- 26 Jan, 2016 40 commits
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Ilya Dryomov authored
commit 67645d76 upstream. There are a number of problems with revoking a "was sending" message: (1) We never make any attempt to revoke data - only kvecs contibute to con->out_skip. However, once the header (envelope) is written to the socket, our peer learns data_len and sets itself to expect at least data_len bytes to follow front or front+middle. If ceph_msg_revoke() is called while the messenger is sending message's data portion, anything we send after that call is counted by the OSD towards the now revoked message's data portion. The effects vary, the most common one is the eventual hang - higher layers get stuck waiting for the reply to the message that was sent out after ceph_msg_revoke() returned and treated by the OSD as a bunch of data bytes. This is what Matt ran into. (2) Flat out zeroing con->out_kvec_bytes worth of bytes to handle kvecs is wrong. If ceph_msg_revoke() is called before the tag is sent out or while the messenger is sending the header, we will get a connection reset, either due to a bad tag (0 is not a valid tag) or a bad header CRC, which kind of defeats the purpose of revoke. Currently the kernel client refuses to work with header CRCs disabled, but that will likely change in the future, making this even worse. (3) con->out_skip is not reset on connection reset, leading to one or more spurious connection resets if we happen to get a real one between con->out_skip is set in ceph_msg_revoke() and before it's cleared in write_partial_skip(). Fixing (1) and (3) is trivial. The idea behind fixing (2) is to never zero the tag or the header, i.e. send out tag+header regardless of when ceph_msg_revoke() is called. That way the header is always correct, no unnecessary resets are induced and revoke stands ready for disabled CRCs. Since ceph_msg_revoke() rips out con->out_msg, introduce a new "message out temp" and copy the header into it before sending. Reported-by:
Matt Conner <matt.conner@keepertech.com> Signed-off-by:
Ilya Dryomov <idryomov@gmail.com> Tested-by:
Sage Weil <sage@redhat.com> Signed-off-by:
Kamal Mostafa <kamal@canonical.com>
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Takashi Iwai authored
commit 230323da upstream. Currently ALSA timer device doesn't take the disconnection into account very well; it merely unlinks the timer device at disconnection callback but does nothing else. Because of this, when an application accessing the timer device is disconnected, it may release the resource before actually closed. In most cases, it results in a warning message indicating a leftover timer instance like: ALSA: timer xxxx is busy? But basically this is an open race. This patch tries to address it. The strategy is like other ALSA devices: namely, - Manage card's refcount at each open/close - Wake up the pending tasks at disconnection - Check the shutdown flag appropriately at each possible call Note that this patch has one ugly hack to handle the wakeup of pending tasks. It'd be cleaner to introduce a new disconnect op to snd_timer_instance ops. But since it would lead to internal ABI breakage and it eventually increase my own work when backporting to stable kernels, I took a different path to implement locally in timer.c. A cleanup patch will follow at next for 4.5 kernel. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=109431Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
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Mateusz Guzik authored
commit ddf1d398 upstream. An unprivileged user can trigger an oops on a kernel with CONFIG_CHECKPOINT_RESTORE. proc_pid_cmdline_read takes mmap_sem for reading and obtains args + env start/end values. These get sanity checked as follows: BUG_ON(arg_start > arg_end); BUG_ON(env_start > env_end); These can be changed by prctl_set_mm. Turns out also takes the semaphore for reading, effectively rendering it useless. This results in: kernel BUG at fs/proc/base.c:240! invalid opcode: 0000 [#1] SMP Modules linked in: virtio_net CPU: 0 PID: 925 Comm: a.out Not tainted 4.4.0-rc8-next-20160105dupa+ #71 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 task: ffff880077a68000 ti: ffff8800784d0000 task.ti: ffff8800784d0000 RIP: proc_pid_cmdline_read+0x520/0x530 RSP: 0018:ffff8800784d3db8 EFLAGS: 00010206 RAX: ffff880077c5b6b0 RBX: ffff8800784d3f18 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 00007f78e8857000 RDI: 0000000000000246 RBP: ffff8800784d3e40 R08: 0000000000000008 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000050 R13: 00007f78e8857800 R14: ffff88006fcef000 R15: ffff880077c5b600 FS: 00007f78e884a740(0000) GS:ffff88007b200000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 00007f78e8361770 CR3: 00000000790a5000 CR4: 00000000000006f0 Call Trace: __vfs_read+0x37/0x100 vfs_read+0x82/0x130 SyS_read+0x58/0xd0 entry_SYSCALL_64_fastpath+0x12/0x76 Code: 4c 8b 7d a8 eb e9 48 8b 9d 78 ff ff ff 4c 8b 7d 90 48 8b 03 48 39 45 a8 0f 87 f0 fe ff ff e9 d1 fe ff ff 4c 8b 7d 90 eb c6 0f 0b <0f> 0b 0f 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 RIP proc_pid_cmdline_read+0x520/0x530 ---[ end trace 97882617ae9c6818 ]--- Turns out there are instances where the code just reads aformentioned values without locking whatsoever - namely environ_read and get_cmdline. Interestingly these functions look quite resilient against bogus values, but I don't believe this should be relied upon. The first patch gets rid of the oops bug by grabbing mmap_sem for writing. The second patch is optional and puts locking around aformentioned consumers for safety. Consumers of other fields don't seem to benefit from similar treatment and are left untouched. This patch (of 2): The code was taking the semaphore for reading, which does not protect against readers nor concurrent modifications. The problem could cause a sanity checks to fail in procfs's cmdline reader, resulting in an OOPS. Note that some functions perform an unlocked read of various mm fields, but they seem to be fine despite possible modificaton. Signed-off-by:
Mateusz Guzik <mguzik@redhat.com> Acked-by:
Cyrill Gorcunov <gorcunov@openvz.org> Cc: Alexey Dobriyan <adobriyan@gmail.com> Cc: Jarod Wilson <jarod@redhat.com> Cc: Jan Stancek <jstancek@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Anshuman Khandual <anshuman.linux@gmail.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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Junil Lee authored
commit c102f07c upstream. record_obj() in migrate_zspage() does not preserve handle's HANDLE_PIN_BIT, set by find_aloced_obj()->trypin_tag(), and implicitly (accidentally) un-pins the handle, while migrate_zspage() still performs an explicit unpin_tag() on the that handle. This additional explicit unpin_tag() introduces a race condition with zs_free(), which can pin that handle by this time, so the handle becomes un-pinned. Schematically, it goes like this: CPU0 CPU1 migrate_zspage find_alloced_obj trypin_tag set HANDLE_PIN_BIT zs_free() pin_tag() obj_malloc() -- new object, no tag record_obj() -- remove HANDLE_PIN_BIT set HANDLE_PIN_BIT unpin_tag() -- remove zs_free's HANDLE_PIN_BIT The race condition may result in a NULL pointer dereference: Unable to handle kernel NULL pointer dereference at virtual address 00000000 CPU: 0 PID: 19001 Comm: CookieMonsterCl Tainted: PC is at get_zspage_mapping+0x0/0x24 LR is at obj_free.isra.22+0x64/0x128 Call trace: get_zspage_mapping+0x0/0x24 zs_free+0x88/0x114 zram_free_page+0x64/0xcc zram_slot_free_notify+0x90/0x108 swap_entry_free+0x278/0x294 free_swap_and_cache+0x38/0x11c unmap_single_vma+0x480/0x5c8 unmap_vmas+0x44/0x60 exit_mmap+0x50/0x110 mmput+0x58/0xe0 do_exit+0x320/0x8dc do_group_exit+0x44/0xa8 get_signal+0x538/0x580 do_signal+0x98/0x4b8 do_notify_resume+0x14/0x5c This patch keeps the lock bit in migration path and update value atomically. Signed-off-by:
Junil Lee <junil0814.lee@lge.com> Signed-off-by:
Minchan Kim <minchan@kernel.org> Acked-by:
Vlastimil Babka <vbabka@suse.cz> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by:
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Takashi Iwai authored
commit 991f86d7 upstream. As HD-audio driver does deferred probe internally via workqueue, the driver might go into the mixed state doing both probe and remove when the module gets unloaded during the probe work. This eventually triggers an Oops, unsurprisingly. For avoiding this race, we just need to flush the pending probe work explicitly before actually starting the resource release. Bugzilla: https://bugzilla.opensuse.org/show_bug.cgi?id=960710Signed-off-by:
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Herbert Xu authored
commit 202736d9 upstream. We mark the end of the SG list in sendmsg and sendpage and unmark it on the next send call. Unfortunately the unmarking in sendmsg is off-by-one, leading to an SG list that is too short. Fixes: 0f477b65 ("crypto: algif - Mark sgl end at the end of data") Signed-off-by:
Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:
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Nicholas Bellinger authored
commit 26a99c19 upstream. This patch is a iscsi-target specific bug-fix for a dead-lock that can occur during explicit struct se_node_acl->acl_group se_session deletion via configfs rmdir(2), when iscsi-target time2retain timer is still active. It changes iscsi-target to obtain se_portal_group->session_lock internally using spin_in_locked() to check for the specific se_node_acl configfs shutdown rmdir(2) case. Note this patch is intended for stable, and the subsequent v4.5-rc patch converts target_core_tpg.c to use proper se_sess->sess_kref reference counting for both se_node_acl deletion + se_node_acl->queue_depth se_session restart. Reported-by:
: Sagi Grimberg <sagig@mellanox.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Andy Grover <agrover@redhat.com> Cc: Mike Christie <michaelc@cs.wisc.edu> Signed-off-by:
Nicholas Bellinger <nab@linux-iscsi.org> Signed-off-by:
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Filipe Manana authored
commit c2d6cb16 upstream. While running a stress test I ran into a deadlock when running the delayed iputs at transaction time, which produced the following report and trace: [ 886.399989] ============================================= [ 886.400871] [ INFO: possible recursive locking detected ] [ 886.401663] 4.4.0-rc6-btrfs-next-18+ #1 Not tainted [ 886.402384] --------------------------------------------- [ 886.403182] fio/8277 is trying to acquire lock: [ 886.403568] (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs] [ 886.403568] [ 886.403568] but task is already holding lock: [ 886.403568] (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs] [ 886.403568] [ 886.403568] other info that might help us debug this: [ 886.403568] Possible unsafe locking scenario: [ 886.403568] [ 886.403568] CPU0 [ 886.403568] ---- [ 886.403568] lock(&fs_info->delayed_iput_sem); [ 886.403568] lock(&fs_info->delayed_iput_sem); [ 886.403568] [ 886.403568] *** DEADLOCK *** [ 886.403568] [ 886.403568] May be due to missing lock nesting notation [ 886.403568] [ 886.403568] 3 locks held by fio/8277: [ 886.403568] #0: (sb_writers#11){.+.+.+}, at: [<ffffffff81174c4c>] __sb_start_write+0x5f/0xb0 [ 886.403568] #1: (&sb->s_type->i_mutex_key#15){+.+.+.}, at: [<ffffffffa054620d>] btrfs_file_write_iter+0x73/0x408 [btrfs] [ 886.403568] #2: (&fs_info->delayed_iput_sem){++++..}, at: [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs] [ 886.403568] [ 886.403568] stack backtrace: [ 886.403568] CPU: 6 PID: 8277 Comm: fio Not tainted 4.4.0-rc6-btrfs-next-18+ #1 [ 886.403568] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014 [ 886.403568] 0000000000000000 ffff88009f80f770 ffffffff8125d4fd ffffffff82af1fc0 [ 886.403568] ffff88009f80f830 ffffffff8108e5f9 0000000200000000 ffff88009fd92290 [ 886.403568] 0000000000000000 ffffffff82af1fc0 ffffffff829cfb01 00042b216d008804 [ 886.403568] Call Trace: [ 886.403568] [<ffffffff8125d4fd>] dump_stack+0x4e/0x79 [ 886.403568] [<ffffffff8108e5f9>] __lock_acquire+0xd42/0xf0b [ 886.403568] [<ffffffff810c22db>] ? __module_address+0xdf/0x108 [ 886.403568] [<ffffffff8108eb77>] lock_acquire+0x10d/0x194 [ 886.403568] [<ffffffff8108eb77>] ? lock_acquire+0x10d/0x194 [ 886.403568] [<ffffffffa0538823>] ? btrfs_run_delayed_iputs+0x36/0xbf [btrfs] [ 886.489542] [<ffffffff8148556b>] down_read+0x3e/0x4d [ 886.489542] [<ffffffffa0538823>] ? btrfs_run_delayed_iputs+0x36/0xbf [btrfs] [ 886.489542] [<ffffffffa0538823>] btrfs_run_delayed_iputs+0x36/0xbf [btrfs] [ 886.489542] [<ffffffffa0533953>] btrfs_commit_transaction+0x8f5/0x96e [btrfs] [ 886.489542] [<ffffffffa0521d7a>] flush_space+0x435/0x44a [btrfs] [ 886.489542] [<ffffffffa052218b>] ? reserve_metadata_bytes+0x26a/0x384 [btrfs] [ 886.489542] [<ffffffffa05221ae>] reserve_metadata_bytes+0x28d/0x384 [btrfs] [ 886.489542] [<ffffffffa052256c>] ? btrfs_block_rsv_refill+0x58/0x96 [btrfs] [ 886.489542] [<ffffffffa0522584>] btrfs_block_rsv_refill+0x70/0x96 [btrfs] [ 886.489542] [<ffffffffa053d747>] btrfs_evict_inode+0x394/0x55a [btrfs] [ 886.489542] [<ffffffff81188e31>] evict+0xa7/0x15c [ 886.489542] [<ffffffff81189878>] iput+0x1d3/0x266 [ 886.489542] [<ffffffffa053887c>] btrfs_run_delayed_iputs+0x8f/0xbf [btrfs] [ 886.489542] [<ffffffffa0533953>] btrfs_commit_transaction+0x8f5/0x96e [btrfs] [ 886.489542] [<ffffffff81085096>] ? signal_pending_state+0x31/0x31 [ 886.489542] [<ffffffffa0521191>] btrfs_alloc_data_chunk_ondemand+0x1d7/0x288 [btrfs] [ 886.489542] [<ffffffffa0521282>] btrfs_check_data_free_space+0x40/0x59 [btrfs] [ 886.489542] [<ffffffffa05228f5>] btrfs_delalloc_reserve_space+0x1e/0x4e [btrfs] [ 886.489542] [<ffffffffa053620a>] btrfs_direct_IO+0x10c/0x27e [btrfs] [ 886.489542] [<ffffffff8111d9a1>] generic_file_direct_write+0xb3/0x128 [ 886.489542] [<ffffffffa05463c3>] btrfs_file_write_iter+0x229/0x408 [btrfs] [ 886.489542] [<ffffffff8108ae38>] ? __lock_is_held+0x38/0x50 [ 886.489542] [<ffffffff8117279e>] __vfs_write+0x7c/0xa5 [ 886.489542] [<ffffffff81172cda>] vfs_write+0xa0/0xe4 [ 886.489542] [<ffffffff811734cc>] SyS_write+0x50/0x7e [ 886.489542] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 1081.852335] INFO: task fio:8244 blocked for more than 120 seconds. [ 1081.854348] Not tainted 4.4.0-rc6-btrfs-next-18+ #1 [ 1081.857560] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1081.863227] fio D ffff880213f9bb28 0 8244 8240 0x00000000 [ 1081.868719] ffff880213f9bb28 00ffffff810fc6b0 ffffffff0000000a ffff88023ed55240 [ 1081.872499] ffff880206b5d400 ffff880213f9c000 ffff88020a4d5318 ffff880206b5d400 [ 1081.876834] ffffffff00000001 ffff880206b5d400 ffff880213f9bb40 ffffffff81482ba4 [ 1081.880782] Call Trace: [ 1081.881793] [<ffffffff81482ba4>] schedule+0x7f/0x97 [ 1081.883340] [<ffffffff81485eb5>] rwsem_down_write_failed+0x2d5/0x325 [ 1081.895525] [<ffffffff8108d48d>] ? trace_hardirqs_on_caller+0x16/0x1ab [ 1081.897419] [<ffffffff81269723>] call_rwsem_down_write_failed+0x13/0x20 [ 1081.899251] [<ffffffff81269723>] ? call_rwsem_down_write_failed+0x13/0x20 [ 1081.901063] [<ffffffff81089fae>] ? __down_write_nested.isra.0+0x1f/0x21 [ 1081.902365] [<ffffffff814855bd>] down_write+0x43/0x57 [ 1081.903846] [<ffffffffa05211b0>] ? btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs] [ 1081.906078] [<ffffffffa05211b0>] btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs] [ 1081.908846] [<ffffffff8108d461>] ? mark_held_locks+0x56/0x6c [ 1081.910409] [<ffffffffa0521282>] btrfs_check_data_free_space+0x40/0x59 [btrfs] [ 1081.912482] [<ffffffffa05228f5>] btrfs_delalloc_reserve_space+0x1e/0x4e [btrfs] [ 1081.914597] [<ffffffffa053620a>] btrfs_direct_IO+0x10c/0x27e [btrfs] [ 1081.919037] [<ffffffff8111d9a1>] generic_file_direct_write+0xb3/0x128 [ 1081.920754] [<ffffffffa05463c3>] btrfs_file_write_iter+0x229/0x408 [btrfs] [ 1081.922496] [<ffffffff8108ae38>] ? __lock_is_held+0x38/0x50 [ 1081.923922] [<ffffffff8117279e>] __vfs_write+0x7c/0xa5 [ 1081.925275] [<ffffffff81172cda>] vfs_write+0xa0/0xe4 [ 1081.926584] [<ffffffff811734cc>] SyS_write+0x50/0x7e [ 1081.927968] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f [ 1081.985293] INFO: lockdep is turned off. [ 1081.986132] INFO: task fio:8249 blocked for more than 120 seconds. [ 1081.987434] Not tainted 4.4.0-rc6-btrfs-next-18+ #1 [ 1081.988534] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 1081.990147] fio D ffff880218febbb8 0 8249 8240 0x00000000 [ 1081.991626] ffff880218febbb8 00ffffff81486b8e ffff88020000000b ffff88023ed75240 [ 1081.993258] ffff8802120a9a00 ffff880218fec000 ffff88020a4d5318 ffff8802120a9a00 [ 1081.994850] ffffffff00000001 ffff8802120a9a00 ffff880218febbd0 ffffffff81482ba4 [ 1081.996485] Call Trace: [ 1081.997037] [<ffffffff81482ba4>] schedule+0x7f/0x97 [ 1081.998017] [<ffffffff81485eb5>] rwsem_down_write_failed+0x2d5/0x325 [ 1081.999241] [<ffffffff810852a5>] ? finish_wait+0x6d/0x76 [ 1082.000306] [<ffffffff81269723>] call_rwsem_down_write_failed+0x13/0x20 [ 1082.001533] [<ffffffff81269723>] ? call_rwsem_down_write_failed+0x13/0x20 [ 1082.002776] [<ffffffff81089fae>] ? __down_write_nested.isra.0+0x1f/0x21 [ 1082.003995] [<ffffffff814855bd>] down_write+0x43/0x57 [ 1082.005000] [<ffffffffa05211b0>] ? btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs] [ 1082.007403] [<ffffffffa05211b0>] btrfs_alloc_data_chunk_ondemand+0x1f6/0x288 [btrfs] [ 1082.008988] [<ffffffffa0545064>] btrfs_fallocate+0x7c1/0xc2f [btrfs] [ 1082.010193] [<ffffffff8108a1ba>] ? percpu_down_read+0x4e/0x77 [ 1082.011280] [<ffffffff81174c4c>] ? __sb_start_write+0x5f/0xb0 [ 1082.012265] [<ffffffff81174c4c>] ? __sb_start_write+0x5f/0xb0 [ 1082.013021] [<ffffffff811712e4>] vfs_fallocate+0x170/0x1ff [ 1082.013738] [<ffffffff81181ebb>] ioctl_preallocate+0x89/0x9b [ 1082.014778] [<ffffffff811822d7>] do_vfs_ioctl+0x40a/0x4ea [ 1082.015778] [<ffffffff81176ea7>] ? SYSC_newfstat+0x25/0x2e [ 1082.016806] [<ffffffff8118b4de>] ? __fget_light+0x4d/0x71 [ 1082.017789] [<ffffffff8118240e>] SyS_ioctl+0x57/0x79 [ 1082.018706] [<ffffffff814872d7>] entry_SYSCALL_64_fastpath+0x12/0x6f This happens because we can recursively acquire the semaphore fs_info->delayed_iput_sem when attempting to allocate space to satisfy a file write request as shown in the first trace above - when committing a transaction we acquire (down_read) the semaphore before running the delayed iputs, and when running a delayed iput() we can end up calling an inode's eviction handler, which in turn commits another transaction and attempts to acquire (down_read) again the semaphore to run more delayed iput operations. This results in a deadlock because if a task acquires multiple times a semaphore it should invoke down_read_nested() with a different lockdep class for each level of recursion. Fix this by simplifying the implementation and use a mutex instead that is acquired by the cleaner kthread before it runs the delayed iputs instead of always acquiring a semaphore before delayed references are run from anywhere. Fixes: d7c15171 (btrfs: Fix NO_SPACE bug caused by delayed-iput) Signed-off-by:
Filipe Manana <fdmanana@suse.com> Signed-off-by:
Chris Mason <clm@fb.com> Signed-off-by:
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Josh Boyer authored
commit edde316a upstream. One of the newest ideapad models also lacks a physical hw rfkill switch, and trying to read the hw rfkill switch through the ideapad module causes it to always reported blocking breaking wifi. Fix it by adding this model to the DMI list. BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1286293Signed-off-by:
Josh Boyer <jwboyer@fedoraproject.org> Signed-off-by:
Darren Hart <dvhart@linux.intel.com> Signed-off-by:
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Bart Van Assche authored
commit 4bfdf635 upstream. ib_send_cm_drep() calls cm_enter_timewait() while holding a spinlock that can be locked from inside an interrupt handler. Hence do not enable interrupts inside cm_enter_timewait() if called with interrupts disabled. This patch fixes e.g. the following deadlock: Acked-by:
Erez Shitrit <erezsh@mellanox.com> ================================= [ INFO: inconsistent lock state ] 4.4.0-rc7+ #1 Tainted: G E --------------------------------- inconsistent {HARDIRQ-ON-W} -> {IN-HARDIRQ-W} usage. swapper/8/0 [HC1[1]:SC0[0]:HE0:SE1] takes: (&(&cm_id_priv->lock)->rlock){?.+...}, at: [<ffffffffa036eec4>] cm_establish+0x 74/0x1b0 [ib_cm] {HARDIRQ-ON-W} state was registered at: [<ffffffff810a3c11>] mark_held_locks+0x71/0x90 [<ffffffff810a3e87>] trace_hardirqs_on_caller+0xa7/0x1c0 [<ffffffff810a3fad>] trace_hardirqs_on+0xd/0x10 [<ffffffff8151c40b>] _raw_spin_unlock_irq+0x2b/0x40 [<ffffffffa036ea8e>] cm_enter_timewait+0xae/0x100 [ib_cm] [<ffffffffa036ff76>] ib_send_cm_drep+0xb6/0x190 [ib_cm] [<ffffffffa052ed08>] srp_cm_handler+0x128/0x1a0 [ib_srp] [<ffffffffa0370340>] cm_process_work+0x20/0xf0 [ib_cm] [<ffffffffa0371335>] cm_dreq_handler+0x135/0x2c0 [ib_cm] [<ffffffffa03733c5>] cm_work_handler+0x75/0xd0 [ib_cm] [<ffffffff8107184d>] process_one_work+0x1bd/0x460 [<ffffffff81073148>] worker_thread+0x118/0x420 [<ffffffff81078454>] kthread+0xe4/0x100 [<ffffffff8151cbbf>] ret_from_fork+0x3f/0x70 irq event stamp: 1672286 hardirqs last enabled at (1672283): [<ffffffff81408ec0>] poll_idle+0x10/0x80 hardirqs last disabled at (1672284): [<ffffffff8151d304>] common_interrupt+0x84/0x89 softirqs last enabled at (1672286): [<ffffffff8105b4dc>] _local_bh_enable+0x1c/0x50 softirqs last disabled at (1672285): [<ffffffff8105b697>] irq_enter+0x47/0x70 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&cm_id_priv->lock)->rlock); <Interrupt> lock(&(&cm_id_priv->lock)->rlock); *** DEADLOCK *** no locks held by swapper/8/0. stack backtrace: CPU: 8 PID: 0 Comm: swapper/8 Tainted: G E 4.4.0-rc7+ #1 Hardware name: Dell Inc. PowerEdge R430/03XKDV, BIOS 1.0.2 11/17/2014 ffff88045af5e950 ffff88046e503a88 ffffffff81251c1b 0000000000000007 0000000000000006 0000000000000003 ffff88045af5ddc0 ffff88046e503ad8 ffffffff810a32f4 0000000000000000 0000000000000000 0000000000000001 Call Trace: <IRQ> [<ffffffff81251c1b>] dump_stack+0x4f/0x74 [<ffffffff810a32f4>] print_usage_bug+0x184/0x190 [<ffffffff810a36e2>] mark_lock_irq+0xf2/0x290 [<ffffffff810a3995>] mark_lock+0x115/0x1b0 [<ffffffff810a3b8c>] mark_irqflags+0x15c/0x170 [<ffffffff810a4fef>] __lock_acquire+0x1ef/0x560 [<ffffffff810a53c2>] lock_acquire+0x62/0x80 [<ffffffff8151bd33>] _raw_spin_lock_irqsave+0x43/0x60 [<ffffffffa036eec4>] cm_establish+0x74/0x1b0 [ib_cm] [<ffffffffa036f031>] ib_cm_notify+0x31/0x100 [ib_cm] [<ffffffffa0637f24>] srpt_qp_event+0x54/0xd0 [ib_srpt] [<ffffffffa0196052>] mlx4_ib_qp_event+0x72/0xc0 [mlx4_ib] [<ffffffffa00775b9>] mlx4_qp_event+0x69/0xd0 [mlx4_core] [<ffffffffa006000e>] mlx4_eq_int+0x51e/0xd50 [mlx4_core] [<ffffffffa006084f>] mlx4_msi_x_interrupt+0xf/0x20 [mlx4_core] [<ffffffff810b67b0>] handle_irq_event_percpu+0x40/0x110 [<ffffffff810b68bf>] handle_irq_event+0x3f/0x70 [<ffffffff810ba7f9>] handle_edge_irq+0x79/0x120 [<ffffffff81007f3d>] handle_irq+0x5d/0x130 [<ffffffff810071fd>] do_IRQ+0x6d/0x130 [<ffffffff8151d309>] common_interrupt+0x89/0x89 <EOI> [<ffffffff8140895f>] cpuidle_enter_state+0xcf/0x200 [<ffffffff81408aa2>] cpuidle_enter+0x12/0x20 [<ffffffff810990d6>] call_cpuidle+0x36/0x60 [<ffffffff81099163>] cpuidle_idle_call+0x63/0x110 [<ffffffff8109930a>] cpu_idle_loop+0xfa/0x130 [<ffffffff8109934e>] cpu_startup_entry+0xe/0x10 [<ffffffff8103c443>] start_secondary+0x83/0x90 Fixes: commit be4b4993 ("IB/cm: Do not queue work to a device that's going away") Signed-off-by:
Bart Van Assche <bart.vanassche@sandisk.com> Cc: Erez Shitrit <erezsh@mellanox.com> Signed-off-by:
Doug Ledford <dledford@redhat.com> Signed-off-by:
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Leon Romanovsky authored
commit 9f177686 upstream. Maximum number of EQE capacity per CQ was mistakenly exposed as CQE. Fix that. Fixes: 938fe83c ("net/mlx5_core: New device capabilities handling") Signed-off-by:
Leon Romanovsky <leonro@mellanox.com> Reviewed-by:
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Vinit Agnihotri authored
commit fbbeb863 upstream. The current code is problematic when the QP creation and ipoib is used to support NFS and NFS desires to do IO for paging purposes. In that case, the GFP_KERNEL allocation in qib_qp.c causes a deadlock in tight memory situations. This fix adds support to create queue pair with GFP_NOIO flag for connected mode only to cleanly fail the create queue pair in those situations. Reviewed-by:
Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by:
Vinit Agnihotri <vinit.abhay.agnihotri@intel.com> Signed-off-by:
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Mike Marciniszyn authored
commit 09dc9cd6 upstream. The code produces the following trace: [1750924.419007] general protection fault: 0000 [#3] SMP [1750924.420364] Modules linked in: nfnetlink autofs4 rpcsec_gss_krb5 nfsv4 dcdbas rfcomm bnep bluetooth nfsd auth_rpcgss nfs_acl dm_multipath nfs lockd scsi_dh sunrpc fscache radeon ttm drm_kms_helper drm serio_raw parport_pc ppdev i2c_algo_bit lpc_ich ipmi_si ib_mthca ib_qib dca lp parport ib_ipoib mac_hid ib_cm i3000_edac ib_sa ib_uverbs edac_core ib_umad ib_mad ib_core ib_addr tg3 ptp dm_mirror dm_region_hash dm_log psmouse pps_core [1750924.420364] CPU: 1 PID: 8401 Comm: python Tainted: G D 3.13.0-39-generic #66-Ubuntu [1750924.420364] Hardware name: Dell Computer Corporation PowerEdge 860/0XM089, BIOS A04 07/24/2007 [1750924.420364] task: ffff8800366a9800 ti: ffff88007af1c000 task.ti: ffff88007af1c000 [1750924.420364] RIP: 0010:[<ffffffffa0131d51>] [<ffffffffa0131d51>] qib_mcast_qp_free+0x11/0x50 [ib_qib] [1750924.420364] RSP: 0018:ffff88007af1dd70 EFLAGS: 00010246 [1750924.420364] RAX: 0000000000000001 RBX: ffff88007b822688 RCX: 000000000000000f [1750924.420364] RDX: ffff88007b822688 RSI: ffff8800366c15a0 RDI: 6764697200000000 [1750924.420364] RBP: ffff88007af1dd78 R08: 0000000000000001 R09: 0000000000000000 [1750924.420364] R10: 0000000000000011 R11: 0000000000000246 R12: ffff88007baa1d98 [1750924.420364] R13: ffff88003ecab000 R14: ffff88007b822660 R15: 0000000000000000 [1750924.420364] FS: 00007ffff7fd8740(0000) GS:ffff88007fc80000(0000) knlGS:0000000000000000 [1750924.420364] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1750924.420364] CR2: 00007ffff597c750 CR3: 000000006860b000 CR4: 00000000000007e0 [1750924.420364] Stack: [1750924.420364] ffff88007b822688 ffff88007af1ddf0 ffffffffa0132429 000000007af1de20 [1750924.420364] ffff88007baa1dc8 ffff88007baa0000 ffff88007af1de70 ffffffffa00cb313 [1750924.420364] 00007fffffffde88 0000000000000000 0000000000000008 ffff88003ecab000 [1750924.420364] Call Trace: [1750924.420364] [<ffffffffa0132429>] qib_multicast_detach+0x1e9/0x350 [ib_qib] [1750924.568035] [<ffffffffa00cb313>] ? ib_uverbs_modify_qp+0x323/0x3d0 [ib_uverbs] [1750924.568035] [<ffffffffa0092d61>] ib_detach_mcast+0x31/0x50 [ib_core] [1750924.568035] [<ffffffffa00cc213>] ib_uverbs_detach_mcast+0x93/0x170 [ib_uverbs] [1750924.568035] [<ffffffffa00c61f6>] ib_uverbs_write+0xc6/0x2c0 [ib_uverbs] [1750924.568035] [<ffffffff81312e68>] ? apparmor_file_permission+0x18/0x20 [1750924.568035] [<ffffffff812d4cd3>] ? security_file_permission+0x23/0xa0 [1750924.568035] [<ffffffff811bd214>] vfs_write+0xb4/0x1f0 [1750924.568035] [<ffffffff811bdc49>] SyS_write+0x49/0xa0 [1750924.568035] [<ffffffff8172f7ed>] system_call_fastpath+0x1a/0x1f [1750924.568035] Code: 66 2e 0f 1f 84 00 00 00 00 00 31 c0 5d c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb 48 8b 7f 10 <f0> ff 8f 40 01 00 00 74 0e 48 89 df e8 8e f8 06 e1 5b 5d c3 0f [1750924.568035] RIP [<ffffffffa0131d51>] qib_mcast_qp_free+0x11/0x50 [ib_qib] [1750924.568035] RSP <ffff88007af1dd70> [1750924.650439] ---[ end trace 73d5d4b3f8ad4851 ] The fix is to note the qib_mcast_qp that was found. If none is found, then return EINVAL indicating the error. Reviewed-by:
Dennis Dalessandro <dennis.dalessandro@intel.com> Reported-by:
Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by:
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Jean Delvare authored
commit fd7f6727 upstream. I don't think it makes sense for a module to have a soft dependency on itself. This seems quite cyclic by nature and I can't see what purpose it could serve. OTOH libcrc32c calls crypto_alloc_shash("crc32c", 0, 0) so it pretty much assumes that some incarnation of the "crc32c" hash algorithm has been loaded. Therefore it makes sense to have the soft dependency there (as crc-t10dif does.) Cc: Tim Chen <tim.c.chen@linux.intel.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by:
Jean Delvare <jdelvare@suse.de> Signed-off-by:
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Herbert Xu authored
commit 4f0414e5 upstream. We need to load the TX SG list in sendmsg(2) after waiting for incoming data, not before. Reported-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
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Dave Chinner authored
commit 85bec546 upstream. Recently I've been seeing xfs/051 fail on 1k block size filesystems. Trying to trace the events during the test lead to the problem going away, indicating that it was a race condition that lead to this ASSERT failure: XFS: Assertion failed: atomic_read(&pag->pag_ref) == 0, file: fs/xfs/xfs_mount.c, line: 156 ..... [<ffffffff814e1257>] xfs_free_perag+0x87/0xb0 [<ffffffff814e21b9>] xfs_mountfs+0x4d9/0x900 [<ffffffff814e5dff>] xfs_fs_fill_super+0x3bf/0x4d0 [<ffffffff811d8800>] mount_bdev+0x180/0x1b0 [<ffffffff814e3ff5>] xfs_fs_mount+0x15/0x20 [<ffffffff811d90a8>] mount_fs+0x38/0x170 [<ffffffff811f4347>] vfs_kern_mount+0x67/0x120 [<ffffffff811f7018>] do_mount+0x218/0xd60 [<ffffffff811f7e5b>] SyS_mount+0x8b/0xd0 When I finally caught it with tracing enabled, I saw that AG 2 had an elevated reference count and a buffer was responsible for it. I tracked down the specific buffer, and found that it was missing the final reference count release that would put it back on the LRU and hence be found by xfs_wait_buftarg() calls in the log mount failure handling. The last four traces for the buffer before the assert were (trimmed for relevance) kworker/0:1-5259 xfs_buf_iodone: hold 2 lock 0 flags ASYNC kworker/0:1-5259 xfs_buf_ioerror: hold 2 lock 0 error -5 mount-7163 xfs_buf_lock_done: hold 2 lock 0 flags ASYNC mount-7163 xfs_buf_unlock: hold 2 lock 1 flags ASYNC This is an async write that is completing, so there's nobody waiting for it directly. Hence we call xfs_buf_relse() once all the processing is complete. That does: static inline void xfs_buf_relse(xfs_buf_t *bp) { xfs_buf_unlock(bp); xfs_buf_rele(bp); } Now, it's clear that mount is waiting on the buffer lock, and that it has been released by xfs_buf_relse() and gained by mount. This is expected, because at this point the mount process is in xfs_buf_delwri_submit() waiting for all the IO it submitted to complete. The mount process, however, is waiting on the lock for the buffer because it is in xfs_buf_delwri_submit(). This waits for IO completion, but it doesn't wait for the buffer reference owned by the IO to go away. The mount process collects all the completions, fails the log recovery, and the higher level code then calls xfs_wait_buftarg() to free all the remaining buffers in the filesystem. The issue is that on unlocking the buffer, the scheduler has decided that the mount process has higher priority than the the kworker thread that is running the IO completion, and so immediately switched contexts to the mount process from the semaphore unlock code, hence preventing the kworker thread from finishing the IO completion and releasing the IO reference to the buffer. Hence by the time that xfs_wait_buftarg() is run, the buffer still has an active reference and so isn't on the LRU list that the function walks to free the remaining buffers. Hence we miss that buffer and continue onwards to tear down the mount structures, at which time we get find a stray reference count on the perag structure. On a non-debug kernel, this will be ignored and the structure torn down and freed. Hence when the kworker thread is then rescheduled and the buffer released and freed, it will access a freed perag structure. The problem here is that when the log mount fails, we still need to quiesce the log to ensure that the IO workqueues have returned to idle before we run xfs_wait_buftarg(). By synchronising the workqueues, we ensure that all IO completions are fully processed, not just to the point where buffers have been unlocked. This ensures we don't end up in the situation above. Signed-off-by:
Dave Chinner <dchinner@redhat.com> Reviewed-by:
Brian Foster <bfoster@redhat.com> Signed-off-by:
Dave Chinner <david@fromorbit.com> Signed-off-by:
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Arnd Bergmann authored
commit 6c548099 upstream. During my randconfig build testing, I found that a kernel with DEBUG_AT91_UART and ARCH_BCM_63XX fails to build: arch/arm/include/debug/at91.S:18:0: error: "CONFIG_DEBUG_UART_VIRT" redefined [-Werror] It turns out that the DEBUG_UART_BCM63XX option is enabled whenever the ARCH_BCM_63XX is, and that breaks multiplatform kernels because we then end up using the UART address from BCM63XX rather than the one we actually configured (if any). This changes the BCM63XX options to only have one Kconfig option, and only enable that if the user explicitly turns it on. Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Fixes: b51312be ("ARM: BCM63XX: add low-level UART debug support") Signed-off-by:
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Takashi Iwai authored
commit c0bcdbdf upstream. When a TLV ioctl with numid zero is handled, the driver may spew a kernel warning with a stack trace at each call. The check was intended obviously only for a kernel driver, but not for a user interaction. Let's fix it. This was spotted by syzkaller fuzzer. Reported-by:
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Nicolas Boichat authored
commit 9586495d upstream. This reverts one hunk of commit ef44a1ec ("ALSA: sound/core: use memdup_user()"), which replaced a number of kmalloc followed by memcpy with memdup calls. In this case, we are copying from a struct snd_seq_port_info32 to a struct snd_seq_port_info, but the latter is 4 bytes longer than the 32-bit version, so we need to separate kmalloc and copy calls. Fixes: ef44a1ec ('ALSA: sound/core: use memdup_user()') Signed-off-by:
Nicolas Boichat <drinkcat@chromium.org> Signed-off-by:
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Nicolas Boichat authored
commit 43c54b8c upstream. This reverts one hunk of commit ef44a1ec ("ALSA: sound/core: use memdup_user()"), which replaced a number of kmalloc followed by memcpy with memdup calls. In this case, we are copying from a struct snd_pcm_hw_params32 to a struct snd_pcm_hw_params, but the latter is 4 bytes longer than the 32-bit version, so we need to separate kmalloc and copy calls. This actually leads to an out-of-bounds memory access later on in sound/soc/soc-pcm.c:soc_pcm_hw_params() (detected using KASan). Fixes: ef44a1ec ('ALSA: sound/core: use memdup_user()') Signed-off-by:
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Songjun Wu authored
commit 611dcadb upstream. When having cyclic transfers, the channel was paused when performing suspend but was not correctly resumed. Signed-off-by:
Songjun Wu <songjun.wu@atmel.com> Signed-off-by:
Ludovic Desroches <ludovic.desroches@atmel.com> Fixes: e1f7c9ee ("dmaengine: at_xdmac: creation of the atmel eXtended DMA Controller driver") Signed-off-by:
Vinod Koul <vinod.koul@intel.com> Signed-off-by:
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Takashi Iwai authored
commit 2ba1fe7a upstream. hrtimer_cancel() waits for the completion from the callback, thus it must not be called inside the callback itself. This was already a problem in the past with ALSA hrtimer driver, and the early commit [fcfdebe7: ALSA: hrtimer - Fix lock-up] tried to address it. However, the previous fix is still insufficient: it may still cause a lockup when the ALSA timer instance reprograms itself in its callback. Then it invokes the start function even in snd_timer_interrupt() that is called in hrtimer callback itself, results in a CPU stall. This is no hypothetical problem but actually triggered by syzkaller fuzzer. This patch tries to fix the issue again. Now we call hrtimer_try_to_cancel() at both start and stop functions so that it won't fall into a deadlock, yet giving some chance to cancel the queue if the functions have been called outside the callback. The proper hrtimer_cancel() is called in anyway at closing, so this should be enough. Reported-and-tested-by:
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Herbert Xu authored
commit 1822793a upstream. We need to lock the child socket in skcipher_check_key as otherwise two simultaneous calls can cause the parent socket to be freed. Signed-off-by:
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Herbert Xu authored
commit ad46d7e3 upstream. We need to lock the child socket in hash_check_key as otherwise two simultaneous calls can cause the parent socket to be freed. Signed-off-by:
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Arnd Bergmann authored
commit 5b571677 upstream. The sw842 library code was merged in linux-4.1 and causes a very rare randconfig failure when CONFIG_CRC32 is not set: lib/built-in.o: In function `sw842_compress': oid_registry.c:(.text+0x12ddc): undefined reference to `crc32_be' lib/built-in.o: In function `sw842_decompress': oid_registry.c:(.text+0x137e4): undefined reference to `crc32_be' This adds an explict 'select CRC32' statement, similar to what the other users of the crc32 code have. In practice, CRC32 is always enabled anyway because over 100 other symbols select it. Signed-off-by:
Dan Streetman <ddstreet@ieee.org> Signed-off-by:
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Herbert Xu authored
commit a6a48c56 upstream. This patch forbids the calling of bind(2) when there are child sockets created by accept(2) in existence, even if they are created on the nokey path. This is needed as those child sockets have references to the tfm object which bind(2) will destroy. Signed-off-by:
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Herbert Xu authored
commit d7b65aee upstream. This patch removes the custom release parent function as the generic af_alg_release_parent now works for nokey sockets too. Signed-off-by:
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Herbert Xu authored
commit f1d84af1 upstream. This patch removes the custom release parent function as the generic af_alg_release_parent now works for nokey sockets too. Signed-off-by:
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Herbert Xu authored
commit 6a935170 upstream. This patch allows af_alg_release_parent to be called even for nokey sockets. Signed-off-by:
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Herbert Xu authored
commit 6de62f15 upstream. Hash implementations that require a key may crash if you use them without setting a key. This patch adds the necessary checks so that if you do attempt to use them without a key that we return -ENOKEY instead of proceeding. This patch also adds a compatibility path to support old applications that do acept(2) before setkey. Signed-off-by:
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Herbert Xu authored
commit a5596d63 upstream. This patch adds a way for ahash users to determine whether a key is required by a crypto_ahash transform. Signed-off-by:
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Herbert Xu authored
commit a0fa2d03 upstream. This patch adds a compatibility path to support old applications that do acept(2) before setkey. Signed-off-by:
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Herbert Xu authored
commit 37766586 upstream. This patch adds a compatibility path to support old applications that do acept(2) before setkey. Signed-off-by:
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Herbert Xu authored
commit a383292c upstream. When we fail an accept(2) call we will end up freeing the socket twice, once due to the direct sk_free call and once again through newsock. This patch fixes this by removing the sk_free call. Reported-by:
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Herbert Xu authored
commit c840ac6a upstream. Each af_alg parent socket obtained by socket(2) corresponds to a tfm object once bind(2) has succeeded. An accept(2) call on that parent socket creates a context which then uses the tfm object. Therefore as long as any child sockets created by accept(2) exist the parent socket must not be modified or freed. This patch guarantees this by using locks and a reference count on the parent socket. Any attempt to modify the parent socket will fail with EBUSY. Reported-by:
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Herbert Xu authored
commit dd504589 upstream. Some cipher implementations will crash if you try to use them without calling setkey first. This patch adds a check so that the accept(2) call will fail with -ENOKEY if setkey hasn't been done on the socket yet. Reported-by:
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Takashi Iwai authored
commit db8948e6 upstream. ASUS N550JX (PCI SSID 1043:13df) requires the same fixup for a bass speaker output pin as other N550 models. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=110001Signed-off-by:
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Tejun Heo authored
commit 8d91f8b1 upstream. @console_may_schedule tracks whether console_sem was acquired through lock or trylock. If the former, we're inside a sleepable context and console_conditional_schedule() performs cond_resched(). This allows console drivers which use console_lock for synchronization to yield while performing time-consuming operations such as scrolling. However, the actual console outputting is performed while holding irq-safe logbuf_lock, so console_unlock() clears @console_may_schedule before starting outputting lines. Also, only a few drivers call console_conditional_schedule() to begin with. This means that when a lot of lines need to be output by console_unlock(), for example on a console registration, the task doing console_unlock() may not yield for a long time on a non-preemptible kernel. If this happens with a slow console devices, for example a serial console, the outputting task may occupy the cpu for a very long time. Long enough to trigger softlockup and/or RCU stall warnings, which in turn pile more messages, sometimes enough to trigger the next cycle of warnings incapacitating the system. Fix it by making console_unlock() insert cond_resched() between lines if @console_may_schedule. Signed-off-by:
Tejun Heo <tj@kernel.org> Reported-by:
Calvin Owens <calvinowens@fb.com> Acked-by:
Jan Kara <jack@suse.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Kyle McMartin <kyle@kernel.org> Signed-off-by:
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Vitaly Kuznetsov authored
commit 7625b3a0 upstream. Commit 08d78658 ("panic: release stale console lock to always get the logbuf printed out") introduced an unwanted bad unlock balance report when panic() is called directly and not from OOPS (e.g. from out_of_memory()). The difference is that in case of OOPS we disable locks debug in oops_enter() and on direct panic call nobody does that. Fixes: 08d78658 ("panic: release stale console lock to always get the logbuf printed out") Reported-by:
kernel test robot <ying.huang@linux.intel.com> Signed-off-by:
Vitaly Kuznetsov <vkuznets@redhat.com> Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Baoquan He <bhe@redhat.com> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Xie XiuQi <xiexiuqi@huawei.com> Cc: Seth Jennings <sjenning@redhat.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Jan Kara <jack@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Signed-off-by:
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Vitaly Kuznetsov authored
commit 08d78658 upstream. In some cases we may end up killing the CPU holding the console lock while still having valuable data in logbuf. E.g. I'm observing the following: - A crash is happening on one CPU and console_unlock() is being called on some other. - console_unlock() tries to print out the buffer before releasing the lock and on slow console it takes time. - in the meanwhile crashing CPU does lots of printk()-s with valuable data (which go to the logbuf) and sends IPIs to all other CPUs. - console_unlock() finishes printing previous chunk and enables interrupts before trying to print out the rest, the CPU catches the IPI and never releases console lock. This is not the only possible case: in VT/fb subsystems we have many other console_lock()/console_unlock() users. Non-masked interrupts (or receiving NMI in case of extreme slowness) will have the same result. Getting the whole console buffer printed out on crash should be top priority. [akpm@linux-foundation.org: tweak comment text] Signed-off-by:
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