kernel/linux.git/include, branch v3.0.32

usbnet: fix skb traversing races during unlink(v2)

2012-05-21T16:40:01+00:00

commit 5b6e9bcdeb65634b4ad604eb4536404bbfc62cfa upstream. Commit 4231d47e6fe69f061f96c98c30eaf9fb4c14b96d(net/usbnet: avoid recursive locking in usbnet_stop()) fixes the recursive locking problem by releasing the skb queue lock before unlink, but may cause skb traversing races: - after URB is unlinked and the queue lock is released, the refered skb and skb->next may be moved to done queue, even be released - in skb_queue_walk_safe, the next skb is still obtained by next pointer of the last skb - so maybe trigger oops or other problems This patch extends the usage of entry->state to describe 'start_unlink' state, so always holding the queue(rx/tx) lock to change the state if the referd skb is in rx or tx queue because we need to know if the refered urb has been started unlinking in unlink_urbs. The other part of this patch is based on Huajun's patch: always traverse from head of the tx/rx queue to get skb which is to be unlinked but not been started unlinking. Signed-off-by: Huajun Li Signed-off-by: Ming Lei Cc: Oliver Neukum Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Fix __read_seqcount_begin() to use ACCESS_ONCE for sequence value read

2012-05-21T16:39:58+00:00

commit 2f624278626677bfaf73fef97f86b37981621f5c upstream. We really need to use a ACCESS_ONCE() on the sequence value read in __read_seqcount_begin(), because otherwise the compiler might end up reloading the value in between the test and the return of it. As a result, it might end up returning an odd value (which means that a write is in progress). If the reader is then fast enough that that odd value is still the current one when the read_seqcount_retry() is done, we might end up with a "successful" read sequence, even despite the concurrent write being active. In practice this probably never really happens - there just isn't anything else going on around the read of the sequence count, and the common case is that we end up having a read barrier immediately afterwards. So the code sequence in which gcc might decide to reaload from memory is small, and there's no reason to believe it would ever actually do the reload. But if the compiler ever were to decide to do so, it would be incredibly annoying to debug. Let's just make sure. Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

asm-generic: Use __BITS_PER_LONG in statfs.h

2012-05-21T16:39:58+00:00

commit f5c2347ee20a8d6964d6a6b1ad04f200f8d4dfa7 upstream. is exported to userspace, so using BITS_PER_LONG is invalid. We need to use __BITS_PER_LONG instead. This is kernel bugzilla 43165. Reported-by: H.J. Lu Signed-off-by: H. Peter Anvin Link: http://lkml.kernel.org/r/1335465916-16965-1-git-send-email-hpa@linux.intel.com Acked-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

efi: Add new variable attributes

2012-05-07T15:56:37+00:00

commit 41b3254c93acc56adc3c4477fef7c9512d47659e upstream. More recent versions of the UEFI spec have added new attributes for variables. Add them. Signed-off-by: Matthew Garrett Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

pipes: add a "packetized pipe" mode for writing

2012-05-07T15:56:36+00:00

commit 9883035ae7edef3ec62ad215611cb8e17d6a1a5d upstream. The actual internal pipe implementation is already really about individual packets (called "pipe buffers"), and this simply exposes that as a special packetized mode. When we are in the packetized mode (marked by O_DIRECT as suggested by Alan Cox), a write() on a pipe will not merge the new data with previous writes, so each write will get a pipe buffer of its own. The pipe buffer is then marked with the PIPE_BUF_FLAG_PACKET flag, which in turn will tell the reader side to break the read at that boundary (and throw away any partial packet contents that do not fit in the read buffer). End result: as long as you do writes less than PIPE_BUF in size (so that the pipe doesn't have to split them up), you can now treat the pipe as a packet interface, where each read() system call will read one packet at a time. You can just use a sufficiently big read buffer (PIPE_BUF is sufficient, since bigger than that doesn't guarantee atomicity anyway), and the return value of the read() will naturally give you the size of the packet. NOTE! We do not support zero-sized packets, and zero-sized reads and writes to a pipe continue to be no-ops. Also note that big packets will currently be split at write time, but that the size at which that happens is not really specified (except that it's bigger than PIPE_BUF). Currently that limit is the system page size, but we might want to explicitly support bigger packets some day. The main user for this is going to be the autofs packet interface, allowing us to stop having to care so deeply about exact packet sizes (which have had bugs with 32/64-bit compatibility modes). But user space can create packetized pipes with "pipe2(fd, O_DIRECT)", which will fail with an EINVAL on kernels that do not support this interface. Tested-by: Michael Tokarev Cc: Alan Cox Cc: David Miller Cc: Ian Kent Cc: Thomas Meyer Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

USB: EHCI: fix crash during suspend on ASUS computers

2012-05-07T15:56:36+00:00

commit 151b61284776be2d6f02d48c23c3625678960b97 upstream. This patch (as1545) fixes a problem affecting several ASUS computers: The machine crashes or corrupts memory when going into suspend if the ehci-hcd driver is bound to any controllers. Users have been forced to unbind or unload ehci-hcd before putting their systems to sleep. After extensive testing, it was determined that the machines don't like going into suspend when any EHCI controllers are in the PCI D3 power state. Presumably this is a firmware bug, but there's nothing we can do about it except to avoid putting the controllers in D3 during system sleep. The patch adds a new flag to indicate whether the problem is present, and avoids changing the controller's power state if the flag is set. Runtime suspend is unaffected; this matters only for system suspend. However as a side effect, the controller will not respond to remote wakeup requests while the system is asleep. Hence USB wakeup is not functional -- but of course, this is already true in the current state of affairs. This fixes Bugzilla #42728. Signed-off-by: Alan Stern Tested-by: Steven Rostedt Tested-by: Andrey Rahmatullin Tested-by: Oleksij Rempel (fishor) Signed-off-by: Greg Kroah-Hartman

KVM: unmap pages from the iommu when slots are removed

2012-05-07T15:56:35+00:00

commit 32f6daad4651a748a58a3ab6da0611862175722f upstream. We've been adding new mappings, but not destroying old mappings. This can lead to a page leak as pages are pinned using get_user_pages, but only unpinned with put_page if they still exist in the memslots list on vm shutdown. A memslot that is destroyed while an iommu domain is enabled for the guest will therefore result in an elevated page reference count that is never cleared. Additionally, without this fix, the iommu is only programmed with the first translation for a gpa. This can result in peer-to-peer errors if a mapping is destroyed and replaced by a new mapping at the same gpa as the iommu will still be pointing to the original, pinned memory address. Signed-off-by: Alex Williamson Signed-off-by: Marcelo Tosatti Signed-off-by: Jonathan Nieder Signed-off-by: Greg Kroah-Hartman

tcp: allow splice() to build full TSO packets

2012-04-27T16:51:18+00:00

[ This combines upstream commit 2f53384424251c06038ae612e56231b96ab610ee and the follow-on bug fix commit 35f9c09fe9c72eb8ca2b8e89a593e1c151f28fc2 ] vmsplice()/splice(pipe, socket) call do_tcp_sendpages() one page at a time, adding at most 4096 bytes to an skb. (assuming PAGE_SIZE=4096) The call to tcp_push() at the end of do_tcp_sendpages() forces an immediate xmit when pipe is not already filled, and tso_fragment() try to split these skb to MSS multiples. 4096 bytes are usually split in a skb with 2 MSS, and a remaining sub-mss skb (assuming MTU=1500) This makes slow start suboptimal because many small frames are sent to qdisc/driver layers instead of big ones (constrained by cwnd and packets in flight of course) In fact, applications using sendmsg() (adding an additional memory copy) instead of vmsplice()/splice()/sendfile() are a bit faster because of this anomaly, especially if serving small files in environments with large initial [c]wnd. Call tcp_push() only if MSG_MORE is not set in the flags parameter. This bit is automatically provided by splice() internals but for the last page, or on all pages if user specified SPLICE_F_MORE splice() flag. In some workloads, this can reduce number of sent logical packets by an order of magnitude, making zero-copy TCP actually faster than one-copy :) Reported-by: Tom Herbert Cc: Nandita Dukkipati Cc: Neal Cardwell Cc: Tom Herbert Cc: Yuchung Cheng Cc: H.K. Jerry Chu Cc: Maciej Żenczykowski Cc: Mahesh Bandewar Cc: Ilpo Järvinen Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

Bluetooth: hci_core: fix NULL-pointer dereference at unregister

2012-04-22T23:21:42+00:00

commit 94324962066231a938564bebad0f941cd2d06bb2 upstream. Make sure hci_dev_open returns immediately if hci_dev_unregister has been called. This fixes a race between hci_dev_open and hci_dev_unregister which can lead to a NULL-pointer dereference. Bug is 100% reproducible using hciattach and a disconnected serial port: 0. # hciattach -n /dev/ttyO1 any noflow 1. hci_dev_open called from hci_power_on grabs req lock 2. hci_init_req executes but device fails to initialise (times out eventually) 3. hci_dev_open is called from hci_sock_ioctl and sleeps on req lock 4. hci_uart_tty_close calls hci_dev_unregister and sleeps on req lock in hci_dev_do_close 5. hci_dev_open (1) releases req lock 6. hci_dev_do_close grabs req lock and returns as device is not up 7. hci_dev_unregister sleeps in destroy_workqueue 8. hci_dev_open (3) grabs req lock, calls hci_init_req and eventually sleeps 9. hci_dev_unregister finishes, while hci_dev_open is still running... [ 79.627136] INFO: trying to register non-static key. [ 79.632354] the code is fine but needs lockdep annotation. [ 79.638122] turning off the locking correctness validator. [ 79.643920] [] (unwind_backtrace+0x0/0xf8) from [] (__lock_acquire+0x1590/0x1ab0) [ 79.653594] [] (__lock_acquire+0x1590/0x1ab0) from [] (lock_acquire+0x9c/0x128) [ 79.663085] [] (lock_acquire+0x9c/0x128) from [] (run_timer_softirq+0x150/0x3ac) [ 79.672668] [] (run_timer_softirq+0x150/0x3ac) from [] (__do_softirq+0xd4/0x22c) [ 79.682281] [] (__do_softirq+0xd4/0x22c) from [] (irq_exit+0x8c/0x94) [ 79.690856] [] (irq_exit+0x8c/0x94) from [] (handle_IRQ+0x34/0x84) [ 79.699157] [] (handle_IRQ+0x34/0x84) from [] (omap3_intc_handle_irq+0x48/0x4c) [ 79.708648] [] (omap3_intc_handle_irq+0x48/0x4c) from [] (__irq_usr+0x3c/0x60) [ 79.718048] Exception stack(0xcf281fb0 to 0xcf281ff8) [ 79.723358] 1fa0: 0001e6a0 be8dab00 0001e698 00036698 [ 79.731933] 1fc0: 0002df98 0002df38 0000001f 00000000 b6f234d0 00000000 00000004 00000000 [ 79.740509] 1fe0: 0001e6f8 be8d6aa0 be8dac50 0000aab8 80000010 ffffffff [ 79.747497] Unable to handle kernel NULL pointer dereference at virtual address 00000000 [ 79.756011] pgd = cf3b4000 [ 79.758850] [00000000] *pgd=8f0c7831, *pte=00000000, *ppte=00000000 [ 79.765502] Internal error: Oops: 80000007 [#1] [ 79.770294] Modules linked in: [ 79.773529] CPU: 0 Tainted: G W (3.3.0-rc6-00002-gb5d5c87 #421) [ 79.781066] PC is at 0x0 [ 79.783721] LR is at run_timer_softirq+0x16c/0x3ac [ 79.788787] pc : [<00000000>] lr : [] psr: 60000113 [ 79.788787] sp : cf281ee0 ip : 00000000 fp : cf280000 [ 79.800903] r10: 00000004 r9 : 00000100 r8 : b6f234d0 [ 79.806427] r7 : c0519c28 r6 : cf093488 r5 : c0561a00 r4 : 00000000 [ 79.813323] r3 : 00000000 r2 : c054eee0 r1 : 00000001 r0 : 00000000 [ 79.820190] Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user [ 79.827728] Control: 10c5387d Table: 8f3b4019 DAC: 00000015 [ 79.833801] Process gpsd (pid: 1265, stack limit = 0xcf2802e8) [ 79.839965] Stack: (0xcf281ee0 to 0xcf282000) [ 79.844573] 1ee0: 00000002 00000000 c0040a24 00000000 00000002 cf281f08 00200200 00000000 [ 79.853210] 1f00: 00000000 cf281f18 cf281f08 00000000 00000000 00000000 cf281f18 cf281f18 [ 79.861816] 1f20: 00000000 00000001 c056184c 00000000 00000001 b6f234d0 c0561848 00000004 [ 79.870452] 1f40: cf280000 c003a3b8 c051e79c 00000001 00000000 00000100 3fa9e7b8 0000000a [ 79.879089] 1f60: 00000025 cf280000 00000025 00000000 00000000 b6f234d0 00000000 00000004 [ 79.887756] 1f80: 00000000 c003a924 c053ad38 c0013a50 fa200000 cf281fb0 ffffffff c0008530 [ 79.896362] 1fa0: 0001e6a0 0000aab8 80000010 c037499c 0001e6a0 be8dab00 0001e698 00036698 [ 79.904998] 1fc0: 0002df98 0002df38 0000001f 00000000 b6f234d0 00000000 00000004 00000000 [ 79.913665] 1fe0: 0001e6f8 be8d6aa0 be8dac50 0000aab8 80000010 ffffffff 00fbf700 04ffff00 [ 79.922302] [] (run_timer_softirq+0x16c/0x3ac) from [] (__do_softirq+0xd4/0x22c) [ 79.931945] [] (__do_softirq+0xd4/0x22c) from [] (irq_exit+0x8c/0x94) [ 79.940582] [] (irq_exit+0x8c/0x94) from [] (handle_IRQ+0x34/0x84) [ 79.948913] [] (handle_IRQ+0x34/0x84) from [] (omap3_intc_handle_irq+0x48/0x4c) [ 79.958404] [] (omap3_intc_handle_irq+0x48/0x4c) from [] (__irq_usr+0x3c/0x60) [ 79.967773] Exception stack(0xcf281fb0 to 0xcf281ff8) [ 79.973083] 1fa0: 0001e6a0 be8dab00 0001e698 00036698 [ 79.981658] 1fc0: 0002df98 0002df38 0000001f 00000000 b6f234d0 00000000 00000004 00000000 [ 79.990234] 1fe0: 0001e6f8 be8d6aa0 be8dac50 0000aab8 80000010 ffffffff [ 79.997161] Code: bad PC value [ 80.000396] ---[ end trace 6f6739840475f9ee ]--- [ 80.005279] Kernel panic - not syncing: Fatal exception in interrupt Signed-off-by: Johan Hovold Acked-by: Marcel Holtmann Signed-off-by: Johan Hedberg Signed-off-by: Greg Kroah-Hartman

sched/x86: Fix overflow in cyc2ns_offset

2012-04-13T15:14:08+00:00

commit 9993bc635d01a6ee7f6b833b4ee65ce7c06350b1 upstream. When a machine boots up, the TSC generally gets reset. However, when kexec is used to boot into a kernel, the TSC value would be carried over from the previous kernel. The computation of cycns_offset in set_cyc2ns_scale is prone to an overflow, if the machine has been up more than 208 days prior to the kexec. The overflow happens when we multiply *scale, even though there is enough room to store the final answer. We fix this issue by decomposing tsc_now into the quotient and remainder of division by CYC2NS_SCALE_FACTOR and then performing the multiplication separately on the two components. Refactor code to share the calculation with the previous fix in __cycles_2_ns(). Signed-off-by: Salman Qazi Acked-by: John Stultz Acked-by: Peter Zijlstra Cc: Paul Turner Cc: john stultz Link: http://lkml.kernel.org/r/20120310004027.19291.88460.stgit@dungbeetle.mtv.corp.google.com Signed-off-by: Ingo Molnar Cc: Mike Galbraith Signed-off-by: Greg Kroah-Hartman