- 20 Nov, 2016 40 commits
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Joseph Qi authored
commit e6f0c6e6 upstream. Commit ac7cf246 ("ocfs2/dlm: fix race between convert and recovery") checks if lockres master has changed to identify whether new master has finished recovery or not. This will introduce a race that right after old master does umount ( means master will change), a new convert request comes. In this case, it will reset lockres state to DLM_RECOVERING and then retry convert, and then fail with lockres->l_action being set to OCFS2_AST_INVALID, which will cause inconsistent lock level between ocfs2 and dlm, and then finally BUG. Since dlm recovery will clear lock->convert_pending in dlm_move_lockres_to_recovery_list, we can use it to correctly identify the race case between convert and recovery. So fix it. Fixes: ac7cf246 ("ocfs2/dlm: fix race between convert and recovery") Link: http://lkml.kernel.org/r/57CE1569.8010704@huawei.comSigned-off-by:
Joseph Qi <joseph.qi@huawei.com> Signed-off-by:
Jun Piao <piaojun@huawei.com> Cc: Mark Fasheh <mfasheh@suse.de> Cc: Joel Becker <jlbec@evilplan.org> Cc: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Ben Hutchings <ben@decadent.org.uk>
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Ilan Tayari authored
commit b5884793 upstream. commit 1a6509d9 ("[IPSEC]: Add support for combined mode algorithms") introduced aead. The function attach_aead kmemdup()s the algorithm name during xfrm_state_construct(). However this memory is never freed. Implementation has since been slightly modified in commit ee5c2317 ("xfrm: Clone states properly on migration") without resolving this leak. This patch adds a kfree() call for the aead algorithm name. Fixes: 1a6509d9 ("[IPSEC]: Add support for combined mode algorithms") Signed-off-by:
Ilan Tayari <ilant@mellanox.com> Acked-by:
Rami Rosen <roszenrami@gmail.com> Signed-off-by:
Steffen Klassert <steffen.klassert@secunet.com> Signed-off-by:
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Guenter Roeck authored
commit 8e4b7205 upstream. Since commit acb2505d ("openrisc: fix copy_from_user()"), copy_from_user() returns the number of bytes requested, not the number of bytes not copied. Cc: Al Viro <viro@zeniv.linux.org.uk> Fixes: acb2505d ("openrisc: fix copy_from_user()") Signed-off-by:
Guenter Roeck <linux@roeck-us.net> Signed-off-by:
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Guenter Roeck authored
commit 65c0044c upstream. avr32 builds fail with: arch/avr32/kernel/built-in.o: In function `arch_ptrace': (.text+0x650): undefined reference to `___copy_from_user' arch/avr32/kernel/built-in.o:(___ksymtab+___copy_from_user+0x0): undefined reference to `___copy_from_user' kernel/built-in.o: In function `proc_doulongvec_ms_jiffies_minmax': (.text+0x5dd8): undefined reference to `___copy_from_user' kernel/built-in.o: In function `proc_dointvec_minmax_sysadmin': sysctl.c:(.text+0x6174): undefined reference to `___copy_from_user' kernel/built-in.o: In function `ptrace_has_cap': ptrace.c:(.text+0x69c0): undefined reference to `___copy_from_user' kernel/built-in.o:ptrace.c:(.text+0x6b90): more undefined references to `___copy_from_user' follow Fixes: 8630c322 ("avr32: fix copy_from_user()") Cc: Al Viro <viro@zeniv.linux.org.uk> Acked-by:
Havard Skinnemoen <hskinnemoen@gmail.com> Acked-by:
Hans-Christian Noren Egtvedt <egtvedt@samfundet.no> Signed-off-by:
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phil.turnbull@oracle.com authored
commit 8ab86c00 upstream. skb is not freed if newsk is NULL. Rework the error path so free_skb is unconditionally called on function exit. Fixes: c3ea9fa2 ("[IrDA] af_irda: IRDA_ASSERT cleanups") Signed-off-by:
Phil Turnbull <phil.turnbull@oracle.com> Signed-off-by:
David S. Miller <davem@davemloft.net> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Alex Vesker authored
commit 344bacca upstream. This fix solves a race between light flush and on the fly joins. Light flush doesn't set the device to down and unset IPOIB_OPER_UP flag, this means that if while flushing we have a MC join in progress and the QP was attached to BC MGID we can have a mismatches when re-attaching a QP to the BC MGID. The light flush would set the broadcast group to NULL causing an on the fly join to rejoin and reattach to the BC MCG as well as adding the BC MGID to the multicast list. The flush process would later on remove the BC MGID and detach it from the QP. On the next flush the BC MGID is present in the multicast list but not found when trying to detach it because of the previous double attach and single detach. [18332.714265] ------------[ cut here ]------------ [18332.717775] WARNING: CPU: 6 PID: 3767 at drivers/infiniband/core/verbs.c:280 ib_dealloc_pd+0xff/0x120 [ib_core] ... [18332.775198] Hardware name: Red Hat KVM, BIOS Bochs 01/01/2011 [18332.779411] 0000000000000000 ffff8800b50dfbb0 ffffffff813fed47 0000000000000000 [18332.784960] 0000000000000000 ffff8800b50dfbf0 ffffffff8109add1 0000011832f58300 [18332.790547] ffff880226a596c0 ffff880032482000 ffff880032482830 ffff880226a59280 [18332.796199] Call Trace: [18332.798015] [<ffffffff813fed47>] dump_stack+0x63/0x8c [18332.801831] [<ffffffff8109add1>] __warn+0xd1/0xf0 [18332.805403] [<ffffffff8109aebd>] warn_slowpath_null+0x1d/0x20 [18332.809706] [<ffffffffa025d90f>] ib_dealloc_pd+0xff/0x120 [ib_core] [18332.814384] [<ffffffffa04f3d7c>] ipoib_transport_dev_cleanup+0xfc/0x1d0 [ib_ipoib] [18332.820031] [<ffffffffa04ed648>] ipoib_ib_dev_cleanup+0x98/0x110 [ib_ipoib] [18332.825220] [<ffffffffa04e62c8>] ipoib_dev_cleanup+0x2d8/0x550 [ib_ipoib] [18332.830290] [<ffffffffa04e656f>] ipoib_uninit+0x2f/0x40 [ib_ipoib] [18332.834911] [<ffffffff81772a8a>] rollback_registered_many+0x1aa/0x2c0 [18332.839741] [<ffffffff81772bd1>] rollback_registered+0x31/0x40 [18332.844091] [<ffffffff81773b18>] unregister_netdevice_queue+0x48/0x80 [18332.848880] [<ffffffffa04f489b>] ipoib_vlan_delete+0x1fb/0x290 [ib_ipoib] [18332.853848] [<ffffffffa04df1cd>] delete_child+0x7d/0xf0 [ib_ipoib] [18332.858474] [<ffffffff81520c08>] dev_attr_store+0x18/0x30 [18332.862510] [<ffffffff8127fe4a>] sysfs_kf_write+0x3a/0x50 [18332.866349] [<ffffffff8127f4e0>] kernfs_fop_write+0x120/0x170 [18332.870471] [<ffffffff81207198>] __vfs_write+0x28/0xe0 [18332.874152] [<ffffffff810e09bf>] ? percpu_down_read+0x1f/0x50 [18332.878274] [<ffffffff81208062>] vfs_write+0xa2/0x1a0 [18332.881896] [<ffffffff812093a6>] SyS_write+0x46/0xa0 [18332.885632] [<ffffffff810039b7>] do_syscall_64+0x57/0xb0 [18332.889709] [<ffffffff81883321>] entry_SYSCALL64_slow_path+0x25/0x25 [18332.894727] ---[ end trace 09ebbe31f831ef17 ]--- Fixes: ee1e2c82 ("IPoIB: Refresh paths instead of flushing them on SM change events") Signed-off-by:
Alex Vesker <valex@mellanox.com> Signed-off-by:
Leon Romanovsky <leon@kernel.org> Signed-off-by:
Doug Ledford <dledford@redhat.com> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Alan Stern authored
commit 08c5cd37 upstream. Some full-speed mceusb infrared transceivers contain invalid endpoint descriptors for their interrupt endpoints, with bInterval set to 0. In the past they have worked out okay with the mceusb driver, because the driver sets the bInterval field in the descriptor to 1, overwriting whatever value may have been there before. However, this approach was never sanctioned by the USB core, and in fact it does not work with xHCI controllers, because they use the bInterval value that was present when the configuration was installed. Currently usbcore uses 32 ms as the default interval if the value in the endpoint descriptor is invalid. It turns out that these IR transceivers don't work properly unless the interval is set to 10 ms or below. To work around this mceusb problem, this patch changes the endpoint-descriptor parsing routine, making the default interval value be 10 ms rather than 32 ms. Signed-off-by:
Alan Stern <stern@rowland.harvard.edu> Tested-by:
Wade Berrier <wberrier@gmail.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by:
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Al Viro authored
commit 8630c322 upstream. really ugly, but apparently avr32 compilers turns access_ok() into something so bad that they want it in assembler. Left that way, zeroing added in inline wrapper. Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Al Viro authored
commit e98b9e37 upstream. Signed-off-by:
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Al Viro authored
commit d0cf3851 upstream. Signed-off-by:
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Al Viro authored
commit c90a3bc5 upstream. Signed-off-by:
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Al Viro authored
commit 8f035983 upstream. Signed-off-by:
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Al Viro authored
commit 917400ce upstream. Acked-by:
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Al Viro authored
commit 6e050503 upstream. Signed-off-by:
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Al Viro authored
commit c6852389 upstream. It could be done in exception-handling bits in __get_user_b() et.al., but the surgery involved would take more knowledge of sh64 details than I have or _want_ to have. Signed-off-by:
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Al Viro authored
commit b615e3c7 upstream. Signed-off-by:
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Al Viro authored
commit c2f18fa4 upstream. * should zero on any failure * __get_user() should use __copy_from_user(), not copy_from_user() Signed-off-by:
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Al Viro authored
commit fd2d2b19 upstream. Signed-off-by:
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Al Viro authored
commit 22426465 upstream. should clear on access_ok() failures. Also remove the useless range truncation logics. Signed-off-by:
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Al Viro authored
commit aace880f upstream. Signed-off-by:
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Al Viro authored
commit acb2505d upstream. ... that should zero on faults. Also remove the <censored> helpful logics wrt range truncation copied from ppc32. Where it had ever been needed only in case of copy_from_user() *and* had not been merged into the mainline until a month after the need had disappeared. A decade before openrisc went into mainline, I might add... Signed-off-by:
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Al Viro authored
commit ae7cc577 upstream. Signed-off-by:
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Al Viro authored
commit 43403eab upstream. Signed-off-by:
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Al Viro authored
commit a5e541f7 upstream. Signed-off-by:
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Al Viro authored
commit f35c1e06 upstream. It's -EFAULT, not -1 (and contrary to the comment in there, __strnlen_user() can return 0 - on faults). Acked-by:
Richard Kuo <rkuo@codeaurora.org> Signed-off-by:
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Al Viro authored
commit 3b8767a8 upstream. It should check access_ok(). Otherwise a bunch of places turn into trivially exploitable rootholes. Signed-off-by:
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Al Viro authored
commit eb47e029 upstream. * copy_from_user() on access_ok() failure ought to zero the destination * none of those primitives should skip the access_ok() check in case of small constant size. Acked-by:
Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by:
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Al Viro authored
commit 9ad18b75 upstream. both for access_ok() failures and for faults halfway through Signed-off-by:
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Herbert Xu authored
commit acdb04d0 upstream. When we need to allocate a temporary blkcipher_walk_next and it fails, the code is supposed to take the slow path of processing the data block by block. However, due to an unrelated change we instead end up dereferencing the NULL pointer. This patch fixes it by moving the unrelated bsize setting out of the way so that we enter the slow path as inteded. Fixes: 7607bd8f ("[CRYPTO] blkcipher: Added blkcipher_walk_virt_block") Reported-by:
xiakaixu <xiakaixu@huawei.com> Reported-by:
Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by:
Herbert Xu <herbert@gondor.apana.org.au> Tested-by:
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Russell King authored
commit 06dfe5cc upstream. SA1111 PCMCIA was broken when PCMCIA switched to using dev_pm_ops for the PCMCIA socket class. PCMCIA used to handle suspend/resume via the socket hosting device, which happened at normal device suspend/resume time. However, the referenced commit changed this: much of the resume now happens much earlier, in the noirq resume handler of dev_pm_ops. However, on SA1111, the PCMCIA device is not accessible as the SA1111 has not been resumed at _noirq time. It's slightly worse than that, because the SA1111 has already been put to sleep at _noirq time, so suspend doesn't work properly. Fix this by converting the core SA1111 code to use dev_pm_ops as well, and performing its own suspend/resume at noirq time. This fixes these errors in the kernel log: pcmcia_socket pcmcia_socket0: time out after reset pcmcia_socket pcmcia_socket1: time out after reset and the resulting lack of PCMCIA cards after a S2RAM cycle. Fixes: d7646f76 ("pcmcia: use dev_pm_ops for class pcmcia_socket_class") Signed-off-by:
Russell King <rmk+kernel@armlinux.org.uk> Signed-off-by:
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Trond Myklebust authored
commit b519d408 upstream. Ensure that we conform to the algorithm described in RFC5661, section 18.36.4 for when to bump the sequence id. In essence we do it for all cases except when the RPC call timed out, or in case of the server returning NFS4ERR_DELAY or NFS4ERR_STALE_CLIENTID. Signed-off-by:
Trond Myklebust <trond.myklebust@primarydata.com> [bwh: Backported to 3.2: - Add the 'out' label - Adjust context] Signed-off-by:
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Karl Beldan authored
commit f6d7c1b5 upstream. This fixes subpage writes when using 4-bit HW ECC. There has been numerous reports about ECC errors with devices using this driver for a while. Also the 4-bit ECC has been reported as broken with subpages in [1] and with 16 bits NANDs in the driver and in mach* board files both in mainline and in the vendor BSPs. What I saw with 4-bit ECC on a 16bits NAND (on an LCDK) which got me to try reinitializing the ECC engine: - R/W on whole pages properly generates/checks RS code - try writing the 1st subpage only of a blank page, the subpage is well written and the RS code properly generated, re-reading the same page the HW detects some ECC error, reading the same page again no ECC error is detected Note that the ECC engine is already reinitialized in the 1-bit case. Tested on my LCDK with UBI+UBIFS using subpages. This could potentially get rid of the issue workarounded in [1]. [1] 28c015a9 ("mtd: davinci-nand: disable subpage write for keystone-nand") Fixes: 6a4123e5 ("mtd: nand: davinci_nand, 4-bit ECC for smallpage") Signed-off-by:
Karl Beldan <kbeldan@baylibre.com> Acked-by:
Boris Brezillon <boris.brezillon@free-electrons.com> Signed-off-by:
Brian Norris <computersforpeace@gmail.com> Signed-off-by:
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Al Viro authored
commit 2545e5da upstream. ... in all cases, including the failing access_ok() Note that some architectures using asm-generic/uaccess.h have __copy_from_user() not zeroing the tail on failure halfway through. This variant works either way. Signed-off-by:
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Al Viro authored
commit 2561d309 upstream. it should clear the destination even when access_ok() fails. Signed-off-by:
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Mathias Krause authored
commit 2f30ea50 upstream. When we fail to attach the security context in xfrm_state_construct() we'll return 0 as error value which, in turn, will wrongly claim success to userland when, in fact, we won't be adding / updating the XFRM state. This is a regression introduced by commit fd21150a ("[XFRM] netlink: Inline attach_encap_tmpl(), attach_sec_ctx(), and attach_one_addr()"). Fix it by propagating the error returned by security_xfrm_state_alloc() in this case. Fixes: fd21150a ("[XFRM] netlink: Inline attach_encap_tmpl()...") Signed-off-by:
Mathias Krause <minipli@googlemail.com> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by:
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Takashi Iwai authored
commit 816f318b upstream. When a seq-virmidi driver is initialized, it registers a rawmidi instance with its callback to create an associated seq kernel client. Currently it's done throughly in rawmidi's register_mutex context. Recently it was found that this may lead to a deadlock another rawmidi device that is being attached with the sequencer is accessed, as both open with the same register_mutex. This was actually triggered by syzkaller, as Dmitry Vyukov reported: ====================================================== [ INFO: possible circular locking dependency detected ] 4.8.0-rc1+ #11 Not tainted ------------------------------------------------------- syz-executor/7154 is trying to acquire lock: (register_mutex#5){+.+.+.}, at: [<ffffffff84fd6d4b>] snd_rawmidi_kernel_open+0x4b/0x260 sound/core/rawmidi.c:341 but task is already holding lock: (&grp->list_mutex){++++.+}, at: [<ffffffff850138bb>] check_and_subscribe_port+0x5b/0x5c0 sound/core/seq/seq_ports.c:495 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&grp->list_mutex){++++.+}: [<ffffffff8147a3a8>] lock_acquire+0x208/0x430 kernel/locking/lockdep.c:3746 [<ffffffff863f6199>] down_read+0x49/0xc0 kernel/locking/rwsem.c:22 [< inline >] deliver_to_subscribers sound/core/seq/seq_clientmgr.c:681 [<ffffffff85005c5e>] snd_seq_deliver_event+0x35e/0x890 sound/core/seq/seq_clientmgr.c:822 [<ffffffff85006e96>] > snd_seq_kernel_client_dispatch+0x126/0x170 sound/core/seq/seq_clientmgr.c:2418 [<ffffffff85012c52>] snd_seq_system_broadcast+0xb2/0xf0 sound/core/seq/seq_system.c:101 [<ffffffff84fff70a>] snd_seq_create_kernel_client+0x24a/0x330 sound/core/seq/seq_clientmgr.c:2297 [< inline >] snd_virmidi_dev_attach_seq sound/core/seq/seq_virmidi.c:383 [<ffffffff8502d29f>] snd_virmidi_dev_register+0x29f/0x750 sound/core/seq/seq_virmidi.c:450 [<ffffffff84fd208c>] snd_rawmidi_dev_register+0x30c/0xd40 sound/core/rawmidi.c:1645 [<ffffffff84f816d3>] __snd_device_register.part.0+0x63/0xc0 sound/core/device.c:164 [< inline >] __snd_device_register sound/core/device.c:162 [<ffffffff84f8235d>] snd_device_register_all+0xad/0x110 sound/core/device.c:212 [<ffffffff84f7546f>] snd_card_register+0xef/0x6c0 sound/core/init.c:749 [<ffffffff85040b7f>] snd_virmidi_probe+0x3ef/0x590 sound/drivers/virmidi.c:123 [<ffffffff833ebf7b>] platform_drv_probe+0x8b/0x170 drivers/base/platform.c:564 ...... -> #0 (register_mutex#5){+.+.+.}: [< inline >] check_prev_add kernel/locking/lockdep.c:1829 [< inline >] check_prevs_add kernel/locking/lockdep.c:1939 [< inline >] validate_chain kernel/locking/lockdep.c:2266 [<ffffffff814791f4>] __lock_acquire+0x4d44/0x4d80 kernel/locking/lockdep.c:3335 [<ffffffff8147a3a8>] lock_acquire+0x208/0x430 kernel/locking/lockdep.c:3746 [< inline >] __mutex_lock_common kernel/locking/mutex.c:521 [<ffffffff863f0ef1>] mutex_lock_nested+0xb1/0xa20 kernel/locking/mutex.c:621 [<ffffffff84fd6d4b>] snd_rawmidi_kernel_open+0x4b/0x260 sound/core/rawmidi.c:341 [<ffffffff8502e7c7>] midisynth_subscribe+0xf7/0x350 sound/core/seq/seq_midi.c:188 [< inline >] subscribe_port sound/core/seq/seq_ports.c:427 [<ffffffff85013cc7>] check_and_subscribe_port+0x467/0x5c0 sound/core/seq/seq_ports.c:510 [<ffffffff85015da9>] snd_seq_port_connect+0x2c9/0x500 sound/core/seq/seq_ports.c:579 [<ffffffff850079b8>] snd_seq_ioctl_subscribe_port+0x1d8/0x2b0 sound/core/seq/seq_clientmgr.c:1480 [<ffffffff84ffe9e4>] snd_seq_do_ioctl+0x184/0x1e0 sound/core/seq/seq_clientmgr.c:2225 [<ffffffff84ffeae8>] snd_seq_kernel_client_ctl+0xa8/0x110 sound/core/seq/seq_clientmgr.c:2440 [<ffffffff85027664>] snd_seq_oss_midi_open+0x3b4/0x610 sound/core/seq/oss/seq_oss_midi.c:375 [<ffffffff85023d67>] snd_seq_oss_synth_setup_midi+0x107/0x4c0 sound/core/seq/oss/seq_oss_synth.c:281 [<ffffffff8501b0a8>] snd_seq_oss_open+0x748/0x8d0 sound/core/seq/oss/seq_oss_init.c:274 [<ffffffff85019d8a>] odev_open+0x6a/0x90 sound/core/seq/oss/seq_oss.c:138 [<ffffffff84f7040f>] soundcore_open+0x30f/0x640 sound/sound_core.c:639 ...... other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&grp->list_mutex); lock(register_mutex#5); lock(&grp->list_mutex); lock(register_mutex#5); *** DEADLOCK *** ====================================================== The fix is to simply move the registration parts in snd_rawmidi_dev_register() to the outside of the register_mutex lock. The lock is needed only to manage the linked list, and it's not necessarily to cover the whole initialization process. Reported-by:
Dmitry Vyukov <dvyukov@google.com> Signed-off-by:
Takashi Iwai <tiwai@suse.de> [bwh: Backported to 3.2: adjust context] Signed-off-by:
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Takashi Iwai authored
commit 9f8a7658 upstream. When a user timer instance is continued without the explicit start beforehand, the system gets eventually zero-division error like: divide error: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN CPU: 1 PID: 27320 Comm: syz-executor Not tainted 4.8.0-rc3-next-20160825+ #8 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88003c9b2280 task.stack: ffff880027280000 RIP: 0010:[<ffffffff858e1a6c>] [< inline >] ktime_divns include/linux/ktime.h:195 RIP: 0010:[<ffffffff858e1a6c>] [<ffffffff858e1a6c>] snd_hrtimer_callback+0x1bc/0x3c0 sound/core/hrtimer.c:62 Call Trace: <IRQ> [< inline >] __run_hrtimer kernel/time/hrtimer.c:1238 [<ffffffff81504335>] __hrtimer_run_queues+0x325/0xe70 kernel/time/hrtimer.c:1302 [<ffffffff81506ceb>] hrtimer_interrupt+0x18b/0x420 kernel/time/hrtimer.c:1336 [<ffffffff8126d8df>] local_apic_timer_interrupt+0x6f/0xe0 arch/x86/kernel/apic/apic.c:933 [<ffffffff86e13056>] smp_apic_timer_interrupt+0x76/0xa0 arch/x86/kernel/apic/apic.c:957 [<ffffffff86e1210c>] apic_timer_interrupt+0x8c/0xa0 arch/x86/entry/entry_64.S:487 <EOI> ..... Although a similar issue was spotted and a fix patch was merged in commit [6b760bb2: ALSA: timer: fix division by zero after SNDRV_TIMER_IOCTL_CONTINUE], it seems covering only a part of iceberg. In this patch, we fix the issue a bit more drastically. Basically the continue of an uninitialized timer is supposed to be a fresh start, so we do it for user timers. For the direct snd_timer_continue() call, there is no way to pass the initial tick value, so we kick out for the uninitialized case. Reported-by:
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Takashi Iwai authored
commit c3b16813 upstream. This is a minor code cleanup without any functional changes: - Kill keep_flag argument from _snd_timer_stop(), as all callers pass only it false. - Remove redundant NULL check in _snd_timer_stop(). Signed-off-by:
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Ard Biesheuvel authored
commit 0bd22235 upstream. When calling .import() on a cryptd ahash_request, the structure members that describe the child transform in the shash_desc need to be initialized like they are when calling .init() Signed-off-by:
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Balbir Singh authored
commit 135e8c92 upstream. The origin of the issue I've seen is related to a missing memory barrier between check for task->state and the check for task->on_rq. The task being woken up is already awake from a schedule() and is doing the following: do { schedule() set_current_state(TASK_(UN)INTERRUPTIBLE); } while (!cond); The waker, actually gets stuck doing the following in try_to_wake_up(): while (p->on_cpu) cpu_relax(); Analysis: The instance I've seen involves the following race: CPU1 CPU2 while () { if (cond) break; do { schedule(); set_current_state(TASK_UN..) } while (!cond); wakeup_routine() spin_lock_irqsave(wait_lock) raw_spin_lock_irqsave(wait_lock) wake_up_process() } try_to_wake_up() set_current_state(TASK_RUNNING); .. list_del(&waiter.list); CPU2 wakes up CPU1, but before it can get the wait_lock and set current state to TASK_RUNNING the following occurs: CPU3 wakeup_routine() raw_spin_lock_irqsave(wait_lock) if (!list_empty) wake_up_process() try_to_wake_up() raw_spin_lock_irqsave(p->pi_lock) .. if (p->on_rq && ttwu_wakeup()) .. while (p->on_cpu) cpu_relax() .. CPU3 tries to wake up the task on CPU1 again since it finds it on the wait_queue, CPU1 is spinning on wait_lock, but immediately after CPU2, CPU3 got it. CPU3 checks the state of p on CPU1, it is TASK_UNINTERRUPTIBLE and the task is spinning on the wait_lock. Interestingly since p->on_rq is checked under pi_lock, I've noticed that try_to_wake_up() finds p->on_rq to be 0. This was the most confusing bit of the analysis, but p->on_rq is changed under runqueue lock, rq_lock, the p->on_rq check is not reliable without this fix IMHO. The race is visible (based on the analysis) only when ttwu_queue() does a remote wakeup via ttwu_queue_remote. In which case the p->on_rq change is not done uder the pi_lock. The result is that after a while the entire system locks up on the raw_spin_irqlock_save(wait_lock) and the holder spins infintely Reproduction of the issue: The issue can be reproduced after a long run on my system with 80 threads and having to tweak available memory to very low and running memory stress-ng mmapfork test. It usually takes a long time to reproduce. I am trying to work on a test case that can reproduce the issue faster, but thats work in progress. I am still testing the changes on my still in a loop and the tests seem OK thus far. Big thanks to Benjamin and Nick for helping debug this as well. Ben helped catch the missing barrier, Nick caught every missing bit in my theory. Signed-off-by:
Balbir Singh <bsingharora@gmail.com> [ Updated comment to clarify matching barriers. Many architectures do not have a full barrier in switch_to() so that cannot be relied upon. ] Signed-off-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Alexey Kardashevskiy <aik@ozlabs.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nicholas Piggin <nicholas.piggin@gmail.com> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/e02cce7b-d9ca-1ad0-7a61-ea97c7582b37@gmail.comSigned-off-by:
Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.2: adjust filename] Signed-off-by:
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