kernel/linux.git/include, branch v3.4.6

NFC: Export nfc.h to userland

2012-07-19T15:59:00+00:00

commit dbd4fcaf8d664fab4163b1f8682e41ad8bff3444 upstream. The netlink commands and attributes, along with the socket structure definitions need to be exported. Signed-off-by: Samuel Ortiz Signed-off-by: John W. Linville Signed-off-by: Greg Kroah-Hartman

timekeeping: Provide hrtimer update function

2012-07-19T15:59:00+00:00

This is a backport of f6c06abfb3972ad4914cef57d8348fcb2932bc3b To finally fix the infamous leap second issue and other race windows caused by functions which change the offsets between the various time bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a function which atomically gets the current monotonic time and updates the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic overhead. The previous patch which provides ktime_t offsets allows us to make this function almost as cheap as ktime_get() which is going to be replaced in hrtimer_interrupt(). Signed-off-by: Thomas Gleixner Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Prarit Bhargava Signed-off-by: John Stultz Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz Signed-off-by: Greg Kroah-Hartman

hrtimer: Provide clock_was_set_delayed()

2012-07-19T15:58:59+00:00

This is a backport of f55a6faa384304c89cfef162768e88374d3312cb clock_was_set() cannot be called from hard interrupt context because it calls on_each_cpu(). For fixing the widely reported leap seconds issue it is necessary to call it from hard interrupt context, i.e. the timer tick code, which does the timekeeping updates. Provide a new function which denotes it in the hrtimer cpu base structure of the cpu on which it is called and raise the hrtimer softirq. We then execute the clock_was_set() notificiation from softirq context in run_hrtimer_softirq(). The hrtimer softirq is rarely used, so polling the flag there is not a performance issue. [ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get rid of all this ifdeffery ASAP ] Signed-off-by: John Stultz Reported-by: Jan Engelhardt Reviewed-by: Ingo Molnar Acked-by: Peter Zijlstra Acked-by: Prarit Bhargava Link: http://lkml.kernel.org/r/1341960205-56738-2-git-send-email-johnstul@us.ibm.com Signed-off-by: Thomas Gleixner Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz Signed-off-by: Greg Kroah-Hartman

sched/nohz: Rewrite and fix load-avg computation -- again

2012-07-19T15:58:56+00:00

commit 5167e8d5417bf5c322a703d2927daec727ea40dd upstream. Thanks to Charles Wang for spotting the defects in the current code: - If we go idle during the sample window -- after sampling, we get a negative bias because we can negate our own sample. - If we wake up during the sample window we get a positive bias because we push the sample to a known active period. So rewrite the entire nohz load-avg muck once again, now adding copious documentation to the code. Reported-and-tested-by: Doug Smythies Reported-and-tested-by: Charles Wang Signed-off-by: Peter Zijlstra Cc: Linus Torvalds Cc: Andrew Morton Link: http://lkml.kernel.org/r/1340373782.18025.74.camel@twins [ minor edits ] Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman

memblock: free allocated memblock_reserved_regions later

2012-07-16T16:04:45+00:00

commit 29f6738609e40227dabcc63bfb3b84b3726a75bd upstream. memblock_free_reserved_regions() calls memblock_free(), but memblock_free() would double reserved.regions too, so we could free the old range for reserved.regions. Also tj said there is another bug which could be related to this. | I don't think we're saving any noticeable | amount by doing this "free - give it to page allocator - reserve | again" dancing. We should just allocate regions aligned to page | boundaries and free them later when memblock is no longer in use. in that case, when DEBUG_PAGEALLOC, will get panic: memblock_free: [0x0000102febc080-0x0000102febf080] memblock_free_reserved_regions+0x37/0x39 BUG: unable to handle kernel paging request at ffff88102febd948 IP: [] __next_free_mem_range+0x9b/0x155 PGD 4826063 PUD cf67a067 PMD cf7fa067 PTE 800000102febd160 Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC CPU 0 Pid: 0, comm: swapper Not tainted 3.5.0-rc2-next-20120614-sasha #447 RIP: 0010:[] [] __next_free_mem_range+0x9b/0x155 See the discussion at https://lkml.org/lkml/2012/6/13/469 So try to allocate with PAGE_SIZE alignment and free it later. Reported-by: Sasha Levin Acked-by: Tejun Heo Cc: Benjamin Herrenschmidt Signed-off-by: Yinghai Lu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

memory hotplug: fix invalid memory access caused by stale kswapd pointer

2012-07-16T16:04:44+00:00

commit d8adde17e5f858427504725218c56aef90e90fc7 upstream. kswapd_stop() is called to destroy the kswapd work thread when all memory of a NUMA node has been offlined. But kswapd_stop() only terminates the work thread without resetting NODE_DATA(nid)->kswapd to NULL. The stale pointer will prevent kswapd_run() from creating a new work thread when adding memory to the memory-less NUMA node again. Eventually the stale pointer may cause invalid memory access. An example stack dump as below. It's reproduced with 2.6.32, but latest kernel has the same issue. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [] exit_creds+0x12/0x78 PGD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/memory/memory391/state CPU 11 Modules linked in: cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq microcode fuse loop dm_mod tpm_tis rtc_cmos i2c_i801 rtc_core tpm serio_raw pcspkr sg tpm_bios igb i2c_core iTCO_wdt rtc_lib mptctl iTCO_vendor_support button dca bnx2 usbhid hid uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif edd ext3 mbcache jbd fan ide_pci_generic ide_core ata_generic ata_piix libata thermal processor thermal_sys hwmon mptsas mptscsih mptbase scsi_transport_sas scsi_mod Pid: 7949, comm: sh Not tainted 2.6.32.12-qiuxishi-5-default #92 Tecal RH2285 RIP: 0010:exit_creds+0x12/0x78 RSP: 0018:ffff8806044f1d78 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff880604f22140 RCX: 0000000000019502 RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000 RBP: ffff880604f22150 R08: 0000000000000000 R09: ffffffff81a4dc10 R10: 00000000000032a0 R11: ffff880006202500 R12: 0000000000000000 R13: 0000000000c40000 R14: 0000000000008000 R15: 0000000000000001 FS: 00007fbc03d066f0(0000) GS:ffff8800282e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 000000060f029000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 7949, threadinfo ffff8806044f0000, task ffff880603d7c600) Stack: ffff880604f22140 ffffffff8103aac5 ffff880604f22140 ffffffff8104d21e ffff880006202500 0000000000008000 0000000000c38000 ffffffff810bd5b1 0000000000000000 ffff880603d7c600 00000000ffffdd29 0000000000000003 Call Trace: __put_task_struct+0x5d/0x97 kthread_stop+0x50/0x58 offline_pages+0x324/0x3da memory_block_change_state+0x179/0x1db store_mem_state+0x9e/0xbb sysfs_write_file+0xd0/0x107 vfs_write+0xad/0x169 sys_write+0x45/0x6e system_call_fastpath+0x16/0x1b Code: ff 4d 00 0f 94 c0 84 c0 74 08 48 89 ef e8 1f fd ff ff 5b 5d 31 c0 41 5c c3 53 48 8b 87 20 06 00 00 48 89 fb 48 8b bf 18 06 00 00 <8b> 00 48 c7 83 18 06 00 00 00 00 00 00 f0 ff 0f 0f 94 c0 84 c0 RIP exit_creds+0x12/0x78 RSP CR2: 0000000000000000 [akpm@linux-foundation.org: add pglist_data.kswapd locking comments] Signed-off-by: Xishi Qiu Signed-off-by: Jiang Liu Acked-by: KAMEZAWA Hiroyuki Acked-by: KOSAKI Motohiro Acked-by: Mel Gorman Acked-by: David Rientjes Reviewed-by: Minchan Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

splice: fix racy pipe->buffers uses

2012-07-16T16:04:42+00:00

commit 047fe3605235888f3ebcda0c728cb31937eadfe6 upstream. Dave Jones reported a kernel BUG at mm/slub.c:3474! triggered by splice_shrink_spd() called from vmsplice_to_pipe() commit 35f3d14dbbc5 (pipe: add support for shrinking and growing pipes) added capability to adjust pipe->buffers. Problem is some paths don't hold pipe mutex and assume pipe->buffers doesn't change for their duration. Fix this by adding nr_pages_max field in struct splice_pipe_desc, and use it in place of pipe->buffers where appropriate. splice_shrink_spd() loses its struct pipe_inode_info argument. Reported-by: Dave Jones Signed-off-by: Eric Dumazet Cc: Jens Axboe Cc: Alexander Viro Cc: Tom Herbert Tested-by: Dave Jones Signed-off-by: Jens Axboe [bwh: Backported to 3.2: - Adjust context in vmsplice_to_pipe() - Update one more call to splice_shrink_spd(), from skb_splice_bits()] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

thp: avoid atomic64_read in pmd_read_atomic for 32bit PAE

2012-07-16T16:04:42+00:00

commit e4eed03fd06578571c01d4f1478c874bb432c815 upstream. In the x86 32bit PAE CONFIG_TRANSPARENT_HUGEPAGE=y case while holding the mmap_sem for reading, cmpxchg8b cannot be used to read pmd contents under Xen. So instead of dealing only with "consistent" pmdvals in pmd_none_or_trans_huge_or_clear_bad() (which would be conceptually simpler) we let pmd_none_or_trans_huge_or_clear_bad() deal with pmdvals where the low 32bit and high 32bit could be inconsistent (to avoid having to use cmpxchg8b). The only guarantee we get from pmd_read_atomic is that if the low part of the pmd was found null, the high part will be null too (so the pmd will be considered unstable). And if the low part of the pmd is found "stable" later, then it means the whole pmd was read atomically (because after a pmd is stable, neither MADV_DONTNEED nor page faults can alter it anymore, and we read the high part after the low part). In the 32bit PAE x86 case, it is enough to read the low part of the pmdval atomically to declare the pmd as "stable" and that's true for THP and no THP, furthermore in the THP case we also have a barrier() that will prevent any inconsistent pmdvals to be cached by a later re-read of the *pmd. Signed-off-by: Andrea Arcangeli Cc: Jonathan Nieder Cc: Ulrich Obergfell Cc: Mel Gorman Cc: Hugh Dickins Cc: Larry Woodman Cc: Petr Matousek Cc: Rik van Riel Cc: Jan Beulich Cc: KOSAKI Motohiro Tested-by: Andrew Jones Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

mm: pmd_read_atomic: fix 32bit PAE pmd walk vs pmd_populate SMP race condition

2012-07-16T16:04:41+00:00

commit 26c191788f18129af0eb32a358cdaea0c7479626 upstream. When holding the mmap_sem for reading, pmd_offset_map_lock should only run on a pmd_t that has been read atomically from the pmdp pointer, otherwise we may read only half of it leading to this crash. PID: 11679 TASK: f06e8000 CPU: 3 COMMAND: "do_race_2_panic" #0 [f06a9dd8] crash_kexec at c049b5ec #1 [f06a9e2c] oops_end at c083d1c2 #2 [f06a9e40] no_context at c0433ded #3 [f06a9e64] bad_area_nosemaphore at c043401a #4 [f06a9e6c] __do_page_fault at c0434493 #5 [f06a9eec] do_page_fault at c083eb45 #6 [f06a9f04] error_code (via page_fault) at c083c5d5 EAX: 01fb470c EBX: fff35000 ECX: 00000003 EDX: 00000100 EBP: 00000000 DS: 007b ESI: 9e201000 ES: 007b EDI: 01fb4700 GS: 00e0 CS: 0060 EIP: c083bc14 ERR: ffffffff EFLAGS: 00010246 #7 [f06a9f38] _spin_lock at c083bc14 #8 [f06a9f44] sys_mincore at c0507b7d #9 [f06a9fb0] system_call at c083becd start len EAX: ffffffda EBX: 9e200000 ECX: 00001000 EDX: 6228537f DS: 007b ESI: 00000000 ES: 007b EDI: 003d0f00 SS: 007b ESP: 62285354 EBP: 62285388 GS: 0033 CS: 0073 EIP: 00291416 ERR: 000000da EFLAGS: 00000286 This should be a longstanding bug affecting x86 32bit PAE without THP. Only archs with 64bit large pmd_t and 32bit unsigned long should be affected. With THP enabled the barrier() in pmd_none_or_trans_huge_or_clear_bad() would partly hide the bug when the pmd transition from none to stable, by forcing a re-read of the *pmd in pmd_offset_map_lock, but when THP is enabled a new set of problem arises by the fact could then transition freely in any of the none, pmd_trans_huge or pmd_trans_stable states. So making the barrier in pmd_none_or_trans_huge_or_clear_bad() unconditional isn't good idea and it would be a flakey solution. This should be fully fixed by introducing a pmd_read_atomic that reads the pmd in order with THP disabled, or by reading the pmd atomically with cmpxchg8b with THP enabled. Luckily this new race condition only triggers in the places that must already be covered by pmd_none_or_trans_huge_or_clear_bad() so the fix is localized there but this bug is not related to THP. NOTE: this can trigger on x86 32bit systems with PAE enabled with more than 4G of ram, otherwise the high part of the pmd will never risk to be truncated because it would be zero at all times, in turn so hiding the SMP race. This bug was discovered and fully debugged by Ulrich, quote: ---- [..] pmd_none_or_trans_huge_or_clear_bad() loads the content of edx and eax. 496 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd) 497 { 498 /* depend on compiler for an atomic pmd read */ 499 pmd_t pmdval = *pmd; // edi = pmd pointer 0xc0507a74 : mov 0x8(%esp),%edi ... // edx = PTE page table high address 0xc0507a84 : mov 0x4(%edi),%edx ... // eax = PTE page table low address 0xc0507a8e : mov (%edi),%eax [..] Please note that the PMD is not read atomically. These are two "mov" instructions where the high order bits of the PMD entry are fetched first. Hence, the above machine code is prone to the following race. - The PMD entry {high|low} is 0x0000000000000000. The "mov" at 0xc0507a84 loads 0x00000000 into edx. - A page fault (on another CPU) sneaks in between the two "mov" instructions and instantiates the PMD. - The PMD entry {high|low} is now 0x00000003fda38067. The "mov" at 0xc0507a8e loads 0xfda38067 into eax. ---- Reported-by: Ulrich Obergfell Signed-off-by: Andrea Arcangeli Cc: Mel Gorman Cc: Hugh Dickins Cc: Larry Woodman Cc: Petr Matousek Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

SUNRPC: new svc_bind() routine introduced

2012-07-16T16:04:39+00:00

upstream commit 9793f7c88937e7ac07305ab1af1a519225836823. This new routine is responsible for service registration in a specified network context. The idea is to separate service creation from per-net operations. Note also: since registering service with svc_bind() can fail, the service will be destroyed and during destruction it will try to unregister itself from rpcbind. In this case unregistration has to be skipped. Signed-off-by: Stanislav Kinsbursky Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman