- 25 Aug, 2015 36 commits
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Dave Airlie authored
commit 7f98ca45 upstream. We apparantly get a hotplug irq before we've initialised modesetting, [drm] Loading R100 Microcode BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<c125f56f>] __mutex_lock_slowpath+0x23/0x91 *pde = 00000000 Oops: 0002 [#1] Modules linked in: radeon(+) drm_kms_helper ttm drm i2c_algo_bit backlight pcspkr psmouse evdev sr_mod input_leds led_class cdrom sg parport_pc parport floppy intel_agp intel_gtt lpc_ich acpi_cpufreq processor button mfd_core agpgart uhci_hcd ehci_hcd rng_core snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm usbcore usb_common i2c_i801 i2c_core snd_timer snd soundcore thermal_sys CPU: 0 PID: 15 Comm: kworker/0:1 Not tainted 4.2.0-rc7-00015-gbf674028 #111 Hardware name: MicroLink /D850MV , BIOS MV85010A.86A.0067.P24.0304081124 04/08/2003 Workqueue: events radeon_hotplug_work_func [radeon] task: f6ca5900 ti: f6d3e000 task.ti: f6d3e000 EIP: 0060:[<c125f56f>] EFLAGS: 00010282 CPU: 0 EIP is at __mutex_lock_slowpath+0x23/0x91 EAX: 00000000 EBX: f5e900fc ECX: 00000000 EDX: fffffffe ESI: f6ca5900 EDI: f5e90100 EBP: f5e90000 ESP: f6d3ff0c DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 CR0: 8005003b CR2: 00000000 CR3: 36f61000 CR4: 000006d0 Stack: f5e90100 00000000 c103c4c1 f6d2a5a0 f5e900fc f6df394c c125f162 f8b0faca f6d2a5a0 c138ca00 f6df394c f7395600 c1034741 00d40000 00000000 f6d2a5a0 c138ca00 f6d2a5b8 c138ca10 c1034b58 00000001 f6d40000 f6ca5900 f6d0c940 Call Trace: [<c103c4c1>] ? dequeue_task_fair+0xa4/0xb7 [<c125f162>] ? mutex_lock+0x9/0xa [<f8b0faca>] ? radeon_hotplug_work_func+0x17/0x57 [radeon] [<c1034741>] ? process_one_work+0xfc/0x194 [<c1034b58>] ? worker_thread+0x18d/0x218 [<c10349cb>] ? rescuer_thread+0x1d5/0x1d5 [<c103742a>] ? kthread+0x7b/0x80 [<c12601c0>] ? ret_from_kernel_thread+0x20/0x30 [<c10373af>] ? init_completion+0x18/0x18 Code: 42 08 e8 8e a6 dd ff c3 57 56 53 83 ec 0c 8b 35 48 f7 37 c1 8b 10 4a 74 1a 89 c3 8d 78 04 8b 40 08 89 63 Reported-and-Tested-by:
Meelis Roos <mroos@linux.ee> Signed-off-by:
Dave Airlie <airlied@redhat.com> Signed-off-by:
Jiri Slaby <jslaby@suse.cz>
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Mika Westerberg authored
commit 1abf25a2 upstream. Using -1 as platform device id means that the platform driver core will not assign any id to the device (the device name will not have id at all). This results problems on systems that have multiple PCHs (Platform Controller HUBs) because all of them also include their own copy of LPC device. All the subsequent device creations will fail because there already exists platform device with the same name. Fix this by passing PLATFORM_DEVID_AUTO as platform device id. This makes the platform device core to allocate new ids automatically. Signed-off-by:
Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by:
Lee Jones <lee.jones@linaro.org> Signed-off-by:
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Jiri Slaby authored
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Ilya Dryomov authored
commit 2761713d upstream. For write/discard obj_requests that involved a copyup method call, the opcode of the first op is CEPH_OSD_OP_CALL and the ->callback is rbd_img_obj_copyup_callback(). The latter frees copyup pages, sets ->xferred and delegates to rbd_img_obj_callback(), the "normal" image object callback, for reporting to block layer and putting refs. rbd_osd_req_callback() however treats CEPH_OSD_OP_CALL as a trivial op, which means obj_request is marked done in rbd_osd_trivial_callback(), *before* ->callback is invoked and rbd_img_obj_copyup_callback() has a chance to run. Marking obj_request done essentially means giving rbd_img_obj_callback() a license to end it at any moment, so if another obj_request from the same img_request is being completed concurrently, rbd_img_obj_end_request() may very well be called on such prematurally marked done request: <obj_request-1/2 reply> handle_reply() rbd_osd_req_callback() rbd_osd_trivial_callback() rbd_obj_request_complete() rbd_img_obj_copyup_callback() rbd_img_obj_callback() <obj_request-2/2 reply> handle_reply() rbd_osd_req_callback() rbd_osd_trivial_callback() for_each_obj_request(obj_request->img_request) { rbd_img_obj_end_request(obj_request-1/2) rbd_img_obj_end_request(obj_request-2/2) <-- } Calling rbd_img_obj_end_request() on such a request leads to trouble, in particular because its ->xfferred is 0. We report 0 to the block layer with blk_update_request(), get back 1 for "this request has more data in flight" and then trip on rbd_assert(more ^ (which == img_request->obj_request_count)); with rhs (which == ...) being 1 because rbd_img_obj_end_request() has been called for both requests and lhs (more) being 1 because we haven't got a chance to set ->xfferred in rbd_img_obj_copyup_callback() yet. To fix this, leverage that rbd wants to call class methods in only two cases: one is a generic method call wrapper (obj_request is standalone) and the other is a copyup (obj_request is part of an img_request). So make a dedicated handler for CEPH_OSD_OP_CALL and directly invoke rbd_img_obj_copyup_callback() from it if obj_request is part of an img_request, similar to how CEPH_OSD_OP_READ handler invokes rbd_img_obj_request_read_callback(). Since rbd_img_obj_copyup_callback() is now being called from the OSD request callback (only), it is renamed to rbd_osd_copyup_callback(). Cc: Alex Elder <elder@linaro.org> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Reviewed-by:
Alex Elder <elder@linaro.org> [idryomov@gmail.com: backport to < 3.18: context] Signed-off-by:
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Alex Deucher authored
commit e037239e upstream. Signed-off-by:
Alex Deucher <alexander.deucher@amd.com> Signed-off-by:
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Michael Walle authored
commit 5c16179b upstream. The commit de3910eb ("edac: change the mem allocation scheme to make Documentation/kobject.txt happy") changed the memory allocation for the csrows member. But ppc4xx_edac was forgotten in the patch. Fix it. Signed-off-by:
Michael Walle <michael@walle.cc> Cc: linux-edac <linux-edac@vger.kernel.org> Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com> Link: http://lkml.kernel.org/r/1437469253-8611-1-git-send-email-michael@walle.ccSigned-off-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
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Richard Weinberger authored
commit c0ddc8c7 upstream. In kbuild it is allowed to define objects in files named "Makefile" and "Kbuild". Currently localmodconfig reads objects only from "Makefile"s and misses modules like nouveau. Link: http://lkml.kernel.org/r/1437948415-16290-1-git-send-email-richard@nod.atReported-and-tested-by:
Leonidas Spyropoulos <artafinde@gmail.com> Signed-off-by:
Richard Weinberger <richard@nod.at> Signed-off-by:
Steven Rostedt <rostedt@goodmis.org> Signed-off-by:
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Joe Thornber authored
commit 7f518ad0 upstream. The device details and mapping trees were just being decremented before. Now btree_del() is called to do a deep delete. Signed-off-by:
Joe Thornber <ejt@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Signed-off-by:
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Peter Zijlstra authored
commit fed66e2c upstream. Vince reported that the fasync signal stuff doesn't work proper for inherited events. So fix that. Installing fasync allocates memory and sets filp->f_flags |= FASYNC, which upon the demise of the file descriptor ensures the allocation is freed and state is updated. Now for perf, we can have the events stick around for a while after the original FD is dead because of references from child events. So we cannot copy the fasync pointer around. We can however consistently use the parent's fasync, as that will be updated. Reported-and-Tested-by:
Vince Weaver <vincent.weaver@maine.edu> Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho deMelo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: eranian@google.com Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twinsSigned-off-by:
Ingo Molnar <mingo@kernel.org> Signed-off-by:
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Bob Liu authored
commit 7b076750 upstream. We should consider info->feature_persistent when adding indirect page to list info->indirect_pages, else the BUG_ON() in blkif_free() would be triggered. When we are using persistent grants the indirect_pages list should always be empty because blkfront has pre-allocated enough persistent pages to fill all requests on the ring. Acked-by:
Roger Pau Monné <roger.pau@citrix.com> Signed-off-by:
Bob Liu <bob.liu@oracle.com> Signed-off-by:
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by:
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Wanpeng Li authored
commit 4f32be67 upstream. After trying to drain pages from pagevec/pageset, we try to get reference count of the page again, however, the reference count of the page is not reduced if the page is still not on LRU list. Fix it by adding the put_page() to drop the page reference which is from __get_any_page(). Signed-off-by:
Wanpeng Li <wanpeng.li@hotmail.com> Acked-by:
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Herton R. Krzesinski authored
commit 602b8593 upstream. The current semaphore code allows a potential use after free: in exit_sem we may free the task's sem_undo_list while there is still another task looping through the same semaphore set and cleaning the sem_undo list at freeary function (the task called IPC_RMID for the same semaphore set). For example, with a test program [1] running which keeps forking a lot of processes (which then do a semop call with SEM_UNDO flag), and with the parent right after removing the semaphore set with IPC_RMID, and a kernel built with CONFIG_SLAB, CONFIG_SLAB_DEBUG and CONFIG_DEBUG_SPINLOCK, you can easily see something like the following in the kernel log: Slab corruption (Not tainted): kmalloc-64 start=ffff88003b45c1c0, len=64 000: 6b 6b 6b 6b 6b 6b 6b 6b 00 6b 6b 6b 6b 6b 6b 6b kkkkkkkk.kkkkkkk 010: ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff ....kkkk........ Prev obj: start=ffff88003b45c180, len=64 000: 00 00 00 00 ad 4e ad de ff ff ff ff 5a 5a 5a 5a .....N......ZZZZ 010: ff ff ff ff ff ff ff ff c0 fb 01 37 00 88 ff ff ...........7.... Next obj: start=ffff88003b45c200, len=64 000: 00 00 00 00 ad 4e ad de ff ff ff ff 5a 5a 5a 5a .....N......ZZZZ 010: ff ff ff ff ff ff ff ff 68 29 a7 3c 00 88 ff ff ........h).<.... BUG: spinlock wrong CPU on CPU#2, test/18028 general protection fault: 0000 [#1] SMP Modules linked in: 8021q mrp garp stp llc nf_conntrack_ipv4 nf_defrag_ipv4 ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables binfmt_misc ppdev input_leds joydev parport_pc parport floppy serio_raw virtio_balloon virtio_rng virtio_console virtio_net iosf_mbi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcspkr qxl ttm drm_kms_helper drm snd_hda_codec_generic i2c_piix4 snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore crc32c_intel virtio_pci virtio_ring virtio pata_acpi ata_generic [last unloaded: speedstep_lib] CPU: 2 PID: 18028 Comm: test Not tainted 4.2.0-rc5+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014 RIP: spin_dump+0x53/0xc0 Call Trace: spin_bug+0x30/0x40 do_raw_spin_unlock+0x71/0xa0 _raw_spin_unlock+0xe/0x10 freeary+0x82/0x2a0 ? _raw_spin_lock+0xe/0x10 semctl_down.clone.0+0xce/0x160 ? __do_page_fault+0x19a/0x430 ? __audit_syscall_entry+0xa8/0x100 SyS_semctl+0x236/0x2c0 ? syscall_trace_leave+0xde/0x130 entry_SYSCALL_64_fastpath+0x12/0x71 Code: 8b 80 88 03 00 00 48 8d 88 60 05 00 00 48 c7 c7 a0 2c a4 81 31 c0 65 8b 15 eb 40 f3 7e e8 08 31 68 00 4d 85 e4 44 8b 4b 08 74 5e <45> 8b 84 24 88 03 00 00 49 8d 8c 24 60 05 00 00 8b 53 04 48 89 RIP [<ffffffff810d6053>] spin_dump+0x53/0xc0 RSP <ffff88003750fd68> ---[ end trace 783ebb76612867a0 ]--- NMI watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [test:18053] Modules linked in: 8021q mrp garp stp llc nf_conntrack_ipv4 nf_defrag_ipv4 ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables binfmt_misc ppdev input_leds joydev parport_pc parport floppy serio_raw virtio_balloon virtio_rng virtio_console virtio_net iosf_mbi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcspkr qxl ttm drm_kms_helper drm snd_hda_codec_generic i2c_piix4 snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore crc32c_intel virtio_pci virtio_ring virtio pata_acpi ata_generic [last unloaded: speedstep_lib] CPU: 3 PID: 18053 Comm: test Tainted: G D 4.2.0-rc5+ #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014 RIP: native_read_tsc+0x0/0x20 Call Trace: ? delay_tsc+0x40/0x70 __delay+0xf/0x20 do_raw_spin_lock+0x96/0x140 _raw_spin_lock+0xe/0x10 sem_lock_and_putref+0x11/0x70 SYSC_semtimedop+0x7bf/0x960 ? handle_mm_fault+0xbf6/0x1880 ? dequeue_task_fair+0x79/0x4a0 ? __do_page_fault+0x19a/0x430 ? kfree_debugcheck+0x16/0x40 ? __do_page_fault+0x19a/0x430 ? __audit_syscall_entry+0xa8/0x100 ? do_audit_syscall_entry+0x66/0x70 ? syscall_trace_enter_phase1+0x139/0x160 SyS_semtimedop+0xe/0x10 SyS_semop+0x10/0x20 entry_SYSCALL_64_fastpath+0x12/0x71 Code: 47 10 83 e8 01 85 c0 89 47 10 75 08 65 48 89 3d 1f 74 ff 7e c9 c3 0f 1f 44 00 00 55 48 89 e5 e8 87 17 04 00 66 90 c9 c3 0f 1f 00 <55> 48 89 e5 0f 31 89 c1 48 89 d0 48 c1 e0 20 89 c9 48 09 c8 c9 Kernel panic - not syncing: softlockup: hung tasks I wasn't able to trigger any badness on a recent kernel without the proper config debugs enabled, however I have softlockup reports on some kernel versions, in the semaphore code, which are similar as above (the scenario is seen on some servers running IBM DB2 which uses semaphore syscalls). The patch here fixes the race against freeary, by acquiring or waiting on the sem_undo_list lock as necessary (exit_sem can race with freeary, while freeary sets un->semid to -1 and removes the same sem_undo from list_proc or when it removes the last sem_undo). After the patch I'm unable to reproduce the problem using the test case [1]. [1] Test case used below: #include <stdio.h> #include <sys/types.h> #include <sys/ipc.h> #include <sys/sem.h> #include <sys/wait.h> #include <stdlib.h> #include <time.h> #include <unistd.h> #include <errno.h> #define NSEM 1 #define NSET 5 int sid[NSET]; void thread() { struct sembuf op; int s; uid_t pid = getuid(); s = rand() % NSET; op.sem_num = pid % NSEM; op.sem_op = 1; op.sem_flg = SEM_UNDO; semop(sid[s], &op, 1); exit(EXIT_SUCCESS); } void create_set() { int i, j; pid_t p; union { int val; struct semid_ds *buf; unsigned short int *array; struct seminfo *__buf; } un; /* Create and initialize semaphore set */ for (i = 0; i < NSET; i++) { sid[i] = semget(IPC_PRIVATE , NSEM, 0644 | IPC_CREAT); if (sid[i] < 0) { perror("semget"); exit(EXIT_FAILURE); } } un.val = 0; for (i = 0; i < NSET; i++) { for (j = 0; j < NSEM; j++) { if (semctl(sid[i], j, SETVAL, un) < 0) perror("semctl"); } } /* Launch threads that operate on semaphore set */ for (i = 0; i < NSEM * NSET * NSET; i++) { p = fork(); if (p < 0) perror("fork"); if (p == 0) thread(); } /* Free semaphore set */ for (i = 0; i < NSET; i++) { if (semctl(sid[i], NSEM, IPC_RMID)) perror("IPC_RMID"); } /* Wait for forked processes to exit */ while (wait(NULL)) { if (errno == ECHILD) break; }; } int main(int argc, char **argv) { pid_t p; srand(time(NULL)); while (1) { p = fork(); if (p < 0) { perror("fork"); exit(EXIT_FAILURE); } if (p == 0) { create_set(); goto end; } /* Wait for forked processes to exit */ while (wait(NULL)) { if (errno == ECHILD) break; }; } end: return 0; } [akpm@linux-foundation.org: use normal comment layout] Signed-off-by:
Herton R. Krzesinski <herton@redhat.com> Acked-by:
Manfred Spraul <manfred@colorfullife.com> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Rafael Aquini <aquini@redhat.com> CC: Aristeu Rozanski <aris@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Signed-off-by:
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Manfred Spraul authored
commit 3ed1f8a9 upstream. sem_lock() did not properly pair memory barriers: !spin_is_locked() and spin_unlock_wait() are both only control barriers. The code needs an acquire barrier, otherwise the cpu might perform read operations before the lock test. As no primitive exists inside <include/spinlock.h> and since it seems noone wants another primitive, the code creates a local primitive within ipc/sem.c. With regards to -stable: The change of sem_wait_array() is a bugfix, the change to sem_lock() is a nop (just a preprocessor redefinition to improve the readability). The bugfix is necessary for all kernels that use sem_wait_array() (i.e.: starting from 3.10). Signed-off-by:
Oleg Nesterov <oleg@redhat.com> Acked-by:
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Michal Hocko authored
commit ecf5fc6e upstream. Nikolay has reported a hang when a memcg reclaim got stuck with the following backtrace: PID: 18308 TASK: ffff883d7c9b0a30 CPU: 1 COMMAND: "rsync" #0 __schedule at ffffffff815ab152 #1 schedule at ffffffff815ab76e #2 schedule_timeout at ffffffff815ae5e5 #3 io_schedule_timeout at ffffffff815aad6a #4 bit_wait_io at ffffffff815abfc6 #5 __wait_on_bit at ffffffff815abda5 #6 wait_on_page_bit at ffffffff8111fd4f #7 shrink_page_list at ffffffff81135445 #8 shrink_inactive_list at ffffffff81135845 #9 shrink_lruvec at ffffffff81135ead #10 shrink_zone at ffffffff811360c3 #11 shrink_zones at ffffffff81136eff #12 do_try_to_free_pages at ffffffff8113712f #13 try_to_free_mem_cgroup_pages at ffffffff811372be #14 try_charge at ffffffff81189423 #15 mem_cgroup_try_charge at ffffffff8118c6f5 #16 __add_to_page_cache_locked at ffffffff8112137d #17 add_to_page_cache_lru at ffffffff81121618 #18 pagecache_get_page at ffffffff8112170b #19 grow_dev_page at ffffffff811c8297 #20 __getblk_slow at ffffffff811c91d6 #21 __getblk_gfp at ffffffff811c92c1 #22 ext4_ext_grow_indepth at ffffffff8124565c #23 ext4_ext_create_new_leaf at ffffffff81246ca8 #24 ext4_ext_insert_extent at ffffffff81246f09 #25 ext4_ext_map_blocks at ffffffff8124a848 #26 ext4_map_blocks at ffffffff8121a5b7 #27 mpage_map_one_extent at ffffffff8121b1fa #28 mpage_map_and_submit_extent at ffffffff8121f07b #29 ext4_writepages at ffffffff8121f6d5 #30 do_writepages at ffffffff8112c490 #31 __filemap_fdatawrite_range at ffffffff81120199 #32 filemap_flush at ffffffff8112041c #33 ext4_alloc_da_blocks at ffffffff81219da1 #34 ext4_rename at ffffffff81229b91 #35 ext4_rename2 at ffffffff81229e32 #36 vfs_rename at ffffffff811a08a5 #37 SYSC_renameat2 at ffffffff811a3ffc #38 sys_renameat2 at ffffffff811a408e #39 sys_rename at ffffffff8119e51e #40 system_call_fastpath at ffffffff815afa89 Dave Chinner has properly pointed out that this is a deadlock in the reclaim code because ext4 doesn't submit pages which are marked by PG_writeback right away. The heuristic was introduced by commit e62e384e ("memcg: prevent OOM with too many dirty pages") and it was applied only when may_enter_fs was specified. The code has been changed by c3b94f44 ("memcg: further prevent OOM with too many dirty pages") which has removed the __GFP_FS restriction with a reasoning that we do not get into the fs code. But this is not sufficient apparently because the fs doesn't necessarily submit pages marked PG_writeback for IO right away. ext4_bio_write_page calls io_submit_add_bh but that doesn't necessarily submit the bio. Instead it tries to map more pages into the bio and mpage_map_one_extent might trigger memcg charge which might end up waiting on a page which is marked PG_writeback but hasn't been submitted yet so we would end up waiting for something that never finishes. Fix this issue by replacing __GFP_IO by may_enter_fs check (for case 2) before we go to wait on the writeback. The page fault path, which is the only path that triggers memcg oom killer since 3.12, shouldn't require GFP_NOFS and so we shouldn't reintroduce the premature OOM killer issue which was originally addressed by the heuristic. As per David Chinner the xfs is doing similar thing since 2.6.15 already so ext4 is not the only affected filesystem. Moreover he notes: : For example: IO completion might require unwritten extent conversion : which executes filesystem transactions and GFP_NOFS allocations. The : writeback flag on the pages can not be cleared until unwritten : extent conversion completes. Hence memory reclaim cannot wait on : page writeback to complete in GFP_NOFS context because it is not : safe to do so, memcg reclaim or otherwise. [tytso@mit.edu: corrected the control flow] Fixes: c3b94f44 ("memcg: further prevent OOM with too many dirty pages") Reported-by:
Nikolay Borisov <kernel@kyup.com> Signed-off-by:
Michal Hocko <mhocko@suse.cz> Signed-off-by:
Hugh Dickins <hughd@google.com> Signed-off-by:
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NeilBrown authored
commit b97e9257 upstream Use separate bitmaps for each nodes in the cluster bitmap_read_sb() validates the bitmap superblock that it reads in. If it finds an inconsistency like a bad magic number or out-of-range version number, it prints an error and returns, but it incorrectly returns zero, so the array is still assembled with the (invalid) bitmap. This means it could try to use a bitmap with a new version number which it therefore does not understand. This bug was introduced in 3.5 and fix as part of a larger patch in 4.1. So the patch is suitable for any -stable kernel in that range. Fixes: 27581e5a ("md/bitmap: centralise allocation of bitmap file pages.") Signed-off-by:
NeilBrown <neilb@suse.com> Reported-by:
GuoQing Jiang <gqjiang@suse.com>
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Al Viro authored
commit f15133df upstream. path_openat() jumps to the wrong place after do_tmpfile() - it has already done path_cleanup() (as part of path_lookupat() called by do_tmpfile()), so doing that again can lead to double fput(). Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Amanieu d'Antras authored
commit 3c00cb5e upstream. This function can leak kernel stack data when the user siginfo_t has a positive si_code value. The top 16 bits of si_code descibe which fields in the siginfo_t union are active, but they are treated inconsistently between copy_siginfo_from_user32, copy_siginfo_to_user32 and copy_siginfo_to_user. copy_siginfo_from_user32 is called from rt_sigqueueinfo and rt_tgsigqueueinfo in which the user has full control overthe top 16 bits of si_code. This fixes the following information leaks: x86: 8 bytes leaked when sending a signal from a 32-bit process to itself. This leak grows to 16 bytes if the process uses x32. (si_code = __SI_CHLD) x86: 100 bytes leaked when sending a signal from a 32-bit process to a 64-bit process. (si_code = -1) sparc: 4 bytes leaked when sending a signal from a 32-bit process to a 64-bit process. (si_code = any) parsic and s390 have similar bugs, but they are not vulnerable because rt_[tg]sigqueueinfo have checks that prevent sending a positive si_code to a different process. These bugs are also fixed for consistency. Signed-off-by:
Amanieu d'Antras <amanieu@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by:
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Amanieu d'Antras authored
commit 26135022 upstream. This function may copy the si_addr_lsb, si_lower and si_upper fields to user mode when they haven't been initialized, which can leak kernel stack data to user mode. Just checking the value of si_code is insufficient because the same si_code value is shared between multiple signals. This is solved by checking the value of si_signo in addition to si_code. Signed-off-by:
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Amanieu d'Antras authored
commit 3ead7c52 upstream. This function may copy the si_addr_lsb field to user mode when it hasn't been initialized, which can leak kernel stack data to user mode. Just checking the value of si_code is insufficient because the same si_code value is shared between multiple signals. This is solved by checking the value of si_signo in addition to si_code. Signed-off-by:
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Andy Lutomirski authored
commit 12e244f4 upstream. The previous fix confused a selector with a segment prefix. Fix it. Compile-tested only. Cc: stable@vger.kernel.org Cc: Juergen Gross <jgross@suse.com> Reported-by:
Andy Lutomirski <luto@kernel.org> Signed-off-by:
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Juergen Gross authored
commit 4809146b upstream. Commit 37868fe1 ("x86/ldt: Make modify_ldt synchronous") introduced a new struct ldt_struct anchored at mm->context.ldt. Adapt the x86 fpu emulation code to use that new structure. Signed-off-by:
Juergen Gross <jgross@suse.com> Reviewed-by:
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Juergen Gross authored
commit 136d9d83 upstream. Commit 37868fe1 ("x86/ldt: Make modify_ldt synchronous") introduced a new struct ldt_struct anchored at mm->context.ldt. convert_ip_to_linear() was changed to reflect this, but indexing into the ldt has to be changed as the pointer is no longer void *. Signed-off-by:
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Andy Lutomirski authored
commit 37868fe1 upstream. modify_ldt() has questionable locking and does not synchronize threads. Improve it: redesign the locking and synchronize all threads' LDTs using an IPI on all modifications. This will dramatically slow down modify_ldt in multithreaded programs, but there shouldn't be any multithreaded programs that care about modify_ldt's performance in the first place. This fixes some fallout from the CVE-2015-5157 fixes. Signed-off-by:
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Peter Zijlstra authored
commit 0a04b016 upstream. I want to use lockless_dereference() from seqlock.h, which would mean including rcupdate.h from it, however rcupdate.h already includes seqlock.h. Avoid this by moving lockless_dereference() into compiler.h. This is somewhat tricky since it uses smp_read_barrier_depends() which isn't available there, but its a CPP macro so we can get away with it. The alternative would be moving it into asm/barrier.h, but that would be updating each arch (I can do if people feel that is more appropriate). Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au> Signed-off-by:
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Paul E. McKenney authored
commit 54ef6df3 upstream. Although rcu_dereference() and friends can be used in situations where object lifetimes are being managed by something other than RCU, the resulting sparse and lockdep-RCU noise can be annoying. This commit therefore supplies a lockless_dereference(), which provides the protection for dereferences without the RCU-related debugging noise. Reported-by:
Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by:
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Peter Zijlstra authored
commit 47933ad4 upstream. A number of situations currently require the heavyweight smp_mb(), even though there is no need to order prior stores against later loads. Many architectures have much cheaper ways to handle these situations, but the Linux kernel currently has no portable way to make use of them. This commit therefore supplies smp_load_acquire() and smp_store_release() to remedy this situation. The new smp_load_acquire() primitive orders the specified load against any subsequent reads or writes, while the new smp_store_release() primitive orders the specifed store against any prior reads or writes. These primitives allow array-based circular FIFOs to be implemented without an smp_mb(), and also allow a theoretical hole in rcu_assign_pointer() to be closed at no additional expense on most architectures. In addition, the RCU experience transitioning from explicit smp_read_barrier_depends() and smp_wmb() to rcu_dereference() and rcu_assign_pointer(), respectively resulted in substantial improvements in readability. It therefore seems likely that replacing other explicit barriers with smp_load_acquire() and smp_store_release() will provide similar benefits. It appears that roughly half of the explicit barriers in core kernel code might be so replaced. [Changelog by PaulMck] Reviewed-by:
Will Deacon <will.deacon@arm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: Michael Ellerman <michael@ellerman.id.au> Cc: Michael Neuling <mikey@neuling.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Victor Kaplansky <VICTORK@il.ibm.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/20131213150640.908486364@infradead.orgSigned-off-by:
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Andy Lutomirski authored
commit 9b6e6a83 upstream. Returning to userspace is tricky: IRET can fail, and ESPFIX can rearrange the stack prior to IRET. The NMI nesting fixup relies on a precise stack layout and atomic IRET. Rather than trying to teach the NMI nesting fixup to handle ESPFIX and failed IRET, punt: run NMIs that came from user mode on the normal kernel stack. This will make some nested NMIs visible to C code, but the C code is okay with that. As a side effect, this should speed up perf: it eliminates an RDMSR when NMIs come from user mode. Signed-off-by:
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Andy Lutomirski authored
commit 0e181bb5 upstream. Now that do_nmi saves CR2, we don't need to save it in asm. Signed-off-by:
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Andy Lutomirski authored
commit 9d050416 upstream. 32-bit kernels handle nested NMIs in C. Enable the exact same handling on 64-bit kernels as well. This isn't currently necessary, but it will become necessary once the asm code starts allowing limited nesting. Signed-off-by:
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NeilBrown authored
commit 423f04d6 upstream. raid1_end_read_request() assumes that the In_sync bits are consistent with the ->degaded count. raid1_spare_active updates the In_sync bit before the ->degraded count and so exposes an inconsistency, as does error() So extend the spinlock in raid1_spare_active() and error() to hide those inconsistencies. This should probably be part of Commit: 34cab6f4 ("md/raid1: fix test for 'was read error from last working device'.") as it addresses the same issue. It fixes the same bug and should go to -stable for same reasons. Fixes: 76073054 ("md/raid1: clean up read_balance.") Signed-off-by:
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Joseph Qi authored
commit 209f7512 upstream. The "BUG_ON(list_empty(&osb->blocked_lock_list))" in ocfs2_downconvert_thread_do_work can be triggered in the following case: ocfs2dc has firstly saved osb->blocked_lock_count to local varibale processed, and then processes the dentry lockres. During the dentry put, it calls iput and then deletes rw, inode and open lockres from blocked list in ocfs2_mark_lockres_freeing. And this causes the variable `processed' to not reflect the number of blocked lockres to be processed, which triggers the BUG. Signed-off-by:
Joseph Qi <joseph.qi@huawei.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Signed-off-by:
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Marcus Gelderie authored
commit de54b9ac upstream. A while back, the message queue implementation in the kernel was improved to use btrees to speed up retrieval of messages, in commit d6629859 ("ipc/mqueue: improve performance of send/recv"). That patch introducing the improved kernel handling of message queues (using btrees) has, as a by-product, changed the meaning of the QSIZE field in the pseudo-file created for the queue. Before, this field reflected the size of the user-data in the queue. Since, it also takes kernel data structures into account. For example, if 13 bytes of user data are in the queue, on my machine the file reports a size of 61 bytes. There was some discussion on this topic before (for example https://lkml.org/lkml/2014/10/1/115). Commenting on a th lkml, Michael Kerrisk gave the following background (https://lkml.org/lkml/2015/6/16/74): The pseudofiles in the mqueue filesystem (usually mounted at /dev/mqueue) expose fields with metadata describing a message queue. One of these fields, QSIZE, as originally implemented, showed the total number of bytes of user data in all messages in the message queue, and this feature was documented from the beginning in the mq_overview(7) page. In 3.5, some other (useful) work happened to break the user-space API in a couple of places, including the value exposed via QSIZE, which now includes a measure of kernel overhead bytes for the queue, a figure that renders QSIZE useless for its original purpose, since there's no way to deduce the number of overhead bytes consumed by the implementation. (The other user-space breakage was subsequently fixed.) This patch removes the accounting of kernel data structures in the queue. Reporting the size of these data-structures in the QSIZE field was a breaking change (see Michael's comment above). Without the QSIZE field reporting the total size of user-data in the queue, there is no way to deduce this number. It should be noted that the resource limit RLIMIT_MSGQUEUE is counted against the worst-case size of the queue (in both the old and the new implementation). Therefore, the kernel overhead accounting in QSIZE is not necessary to help the user understand the limitations RLIMIT imposes on the processes. Signed-off-by:
Marcus Gelderie <redmnic@gmail.com> Acked-by:
Doug Ledford <dledford@redhat.com> Acked-by:
Michael Kerrisk <mtk.manpages@gmail.com> Acked-by:
Davidlohr Bueso <dbueso@suse.de> Cc: David Howells <dhowells@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: John Duffy <jb_duffy@btinternet.com> Cc: Arto Bendiken <arto@bendiken.net> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by:
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Dan Carpenter authored
commit 44008f08 upstream. Smatch complains that we have nested checks for "spdif_present". It turns out the current behavior isn't correct, we should remove the first check and keep the second. Fixes: 1077a024 ('ALSA: hda - Use generic parser for Cirrus codec driver') Signed-off-by:
Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
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Nicholas Bellinger authored
commit e5419865 upstream. This patch fixes a regression introduced with the following commit in v4.0-rc1 code, where a iscsit_start_kthreads() failure triggers a NULL pointer dereference OOPs: commit 88dcd2da Author: Nicholas Bellinger <nab@linux-iscsi.org> Date: Thu Feb 26 22:19:15 2015 -0800 iscsi-target: Convert iscsi_thread_set usage to kthread.h To address this bug, move iscsit_start_kthreads() immediately preceeding the transmit of last login response, before signaling a successful transition into full-feature-phase within existing iscsi_target_do_tx_login_io() logic. This ensures that no target-side resource allocation failures can occur after the final login response has been successfully sent. Also, it adds a iscsi_conn->rx_login_comp to allow the RX thread to sleep to prevent other socket related failures until the final iscsi_post_login_handler() call is able to complete. Cc: Sagi Grimberg <sagig@mellanox.com> Signed-off-by:
Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by:
Nicholas Bellinger <nab@daterainc.com> Signed-off-by:
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Roger Quadros authored
commit 9a258afa upstream. For hwmods without sysc, _init_mpu_rt_base(oh) won't be called and so _find_mpu_rt_port(oh) will return NULL thus preventing ready state check on those modules after the module is enabled. This can potentially cause a bus access error if the module is accessed before the module is ready. Fix this by unconditionally calling _init_mpu_rt_base() during hwmod _init(). Do ioremap only if we need SYSC access. Eventhough _wait_target_ready() check doesn't really need MPU RT port but just the PRCM registers, we still mandate that the hwmod must have an MPU RT port if ready state check needs to be done. Else it would mean that the module is not accessible by MPU so there is no point in waiting for target to be ready. e.g. this fixes the below DCAN bus access error on AM437x-gp-evm. [ 16.672978] ------------[ cut here ]------------ [ 16.677885] WARNING: CPU: 0 PID: 1580 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x234/0x35c() [ 16.687946] 44000000.ocp:L3 Custom Error: MASTER M2 (64-bit) TARGET L4_PER_0 (Read): Data Access in User mode during Functional access [ 16.700654] Modules linked in: xhci_hcd btwilink ti_vpfe dwc3 videobuf2_core ov2659 bluetooth v4l2_common videodev ti_am335x_adc kfifo_buf industrialio c_can_platform videobuf2_dma_contig media snd_soc_tlv320aic3x pixcir_i2c_ts c_can dc [ 16.731144] CPU: 0 PID: 1580 Comm: rpc.statd Not tainted 3.14.26-02561-gf733aa036398 #180 [ 16.739747] Backtrace: [ 16.742336] [<c0011108>] (dump_backtrace) from [<c00112a4>] (show_stack+0x18/0x1c) [ 16.750285] r6:00000093 r5:00000009 r4:eab5b8a8 r3:00000000 [ 16.756252] [<c001128c>] (show_stack) from [<c05a4418>] (dump_stack+0x20/0x28) [ 16.763870] [<c05a43f8>] (dump_stack) from [<c0037120>] (warn_slowpath_common+0x6c/0x8c) [ 16.772408] [<c00370b4>] (warn_slowpath_common) from [<c00371e4>] (warn_slowpath_fmt+0x38/0x40) [ 16.781550] r8:c05d1f90 r7:c0730844 r6:c0730448 r5:80080003 r4:ed0cd210 [ 16.788626] [<c00371b0>] (warn_slowpath_fmt) from [<c027fa94>] (l3_interrupt_handler+0x234/0x35c) [ 16.797968] r3:ed0cd480 r2:c0730508 [ 16.801747] [<c027f860>] (l3_interrupt_handler) from [<c0063758>] (handle_irq_event_percpu+0x54/0x1bc) [ 16.811533] r10:ed005600 r9:c084855b r8:0000002a r7:00000000 r6:00000000 r5:0000002a [ 16.819780] r4:ed0e6d80 [ 16.822453] [<c0063704>] (handle_irq_event_percpu) from [<c00638f0>] (handle_irq_event+0x30/0x40) [ 16.831789] r10:eb2b6938 r9:eb2b6960 r8:bf011420 r7:fa240100 r6:00000000 r5:0000002a [ 16.840052] r4:ed005600 [ 16.842744] [<c00638c0>] (handle_irq_event) from [<c00661d8>] (handle_fasteoi_irq+0x74/0x128) [ 16.851702] r4:ed005600 r3:00000000 [ 16.855479] [<c0066164>] (handle_fasteoi_irq) from [<c0063068>] (generic_handle_irq+0x28/0x38) [ 16.864523] r4:0000002a r3:c0066164 [ 16.868294] [<c0063040>] (generic_handle_irq) from [<c000ef60>] (handle_IRQ+0x38/0x8c) [ 16.876612] r4:c081c640 r3:00000202 [ 16.880380] [<c000ef28>] (handle_IRQ) from [<c00084f0>] (gic_handle_irq+0x30/0x5c) [ 16.888328] r6:eab5ba38 r5:c0804460 r4:fa24010c r3:00000100 [ 16.894303] [<c00084c0>] (gic_handle_irq) from [<c05a8d80>] (__irq_svc+0x40/0x50) [ 16.902193] Exception stack(0xeab5ba38 to 0xeab5ba80) [ 16.907499] ba20: 00000000 00000006 [ 16.916108] ba40: fa1d0000 fa1d0008 ed3d3000 eab5bab4 ed3d3460 c0842af4 bf011420 eb2b6960 [ 16.924716] ba60: eb2b6938 eab5ba8c eab5ba90 eab5ba80 bf035220 bf07702c 600f0013 ffffffff [ 16.933317] r7:eab5ba6c r6:ffffffff r5:600f0013 r4:bf07702c [ 16.939317] [<bf077000>] (c_can_plat_read_reg_aligned_to_16bit [c_can_platform]) from [<bf035220>] (c_can_get_berr_counter+0x38/0x64 [c_can]) [ 16.952696] [<bf0351e8>] (c_can_get_berr_counter [c_can]) from [<bf010294>] (can_fill_info+0x124/0x15c [can_dev]) [ 16.963480] r5:ec8c9740 r4:ed3d3000 [ 16.967253] [<bf010170>] (can_fill_info [can_dev]) from [<c0502fa8>] (rtnl_fill_ifinfo+0x58c/0x8fc) [ 16.976749] r6:ec8c9740 r5:ed3d3000 r4:eb2b6780 [ 16.981613] [<c0502a1c>] (rtnl_fill_ifinfo) from [<c0503408>] (rtnl_dump_ifinfo+0xf0/0x1dc) [ 16.990401] r10:ec8c9740 r9:00000000 r8:00000000 r7:00000000 r6:ebd4d1b4 r5:ed3d3000 [ 16.998671] r4:00000000 [ 17.001342] [<c0503318>] (rtnl_dump_ifinfo) from [<c050e6e4>] (netlink_dump+0xa8/0x1e0) [ 17.009772] r10:00000000 r9:00000000 r8:c0503318 r7:ebf3e6c0 r6:ebd4d1b4 r5:ec8c9740 [ 17.018050] r4:ebd4d000 [ 17.020714] [<c050e63c>] (netlink_dump) from [<c050ec10>] (__netlink_dump_start+0x104/0x154) [ 17.029591] r6:eab5bd34 r5:ec8c9980 r4:ebd4d000 [ 17.034454] [<c050eb0c>] (__netlink_dump_start) from [<c0505604>] (rtnetlink_rcv_msg+0x110/0x1f4) [ 17.043778] r7:00000000 r6:ec8c9980 r5:00000f40 r4:ebf3e6c0 [ 17.049743] [<c05054f4>] (rtnetlink_rcv_msg) from [<c05108e8>] (netlink_rcv_skb+0xb4/0xc8) [ 17.058449] r8:eab5bdac r7:ec8c9980 r6:c05054f4 r5:ec8c9980 r4:ebf3e6c0 [ 17.065534] [<c0510834>] (netlink_rcv_skb) from [<c0504134>] (rtnetlink_rcv+0x24/0x2c) [ 17.073854] r6:ebd4d000 r5:00000014 r4:ec8c9980 r3:c0504110 [ 17.079846] [<c0504110>] (rtnetlink_rcv) from [<c05102ac>] (netlink_unicast+0x180/0x1ec) [ 17.088363] r4:ed0c6800 r3:c0504110 [ 17.092113] [<c051012c>] (netlink_unicast) from [<c0510670>] (netlink_sendmsg+0x2ac/0x380) [ 17.100813] r10:00000000 r8:00000008 r7:ec8c9980 r6:ebd4d000 r5:eab5be70 r4:eab5bee4 [ 17.109083] [<c05103c4>] (netlink_sendmsg) from [<c04dfdb4>] (sock_sendmsg+0x90/0xb0) [ 17.117305] r10:00000000 r9:eab5a000 r8:becdda3c r7:0000000c r6:ea978400 r5:eab5be70 [ 17.125563] r4:c05103c4 [ 17.128225] [<c04dfd24>] (sock_sendmsg) from [<c04e1c28>] (SyS_sendto+0xb8/0xdc) [ 17.136001] r6:becdda5c r5:00000014 r4:ecd37040 [ 17.140876] [<c04e1b70>] (SyS_sendto) from [<c000e680>] (ret_fast_syscall+0x0/0x30) [ 17.148923] r10:00000000 r8:c000e804 r7:00000122 r6:becdda5c r5:0000000c r4:becdda5c [ 17.157169] ---[ end trace 2b71e15b38f58bad ]--- Fixes: 6423d6df ("ARM: OMAP2+: hwmod: check for module address space during init") Signed-off-by:
Roger Quadros <rogerq@ti.com> Signed-off-by:
Paul Walmsley <paul@pwsan.com> Signed-off-by:
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Herbert Xu authored
commit f898c522 upstream. This patch removes a bogus BUG_ON in the ablkcipher path that triggers when the destination buffer is different from the source buffer and is scattered. Signed-off-by:
Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:
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- 19 Aug, 2015 4 commits
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Andy Lutomirski authored
commit aa1acff3 upstream. The update_va_mapping hypercall can fail if the VA isn't present in the guest's page tables. Under certain loads, this can result in an OOPS when the target address is in unpopulated vmap space. While we're at it, add comments to help explain what's going on. This isn't a great long-term fix. This code should probably be changed to use something like set_memory_ro. Signed-off-by:
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Axel Lin authored
commit fa8173a3 upstream. The de-emphasis sampling rate selection is controlled by BIT[3:4] of PCM1681_DEEMPH_CONTROL register. Do proper left shift to set it. Signed-off-by:
Axel Lin <axel.lin@ingics.com> Acked-by:
Marek Belisko <marek.belisko@streamunlimited.com> Signed-off-by:
Mark Brown <broonie@kernel.org> Signed-off-by:
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Benjamin Randazzo authored
commit b6878d9e upstream. In drivers/md/md.c get_bitmap_file() uses kmalloc() for creating a mdu_bitmap_file_t called "file". 5769 file = kmalloc(sizeof(*file), GFP_NOIO); 5770 if (!file) 5771 return -ENOMEM; This structure is copied to user space at the end of the function. 5786 if (err == 0 && 5787 copy_to_user(arg, file, sizeof(*file))) 5788 err = -EFAULT But if bitmap is disabled only the first byte of "file" is initialized with zero, so it's possible to read some bytes (up to 4095) of kernel space memory from user space. This is an information leak. 5775 /* bitmap disabled, zero the first byte and copy out */ 5776 if (!mddev->bitmap_info.file) 5777 file->pathname[0] = '\0'; Signed-off-by:
Benjamin Randazzo <benjamin@randazzo.fr> Signed-off-by:
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David S. Miller authored
[ Upstream commit 44922150 ] If we have a series of events from userpsace, with %fprs=FPRS_FEF, like follows: ETRAP ETRAP VIS_ENTRY(fprs=0x4) VIS_EXIT RTRAP (kernel FPU restore with fpu_saved=0x4) RTRAP We will not restore the user registers that were clobbered by the FPU using kernel code in the inner-most trap. Traps allocate FPU save slots in the thread struct, and FPU using sequences save the "dirty" FPU registers only. This works at the initial trap level because all of the registers get recorded into the top-level FPU save area, and we'll return to userspace with the FPU disabled so that any FPU use by the user will take an FPU disabled trap wherein we'll load the registers back up properly. But this is not how trap returns from kernel to kernel operate. The simplest fix for this bug is to always save all FPU register state for anything other than the top-most FPU save area. Getting rid of the optimized inner-slot FPU saving code ends up making VISEntryHalf degenerate into plain VISEntry. Longer term we need to do something smarter to reinstate the partial save optimizations. Perhaps the fundament error is having trap entry and exit allocate FPU save slots and restore register state. Instead, the VISEntry et al. calls should be doing that work. This bug is about two decades old. Reported-by:
James Y Knight <jyknight@google.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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