees all pending commands. There are two separate cases reported where host is believed to work properly but is not. In the first case we successfully stop the ring but no abort or stop command ring event is ever sent and host locks up. The second case is if a host is removed, command times out and driver believes the ring is stopped, and assumes it will be restarted, but actually ends up timing out on the same command forever. If one of the pending commands has the xhci->mutex held it will block xhci_stop() in the remove codepath which otherwise would cleanup pending commands. Add a check that clears all pending commands in case host is removed, or we are stuck timing out on the same command. Also restart the command timeout timer when stopping the command ring to ensure we recive an ring stop/abort event. Cc: stable <stable@vger.kernel.org> Tested-by: Joe Lawrence <joe.lawrence@stratus.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Oliver Neukum authored
[ Upstream commit ed596a4a ] Flushing a work that reschedules itself is not a sensible operation. It needs to be killed. Failure to do so leads to a kernel panic in the timer code. CC: stable@vger.kernel.org Signed-off-by: Oliver Neukum <ONeukum@suse.com> Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Bin Liu authored
[ Upstream commit d246dcb2 ] [ 40.467381] ============================================= [ 40.473013] [ INFO: possible recursive locking detected ] [ 40.478651] 4.6.0-08691-g7f3db9a #37 Not tainted [ 40.483466] --------------------------------------------- [ 40.489098] usb/733 is trying to acquire lock: [ 40.493734] (&(&dev->lock)->rlock){-.....}, at: [<bf129288>] ep0_complete+0x18/0xdc [gadgetfs] [ 40.502882] [ 40.502882] but task is already holding lock: [ 40.508967] (&(&dev->lock)->rlock){-.....}, at: [<bf12a420>] ep0_read+0x20/0x5e0 [gadgetfs] [ 40.517811] [ 40.517811] other info that might help us debug this: [ 40.524623] Possible unsafe locking scenario: [ 40.524623] [ 40.530798] CPU0 [ 40.533346] ---- [ 40.535894] lock(&(&dev->lock)->rlock); [ 40.540088] lock(&(&dev->lock)->rlock); [ 40.544284] [ 40.544284] *** DEADLOCK *** [ 40.544284] [ 40.550461] May be due to missing lock nesting notation [ 40.550461] [ 40.557544] 2 locks held by usb/733: [ 40.561271] #0: (&f->f_pos_lock){+.+.+.}, at: [<c02a6114>] __fdget_pos+0x40/0x48 [ 40.569219] #1: (&(&dev->lock)->rlock){-.....}, at: [<bf12a420>] ep0_read+0x20/0x5e0 [gadgetfs] [ 40.578523] [ 40.578523] stack backtrace: [ 40.583075] CPU: 0 PID: 733 Comm: usb Not tainted 4.6.0-08691-g7f3db9a #37 [ 40.590246] Hardware name: Generic AM33XX (Flattened Device Tree) [ 40.596625] [<c010ffbc>] (unwind_backtrace) from [<c010c1bc>] (show_stack+0x10/0x14) [ 40.604718] [<c010c1bc>] (show_stack) from [<c04207fc>] (dump_stack+0xb0/0xe4) [ 40.612267] [<c04207fc>] (dump_stack) from [<c01886ec>] (__lock_acquire+0xf68/0x1994) [ 40.620440] [<c01886ec>] (__lock_acquire) from [<c0189528>] (lock_acquire+0xd8/0x238) [ 40.628621] [<c0189528>] (lock_acquire) from [<c06ad6b4>] (_raw_spin_lock_irqsave+0x38/0x4c) [ 40.637440] [<c06ad6b4>] (_raw_spin_lock_irqsave) from [<bf129288>] (ep0_complete+0x18/0xdc [gadgetfs]) [ 40.647339] [<bf129288>] (ep0_complete [gadgetfs]) from [<bf10a728>] (musb_g_giveback+0x118/0x1b0 [musb_hdrc]) [ 40.657842] [<bf10a728>] (musb_g_giveback [musb_hdrc]) from [<bf108768>] (musb_g_ep0_queue+0x16c/0x188 [musb_hdrc]) [ 40.668772] [<bf108768>] (musb_g_ep0_queue [musb_hdrc]) from [<bf12a944>] (ep0_read+0x544/0x5e0 [gadgetfs]) [ 40.678963] [<bf12a944>] (ep0_read [gadgetfs]) from [<c0284470>] (__vfs_read+0x20/0x110) [ 40.687414] [<c0284470>] (__vfs_read) from [<c0285324>] (vfs_read+0x88/0x114) [ 40.694864] [<c0285324>] (vfs_read) from [<c0286150>] (SyS_read+0x44/0x9c) [ 40.702051] [<c0286150>] (SyS_read) from [<c0107820>] (ret_fast_syscall+0x0/0x1c) This is caused by the spinlock bug in ep0_read(). Fix the two other deadlock sources in gadgetfs_setup() too. Cc: <stable@vger.kernel.org> # v3.16+ Signed-off-by: Bin Liu <b-liu@ti.com> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Steinar H. Gunderson authored
[ Upstream commit 4879efb3 ] dwc3-exynos has two problems during init if the regulators are slow to come up (for instance if the I2C bus driver is not on the initramfs) and return probe deferral. First, every time this happens, the driver leaks the USB phys created; they need to be deallocated on error. Second, since the phy devices are created before the regulators fail, this means that there's a new device to re-trigger deferred probing, which causes it to essentially go into a busy loop of re-probing the device until the regulators come up. Move the phy creation to after the regulators have succeeded, and also fix cleanup on failure. On my ODROID XU4 system (with Debian's initramfs which doesn't contain the I2C driver), this reduces the number of probe attempts (for each of the two controllers) from more than 2000 to eight. Signed-off-by: Steinar H. Gunderson <sesse@google.com> Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reviewed-by: Vivek Gautam <gautam.vivek@samsung.com> Fixes: d720f057 ("usb: dwc3: exynos: add nop transceiver support") Cc: <stable@vger.kernel.org> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Vivek Gautam authored
[ Upstream commit c1a3acaa ] There's no need to keep one local variable for clock, and then assign the same to 'clk' member of dwc3_exynos. Just cleaning it up. Signed-off-by: Vivek Gautam <gautam.vivek@samsung.com> Signed-off-by: Felipe Balbi <balbi@ti.com> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Wenwei Tao authored
[ Upstream commit b00c52da ] When create css failed, before call css_free_rcu_fn, we remove the css id and exit the percpu_ref, but we will do these again in css_free_work_fn, so they are redundant. Especially the css id, that would cause problem if we remove it twice, since it may be assigned to another css after the first remove. tj: This was broken by two commits updating the free path without synchronizing the creation failure path. This can be easily triggered by trying to create more than 64k memory cgroups. Signed-off-by: Wenwei Tao <ww.tao0320@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Vladimir Davydov <vdavydov@parallels.com> Fixes: 9a1049da ("percpu-refcount: require percpu_ref to be exited explicitly") Fixes: 01e58659 ("cgroup: release css->id after css_free") Cc: stable@vger.kernel.org # v3.17+ Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Tejun Heo authored
[ Upstream commit 6710e594 ] For non-atomic allocations, pcpu_alloc() can try to extend the area map synchronously after dropping pcpu_lock; however, the extension wasn't synchronized against chunk destruction and the chunk might get freed while extension is in progress. This patch fixes the bug by putting most of non-atomic allocations under pcpu_alloc_mutex to synchronize against pcpu_balance_work which is responsible for async chunk management including destruction. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Reported-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: stable@vger.kernel.org # v3.18+ Fixes: 1a4d7607 ("percpu: implement asynchronous chunk population") Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Tejun Heo authored
[ Upstream commit 4f996e23 ] Atomic allocations can trigger async map extensions which is serviced by chunk->map_extend_work. pcpu_balance_work which is responsible for destroying idle chunks wasn't synchronizing properly against chunk->map_extend_work and may end up freeing the chunk while the work item is still in flight. This patch fixes the bug by rolling async map extension operations into pcpu_balance_work. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-and-tested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Reported-by: Vlastimil Babka <vbabka@suse.cz> Reported-by: Sasha Levin <sasha.levin@oracle.com> Cc: stable@vger.kernel.org # v3.18+ Fixes: 9c824b6a ("percpu: make sure chunk->map array has available space") Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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Rainer Weikusat authored
[ Upstream commit c845acb3 ] On 2015/11/06, Dmitry Vyukov reported a deadlock involving the splice system call and AF_UNIX sockets, http://lists.openwall.net/netdev/2015/11/06/24 The situation was analyzed as (a while ago) A: socketpair() B: splice() from a pipe to /mnt/regular_file does sb_start_write() on /mnt C: try to freeze /mnt wait for B to finish with /mnt A: bind() try to bind our socket to /mnt/new_socket_name lock our socket, see it not bound yet decide that it needs to create something in /mnt try to do sb_start_write() on /mnt, block (it's waiting for C). D: splice() from the same pipe to our socket lock the pipe, see that socket is connected try to lock the socket, block waiting for A B: get around to actually feeding a chunk from pipe to file, try to lock the pipe. Deadlock. on 2015/11/10 by Al Viro, http://lists.openwall.net/netdev/2015/11/10/4 The patch fixes this by removing the kern_path_create related code from unix_mknod and executing it as part of unix_bind prior acquiring the readlock of the socket in question. This means that A (as used above) will sb_start_write on /mnt before it acquires the readlock, hence, it won't indirectly block B which first did a sb_start_write and then waited for a thread trying to acquire the readlock. Consequently, A being blocked by C waiting for B won't cause a deadlock anymore (effectively, both A and B acquire two locks in opposite order in the situation described above). Dmitry Vyukov(<dvyukov@google.com>) tested the original patch. Signed-off-by: Rainer Weikusat <rweikusat@mobileactivedefense.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
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