Skip to content
  1. Sep 17, 2015
  3. Sep 16, 2015
  5. Sep 15, 2015
    • Jason A. Donenfeld's avatar
      x86/xen: build "Xen PV" APIC driver for domU as well · 03152d7c
      Jason A. Donenfeld authored 
      [ Upstream commit fc5fee86 ]

It turns out that a PV domU also requires the "Xen PV" APIC
driver. Otherwise, the flat driver is used and we get stuck in busy
loops that never exit, such as in this stack trace:

(gdb) target remote localhost:9999
Remote debugging using localhost:9999
__xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
56              while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY)
(gdb) bt
 #0  __xapic_wait_icr_idle () at ./arch/x86/include/asm/ipi.h:56
 #1  __default_send_IPI_shortcut (shortcut=<optimized out>,
dest=<optimized out>, vector=<optimized out>) at
./arch/x86/include/asm/ipi.h:75
 #2  apic_send_IPI_self (vector=246) at arch/x86/kernel/apic/probe_64.c:54
 #3  0xffffffff81011336 in arch_irq_work_raise () at
arch/x86/kernel/irq_work.c:47
 #4  0xffffffff8114990c in irq_work_queue (work=0xffff88000fc0e400) at
kernel/irq_work.c:100
 #5  0xffffffff8110c29d in wake_up_klogd () at kernel/printk/printk.c:2633
 #6  0xffffffff8110ca60 in vprintk_emit (facility=0, level=<optimized
out>, dict=0x0 <irq_stack_union>, dictlen=<optimized out>,
fmt=<optimized out>, args=<optimized out>)
    at kernel/printk/printk.c:1778
 #7  0xffffffff816010c8 in printk (fmt=<optimized out>) at
kernel/printk/printk.c:1868
 #8  0xffffffffc00013ea in ?? ()
 #9  0x0000000000000000 in ?? ()

Mailing-list-thread: https://lkml.org/lkml/2015/8/4/755


Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      03152d7c
    • Larry Finger's avatar
      rtlwifi: rtl8723be: Add module parameter for MSI interrupts · e01ddf27
      Larry Finger authored 
      [ Upstream commit 741e3b99

 ]

The driver code allows for the disabling of MSI interrupts; however the
module_parm line was missed and the option fails to show with modinfo.

Signed-off-by: default avatarLarry Finger <Larry.Finger@lwfinger.net>
Cc: Stable <stable@vger.kernel.org> [3.15+]
Signed-off-by: default avatarKalle Valo <kvalo@codeaurora.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      e01ddf27
    • Peter Zijlstra's avatar
      perf: Fix PERF_EVENT_IOC_PERIOD migration race · a19bd3d5
      Peter Zijlstra authored 
      [ Upstream commit c7999c6f

 ]

I ran the perf fuzzer, which triggered some WARN()s which are due to
trying to stop/restart an event on the wrong CPU.

Use the normal IPI pattern to ensure we run the code on the correct CPU.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: bad7192b

 ("perf: Fix PERF_EVENT_IOC_PERIOD to force-reset the period")
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      a19bd3d5
    • Peter Zijlstra's avatar
      perf: Fix fasync handling on inherited events · c08266ad
      Peter Zijlstra authored 
      [ Upstream commit fed66e2c

 ]

Vince reported that the fasync signal stuff doesn't work proper for
inherited events. So fix that.

Installing fasync allocates memory and sets filp->f_flags |= FASYNC,
which upon the demise of the file descriptor ensures the allocation is
freed and state is updated.

Now for perf, we can have the events stick around for a while after the
original FD is dead because of references from child events. So we
cannot copy the fasync pointer around. We can however consistently use
the parent's fasync, as that will be updated.

Reported-and-Tested-by: default avatarVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Arnaldo Carvalho deMelo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1434011521.1495.71.camel@twins


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      c08266ad
    • Bob Liu's avatar
      xen-blkback: replace work_pending with work_busy in purge_persistent_gnt() · 92eea380
      Bob Liu authored 
      [ Upstream commit 53bc7dc0

 ]

The BUG_ON() in purge_persistent_gnt() will be triggered when previous purge
work haven't finished.

There is a work_pending() before this BUG_ON, but it doesn't account if the work
is still currently running.

CC: stable@vger.kernel.org
Acked-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: default avatarBob Liu <bob.liu@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      92eea380
    • Bob Liu's avatar
      xen-blkfront: don't add indirect pages to list when !feature_persistent · 71ae6a56
      Bob Liu authored 
      [ Upstream commit 7b076750

 ]

We should consider info->feature_persistent when adding indirect page to list
info->indirect_pages, else the BUG_ON() in blkif_free() would be triggered.

When we are using persistent grants the indirect_pages list
should always be empty because blkfront has pre-allocated enough
persistent pages to fill all requests on the ring.

CC: stable@vger.kernel.org
Acked-by: default avatarRoger Pau Monné <roger.pau@citrix.com>
Signed-off-by: default avatarBob Liu <bob.liu@oracle.com>
Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      71ae6a56
    • Wanpeng Li's avatar
      mm/hwpoison: fix fail isolate hugetlbfs page w/ refcount held · 075ad72d
      Wanpeng Li authored 
      [ Upstream commit 03613808

 ]

Hugetlbfs pages will get a refcount in get_any_page() or
madvise_hwpoison() if soft offlining through madvise.  The refcount which
is held by the soft offline path should be released if we fail to isolate
hugetlbfs pages.

Fix it by reducing the refcount for both isolation success and failure.

Signed-off-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
Acked-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>	[3.9+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      075ad72d
    • Naoya Horiguchi's avatar
      mm: hugetlb: introduce page_huge_active · 08887345
      Naoya Horiguchi authored 
      [ Upstream commit bcc54222

 ]

We are not safe from calling isolate_huge_page() on a hugepage
concurrently, which can make the victim hugepage in invalid state and
results in BUG_ON().

The root problem of this is that we don't have any information on struct
page (so easily accessible) about hugepages' activeness.  Note that
hugepages' activeness means just being linked to
hstate->hugepage_activelist, which is not the same as normal pages'
activeness represented by PageActive flag.

Normal pages are isolated by isolate_lru_page() which prechecks PageLRU
before isolation, so let's do similarly for hugetlb with a new
paeg_huge_active().

set/clear_page_huge_active() should be called within hugetlb_lock.  But
hugetlb_cow() and hugetlb_no_page() don't do this, being justified because
in these functions set_page_huge_active() is called right after the
hugepage is allocated and no other thread tries to isolate it.

[akpm@linux-foundation.org: s/PageHugeActive/page_huge_active/, make it return bool]
[fengguang.wu@intel.com: set_page_huge_active() can be static]
Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hugh Dickins <hughd@google.com>
Reviewed-by: default avatarMichal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: default avatarFengguang Wu <fengguang.wu@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      08887345
    • Wanpeng Li's avatar
      mm/hwpoison: fix page refcount of unknown non LRU page · 478f59c0
      Wanpeng Li authored 
      [ Upstream commit 4f32be67

 ]

After trying to drain pages from pagevec/pageset, we try to get reference
count of the page again, however, the reference count of the page is not
reduced if the page is still not on LRU list.

Fix it by adding the put_page() to drop the page reference which is from
__get_any_page().

Signed-off-by: default avatarWanpeng Li <wanpeng.li@hotmail.com>
Acked-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>	[3.9+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      478f59c0
    • Manfred Spraul's avatar
      ipc/sem.c: update/correct memory barriers · ff12efa0
      Manfred Spraul authored 
      [ Upstream commit 3ed1f8a9

 ]

sem_lock() did not properly pair memory barriers:

!spin_is_locked() and spin_unlock_wait() are both only control barriers.
The code needs an acquire barrier, otherwise the cpu might perform read
operations before the lock test.

As no primitive exists inside <include/spinlock.h> and since it seems
noone wants another primitive, the code creates a local primitive within
ipc/sem.c.

With regards to -stable:

The change of sem_wait_array() is a bugfix, the change to sem_lock() is a
nop (just a preprocessor redefinition to improve the readability).  The
bugfix is necessary for all kernels that use sem_wait_array() (i.e.:
starting from 3.10).

Signed-off-by: default avatarManfred Spraul <manfred@colorfullife.com>
Reported-by: default avatarOleg Nesterov <oleg@redhat.com>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Kirill Tkhai <ktkhai@parallels.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: <stable@vger.kernel.org>	[3.10+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      ff12efa0
    • Herton R. Krzesinski's avatar
      ipc,sem: fix use after free on IPC_RMID after a task using same semaphore set exits · 38b50c47
      Herton R. Krzesinski authored 
      [ Upstream commit 602b8593

 ]

The current semaphore code allows a potential use after free: in
exit_sem we may free the task's sem_undo_list while there is still
another task looping through the same semaphore set and cleaning the
sem_undo list at freeary function (the task called IPC_RMID for the same
semaphore set).

For example, with a test program [1] running which keeps forking a lot
of processes (which then do a semop call with SEM_UNDO flag), and with
the parent right after removing the semaphore set with IPC_RMID, and a
kernel built with CONFIG_SLAB, CONFIG_SLAB_DEBUG and
CONFIG_DEBUG_SPINLOCK, you can easily see something like the following
in the kernel log:

   Slab corruption (Not tainted): kmalloc-64 start=ffff88003b45c1c0, len=64
   000: 6b 6b 6b 6b 6b 6b 6b 6b 00 6b 6b 6b 6b 6b 6b 6b  kkkkkkkk.kkkkkkk
   010: ff ff ff ff 6b 6b 6b 6b ff ff ff ff ff ff ff ff  ....kkkk........
   Prev obj: start=ffff88003b45c180, len=64
   000: 00 00 00 00 ad 4e ad de ff ff ff ff 5a 5a 5a 5a  .....N......ZZZZ
   010: ff ff ff ff ff ff ff ff c0 fb 01 37 00 88 ff ff  ...........7....
   Next obj: start=ffff88003b45c200, len=64
   000: 00 00 00 00 ad 4e ad de ff ff ff ff 5a 5a 5a 5a  .....N......ZZZZ
   010: ff ff ff ff ff ff ff ff 68 29 a7 3c 00 88 ff ff  ........h).<....
   BUG: spinlock wrong CPU on CPU#2, test/18028
   general protection fault: 0000 [#1] SMP
   Modules linked in: 8021q mrp garp stp llc nf_conntrack_ipv4 nf_defrag_ipv4 ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables binfmt_misc ppdev input_leds joydev parport_pc parport floppy serio_raw virtio_balloon virtio_rng virtio_console virtio_net iosf_mbi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcspkr qxl ttm drm_kms_helper drm snd_hda_codec_generic i2c_piix4 snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore crc32c_intel virtio_pci virtio_ring virtio pata_acpi ata_generic [last unloaded: speedstep_lib]
   CPU: 2 PID: 18028 Comm: test Not tainted 4.2.0-rc5+ #1
   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
   RIP: spin_dump+0x53/0xc0
   Call Trace:
     spin_bug+0x30/0x40
     do_raw_spin_unlock+0x71/0xa0
     _raw_spin_unlock+0xe/0x10
     freeary+0x82/0x2a0
     ? _raw_spin_lock+0xe/0x10
     semctl_down.clone.0+0xce/0x160
     ? __do_page_fault+0x19a/0x430
     ? __audit_syscall_entry+0xa8/0x100
     SyS_semctl+0x236/0x2c0
     ? syscall_trace_leave+0xde/0x130
     entry_SYSCALL_64_fastpath+0x12/0x71
   Code: 8b 80 88 03 00 00 48 8d 88 60 05 00 00 48 c7 c7 a0 2c a4 81 31 c0 65 8b 15 eb 40 f3 7e e8 08 31 68 00 4d 85 e4 44 8b 4b 08 74 5e <45> 8b 84 24 88 03 00 00 49 8d 8c 24 60 05 00 00 8b 53 04 48 89
   RIP  [<ffffffff810d6053>] spin_dump+0x53/0xc0
    RSP <ffff88003750fd68>
   ---[ end trace 783ebb76612867a0 ]---
   NMI watchdog: BUG: soft lockup - CPU#3 stuck for 22s! [test:18053]
   Modules linked in: 8021q mrp garp stp llc nf_conntrack_ipv4 nf_defrag_ipv4 ip6t_REJECT nf_reject_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables binfmt_misc ppdev input_leds joydev parport_pc parport floppy serio_raw virtio_balloon virtio_rng virtio_console virtio_net iosf_mbi crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcspkr qxl ttm drm_kms_helper drm snd_hda_codec_generic i2c_piix4 snd_hda_intel snd_hda_codec snd_hda_core snd_hwdep snd_seq snd_seq_device snd_pcm snd_timer snd soundcore crc32c_intel virtio_pci virtio_ring virtio pata_acpi ata_generic [last unloaded: speedstep_lib]
   CPU: 3 PID: 18053 Comm: test Tainted: G      D         4.2.0-rc5+ #1
   Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014
   RIP: native_read_tsc+0x0/0x20
   Call Trace:
     ? delay_tsc+0x40/0x70
     __delay+0xf/0x20
     do_raw_spin_lock+0x96/0x140
     _raw_spin_lock+0xe/0x10
     sem_lock_and_putref+0x11/0x70
     SYSC_semtimedop+0x7bf/0x960
     ? handle_mm_fault+0xbf6/0x1880
     ? dequeue_task_fair+0x79/0x4a0
     ? __do_page_fault+0x19a/0x430
     ? kfree_debugcheck+0x16/0x40
     ? __do_page_fault+0x19a/0x430
     ? __audit_syscall_entry+0xa8/0x100
     ? do_audit_syscall_entry+0x66/0x70
     ? syscall_trace_enter_phase1+0x139/0x160
     SyS_semtimedop+0xe/0x10
     SyS_semop+0x10/0x20
     entry_SYSCALL_64_fastpath+0x12/0x71
   Code: 47 10 83 e8 01 85 c0 89 47 10 75 08 65 48 89 3d 1f 74 ff 7e c9 c3 0f 1f 44 00 00 55 48 89 e5 e8 87 17 04 00 66 90 c9 c3 0f 1f 00 <55> 48 89 e5 0f 31 89 c1 48 89 d0 48 c1 e0 20 89 c9 48 09 c8 c9
   Kernel panic - not syncing: softlockup: hung tasks

I wasn't able to trigger any badness on a recent kernel without the
proper config debugs enabled, however I have softlockup reports on some
kernel versions, in the semaphore code, which are similar as above (the
scenario is seen on some servers running IBM DB2 which uses semaphore
syscalls).

The patch here fixes the race against freeary, by acquiring or waiting
on the sem_undo_list lock as necessary (exit_sem can race with freeary,
while freeary sets un->semid to -1 and removes the same sem_undo from
list_proc or when it removes the last sem_undo).

After the patch I'm unable to reproduce the problem using the test case
[1].

[1] Test case used below:

    #include <stdio.h>
    #include <sys/types.h>
    #include <sys/ipc.h>
    #include <sys/sem.h>
    #include <sys/wait.h>
    #include <stdlib.h>
    #include <time.h>
    #include <unistd.h>
    #include <errno.h>

    #define NSEM 1
    #define NSET 5

    int sid[NSET];

    void thread()
    {
            struct sembuf op;
            int s;
            uid_t pid = getuid();

            s = rand() % NSET;
            op.sem_num = pid % NSEM;
            op.sem_op = 1;
            op.sem_flg = SEM_UNDO;

            semop(sid[s], &op, 1);
            exit(EXIT_SUCCESS);
    }

    void create_set()
    {
            int i, j;
            pid_t p;
            union {
                    int val;
                    struct semid_ds *buf;
                    unsigned short int *array;
                    struct seminfo *__buf;
            } un;

            /* Create and initialize semaphore set */
            for (i = 0; i < NSET; i++) {
                    sid[i] = semget(IPC_PRIVATE , NSEM, 0644 | IPC_CREAT);
                    if (sid[i] < 0) {
                            perror("semget");
                            exit(EXIT_FAILURE);
                    }
            }
            un.val = 0;
            for (i = 0; i < NSET; i++) {
                    for (j = 0; j < NSEM; j++) {
                            if (semctl(sid[i], j, SETVAL, un) < 0)
                                    perror("semctl");
                    }
            }

            /* Launch threads that operate on semaphore set */
            for (i = 0; i < NSEM * NSET * NSET; i++) {
                    p = fork();
                    if (p < 0)
                            perror("fork");
                    if (p == 0)
                            thread();
            }

            /* Free semaphore set */
            for (i = 0; i < NSET; i++) {
                    if (semctl(sid[i], NSEM, IPC_RMID))
                            perror("IPC_RMID");
            }

            /* Wait for forked processes to exit */
            while (wait(NULL)) {
                    if (errno == ECHILD)
                            break;
            };
    }

    int main(int argc, char **argv)
    {
            pid_t p;

            srand(time(NULL));

            while (1) {
                    p = fork();
                    if (p < 0) {
                            perror("fork");
                            exit(EXIT_FAILURE);
                    }
                    if (p == 0) {
                            create_set();
                            goto end;
                    }

                    /* Wait for forked processes to exit */
                    while (wait(NULL)) {
                            if (errno == ECHILD)
                                    break;
                    };
            }
    end:
            return 0;
    }

[akpm@linux-foundation.org: use normal comment layout]
Signed-off-by: default avatarHerton R. Krzesinski <herton@redhat.com>
Acked-by: default avatarManfred Spraul <manfred@colorfullife.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Rafael Aquini <aquini@redhat.com>
CC: Aristeu Rozanski <aris@redhat.com>
Cc: David Jeffery <djeffery@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>

Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarSasha Levin <sasha.levin@oracle.com>
      38b50c47
  7. Sep 03, 2015
  9. Sep 01, 2015
  11. Aug 27, 2015