commit ec183d2 upstream.

Fixes segmentation fault using, for instance:

  (gdb) run record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Starting program: /home/acme/bin/perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls
  Missing separate debuginfos, use: dnf debuginfo-install glibc-2.22-7.fc23.x86_64
  [Thread debugging using libthread_db enabled]
  Using host libthread_db library "/lib64/libthread_db.so.1".

 Program received signal SIGSEGV, Segmentation fault.
  0 x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  (gdb) bt
  #0  0x00000000004b9ea5 in tracepoint_error (e=0x0, err=13, sys=0x19b1370 "sched", name=0x19a5d00 "sched_switch") at util/parse-events.c:410
  #1  0x00000000004b9fc5 in add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:433
  #2  0x00000000004ba334 in add_tracepoint_event (list=0x19a5d20, idx=0x7fffffffb8c0, sys_name=0x19b1370 "sched", evt_name=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:498
  #3  0x00000000004bb699 in parse_events_add_tracepoint (list=0x19a5d20, idx=0x7fffffffb8c0, sys=0x19b1370 "sched", event=0x19a5d00 "sched_switch", err=0x0, head_config=0x0)
      at util/parse-events.c:936
  #4  0x00000000004f6eda in parse_events_parse (_data=0x7fffffffb8b0, scanner=0x19a49d0) at util/parse-events.y:391
  #5  0x00000000004bc8e5 in parse_events__scanner (str=0x663ff2 "sched:sched_switch", data=0x7fffffffb8b0, start_token=258) at util/parse-events.c:1361
  #6  0x00000000004bca57 in parse_events (evlist=0x19a5220, str=0x663ff2 "sched:sched_switch", err=0x0) at util/parse-events.c:1401
  #7  0x0000000000518d5f in perf_evlist__can_select_event (evlist=0x19a3b90, str=0x663ff2 "sched:sched_switch") at util/record.c:253
  #8  0x0000000000553c42 in intel_pt_track_switches (evlist=0x19a3b90) at arch/x86/util/intel-pt.c:364
  #9  0x00000000005549d1 in intel_pt_recording_options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at arch/x86/util/intel-pt.c:664
  #10 0x000000000051e076 in auxtrace_record__options (itr=0x19a2c40, evlist=0x19a3b90, opts=0x8edf68 <record+232>) at util/auxtrace.c:539
  #11 0x0000000000433368 in cmd_record (argc=1, argv=0x7fffffffde60, prefix=0x0) at builtin-record.c:1264
  #12 0x000000000049bec2 in run_builtin (p=0x8fa2a8 <commands+168>, argc=5, argv=0x7fffffffde60) at perf.c:390
  #13 0x000000000049c12a in handle_internal_command (argc=5, argv=0x7fffffffde60) at perf.c:451
  #14 0x000000000049c278 in run_argv (argcp=0x7fffffffdcbc, argv=0x7fffffffdcb0) at perf.c:495
  #15 0x000000000049c60a in main (argc=5, argv=0x7fffffffde60) at perf.c:618
(gdb)

Intel PT attempts to find the sched:sched_switch tracepoint but that seg
faults if tracefs is not readable, because the error reporting structure
is null, as errors are not reported when automatically adding
tracepoints.  Fix by checking before using.

Committer note:

This doesn't take place in a kernel that supports
perf_event_attr.context_switch, that is the default way that will be
used for tracking context switches, only in older kernels, like 4.2, in
a machine with Intel PT (e.g. Broadwell) for non-priviledged users.

Further info from a similar patch by Wang:

The error is in tracepoint_error: it assumes the 'e' parameter is valid.

However, there are many situation a parse_event() can be called without
parse_events_error. See result of

  $ grep 'parse_events(.*NULL)' ./tools/perf/ -r'

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Tong Zhang <ztong@vt.edu>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 1965817 ("perf tools: Enhance parsing events tracepoint error output")
Link: http://lkml.kernel.org/r/1453809921-24596-2-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

BugLink: http://bugs.launchpad.net/bugs/1621113

commit adc8a43 upstream.

Done, because line6_stream_stop() locks and calls line6_unlink_audio_urbs(),
which in turn invokes audio_out_callback(), which tries to lock 2nd time.

Fixes:

=============================================
[ INFO: possible recursive locking detected ]
4.4.15+ #15 Not tainted
---------------------------------------------
mplayer/3591 is trying to acquire lock:
 (&(&line6pcm->out.lock)->rlock){-.-...}, at: [<bfa27655>] audio_out_callback+0x70/0x110 [snd_usb_line6]

but task is already holding lock:
 (&(&line6pcm->out.lock)->rlock){-.-...}, at: [<bfa26aad>] line6_stream_stop+0x24/0x5c [snd_usb_line6]

other info that might help us debug this:
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&(&line6pcm->out.lock)->rlock);
  lock(&(&line6pcm->out.lock)->rlock);

 *** DEADLOCK ***

 May be due to missing lock nesting notation

3 locks held by mplayer/3591:
 #0:  (snd_pcm_link_rwlock){.-.-..}, at: [<bf8d49a7>] snd_pcm_stream_lock+0x1e/0x40 [snd_pcm]
 #1:  (&(&substream->self_group.lock)->rlock){-.-...}, at: [<bf8d49af>] snd_pcm_stream_lock+0x26/0x40 [snd_pcm]
 #2:  (&(&line6pcm->out.lock)->rlock){-.-...}, at: [<bfa26aad>] line6_stream_stop+0x24/0x5c [snd_usb_line6]

stack backtrace:
CPU: 0 PID: 3591 Comm: mplayer Not tainted 4.4.15+ #15
Hardware name: Generic AM33XX (Flattened Device Tree)
[<c0015d85>] (unwind_backtrace) from [<c001253d>] (show_stack+0x11/0x14)
[<c001253d>] (show_stack) from [<c02f1bdf>] (dump_stack+0x8b/0xac)
[<c02f1bdf>] (dump_stack) from [<c0076f43>] (__lock_acquire+0xc8b/0x1780)
[<c0076f43>] (__lock_acquire) from [<c007810d>] (lock_acquire+0x99/0x1c0)
[<c007810d>] (lock_acquire) from [<c06171e7>] (_raw_spin_lock_irqsave+0x3f/0x4c)
[<c06171e7>] (_raw_spin_lock_irqsave) from [<bfa27655>] (audio_out_callback+0x70/0x110 [snd_usb_line6])
[<bfa27655>] (audio_out_callback [snd_usb_line6]) from [<c04294db>] (__usb_hcd_giveback_urb+0x53/0xd0)
[<c04294db>] (__usb_hcd_giveback_urb) from [<c046388d>] (musb_giveback+0x3d/0x98)
[<c046388d>] (musb_giveback) from [<c04647f5>] (musb_urb_dequeue+0x6d/0x114)
[<c04647f5>] (musb_urb_dequeue) from [<c042ac11>] (usb_hcd_unlink_urb+0x39/0x98)
[<c042ac11>] (usb_hcd_unlink_urb) from [<bfa26a87>] (line6_unlink_audio_urbs+0x6a/0x6c [snd_usb_line6])
[<bfa26a87>] (line6_unlink_audio_urbs [snd_usb_line6]) from [<bfa26acb>] (line6_stream_stop+0x42/0x5c [snd_usb_line6])
[<bfa26acb>] (line6_stream_stop [snd_usb_line6]) from [<bfa26fe7>] (snd_line6_trigger+0xb6/0xf4 [snd_usb_line6])
[<bfa26fe7>] (snd_line6_trigger [snd_usb_line6]) from [<bf8d47b7>] (snd_pcm_do_stop+0x36/0x38 [snd_pcm])
[<bf8d47b7>] (snd_pcm_do_stop [snd_pcm]) from [<bf8d462f>] (snd_pcm_action_single+0x22/0x40 [snd_pcm])
[<bf8d462f>] (snd_pcm_action_single [snd_pcm]) from [<bf8d46f9>] (snd_pcm_action+0xac/0xb0 [snd_pcm])
[<bf8d46f9>] (snd_pcm_action [snd_pcm]) from [<bf8d4b61>] (snd_pcm_drop+0x38/0x64 [snd_pcm])
[<bf8d4b61>] (snd_pcm_drop [snd_pcm]) from [<bf8d6233>] (snd_pcm_common_ioctl1+0x7fe/0xbe8 [snd_pcm])
[<bf8d6233>] (snd_pcm_common_ioctl1 [snd_pcm]) from [<bf8d6779>] (snd_pcm_playback_ioctl1+0x15c/0x51c [snd_pcm])
[<bf8d6779>] (snd_pcm_playback_ioctl1 [snd_pcm]) from [<bf8d6b59>] (snd_pcm_playback_ioctl+0x20/0x28 [snd_pcm])
[<bf8d6b59>] (snd_pcm_playback_ioctl [snd_pcm]) from [<c016714b>] (do_vfs_ioctl+0x3af/0x5c8)

Fixes: 63e20df ('ALSA: line6: Reorganize PCM stream handling')
Reviewed-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Andrej Krutak <dev@andree.sk>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1637520

commit b6bc1c7 upstream.

Function ib_create_qp() was failing to return an error when
rdma_rw_init_mrs() fails, causing a crash further down in ib_create_qp()
when trying to dereferece the qp pointer which was actually a negative
errno.

The crash:

crash> log|grep BUG
[  136.458121] BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
crash> bt
PID: 3736   TASK: ffff8808543215c0  CPU: 2   COMMAND: "kworker/u64:2"
 #0 [ffff88084d323340] machine_kexec at ffffffff8105fbb0
 #1 [ffff88084d3233b0] __crash_kexec at ffffffff81116758
 #2 [ffff88084d323480] crash_kexec at ffffffff8111682d
 #3 [ffff88084d3234b0] oops_end at ffffffff81032bd6
 #4 [ffff88084d3234e0] no_context at ffffffff8106e431
 #5 [ffff88084d323530] __bad_area_nosemaphore at ffffffff8106e610
 #6 [ffff88084d323590] bad_area_nosemaphore at ffffffff8106e6f4
 #7 [ffff88084d3235a0] __do_page_fault at ffffffff8106ebdc
 #8 [ffff88084d323620] do_page_fault at ffffffff8106f057
 #9 [ffff88084d323660] page_fault at ffffffff816e3148
    [exception RIP: ib_create_qp+427]
    RIP: ffffffffa02554fb  RSP: ffff88084d323718  RFLAGS: 00010246
    RAX: 0000000000000004  RBX: fffffffffffffff4  RCX: 000000018020001f
    RDX: ffff880830997fc0  RSI: 0000000000000001  RDI: ffff88085f407200
    RBP: ffff88084d323778   R8: 0000000000000001   R9: ffffea0020bae210
    R10: ffffea0020bae218  R11: 0000000000000001  R12: ffff88084d3237c8
    R13: 00000000fffffff4  R14: ffff880859fa5000  R15: ffff88082eb89800
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
#10 [ffff88084d323780] rdma_create_qp at ffffffffa0782681 [rdma_cm]
#11 [ffff88084d3237b0] nvmet_rdma_create_queue_ib at ffffffffa07c43f3 [nvmet_rdma]
#12 [ffff88084d323860] nvmet_rdma_alloc_queue at ffffffffa07c5ba9 [nvmet_rdma]
#13 [ffff88084d323900] nvmet_rdma_queue_connect at ffffffffa07c5c96 [nvmet_rdma]
#14 [ffff88084d323980] nvmet_rdma_cm_handler at ffffffffa07c6450 [nvmet_rdma]
#15 [ffff88084d3239b0] iw_conn_req_handler at ffffffffa0787480 [rdma_cm]
#16 [ffff88084d323a60] cm_conn_req_handler at ffffffffa0775f06 [iw_cm]
#17 [ffff88084d323ab0] process_event at ffffffffa0776019 [iw_cm]
#18 [ffff88084d323af0] cm_work_handler at ffffffffa0776170 [iw_cm]
#19 [ffff88084d323cb0] process_one_work at ffffffff810a1483
#20 [ffff88084d323d90] worker_thread at ffffffff810a211d
#21 [ffff88084d323ec0] kthread at ffffffff810a6c5c
#22 [ffff88084d323f50] ret_from_fork at ffffffff816e1ebf

Fixes: 632bc3f ("IB/core, RDMA RW API: Do not exceed QP SGE send limit")
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1642606

commit bbe097f upstream.

Since commit c32b5bc ("ARM: dts: at91: Fix USB endpoint nodes"),
atmel_usba_udc fails with:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 0 at include/linux/usb/gadget.h:405
ecm_do_notify+0x188/0x1a0
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 4.7.0+ #15
Hardware name: Atmel SAMA5
[<c010ccfc>] (unwind_backtrace) from [<c010a7ec>] (show_stack+0x10/0x14)
[<c010a7ec>] (show_stack) from [<c0115c10>] (__warn+0xe4/0xfc)
[<c0115c10>] (__warn) from [<c0115cd8>] (warn_slowpath_null+0x20/0x28)
[<c0115cd8>] (warn_slowpath_null) from [<c04377ac>] (ecm_do_notify+0x188/0x1a0)
[<c04377ac>] (ecm_do_notify) from [<c04379a4>] (ecm_set_alt+0x74/0x1ac)
[<c04379a4>] (ecm_set_alt) from [<c042f74c>] (composite_setup+0xfc0/0x19f8)
[<c042f74c>] (composite_setup) from [<c04356e8>] (usba_udc_irq+0x8f4/0xd9c)
[<c04356e8>] (usba_udc_irq) from [<c013ec9c>] (handle_irq_event_percpu+0x9c/0x158)
[<c013ec9c>] (handle_irq_event_percpu) from [<c013ed80>] (handle_irq_event+0x28/0x3c)
[<c013ed80>] (handle_irq_event) from [<c01416d4>] (handle_fasteoi_irq+0xa0/0x168)
[<c01416d4>] (handle_fasteoi_irq) from [<c013e3f8>] (generic_handle_irq+0x24/0x34)
[<c013e3f8>] (generic_handle_irq) from [<c013e640>] (__handle_domain_irq+0x54/0xa8)
[<c013e640>] (__handle_domain_irq) from [<c010b214>] (__irq_svc+0x54/0x70)
[<c010b214>] (__irq_svc) from [<c0107eb0>] (arch_cpu_idle+0x38/0x3c)
[<c0107eb0>] (arch_cpu_idle) from [<c0137300>] (cpu_startup_entry+0x9c/0xdc)
[<c0137300>] (cpu_startup_entry) from [<c0900c40>] (start_kernel+0x354/0x360)
[<c0900c40>] (start_kernel) from [<20008078>] (0x20008078)
---[ end trace e7cf9dcebf4815a6 ]---

Fixes: c32b5bc ("ARM: dts: at91: Fix USB endpoint nodes")
Reported-by: Richard Genoud <richard.genoud@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1650607

[ Upstream commit 0eab121 ]

Prior to commit c0371da ("put iov_iter into msghdr") in v3.19, there
was no check that the iovec contained enough bytes for an ICMP header,
and the read loop would walk across neighboring stack contents. Since the
iov_iter conversion, bad arguments are noticed, but the returned error is
EFAULT. Returning EINVAL is a clearer error and also solves the problem
prior to v3.19.

This was found using trinity with KASAN on v3.18:

BUG: KASAN: stack-out-of-bounds in memcpy_fromiovec+0x60/0x114 at addr ffffffc071077da0
Read of size 8 by task trinity-c2/9623
page:ffffffbe034b9a08 count:0 mapcount:0 mapping:          (null) index:0x0
flags: 0x0()
page dumped because: kasan: bad access detected
CPU: 0 PID: 9623 Comm: trinity-c2 Tainted: G    BU         3.18.0-dirty #15
Hardware name: Google Tegra210 Smaug Rev 1,3+ (DT)
Call trace:
[<ffffffc000209c98>] dump_backtrace+0x0/0x1ac arch/arm64/kernel/traps.c:90
[<ffffffc000209e54>] show_stack+0x10/0x1c arch/arm64/kernel/traps.c:171
[<     inline     >] __dump_stack lib/dump_stack.c:15
[<ffffffc000f18dc4>] dump_stack+0x7c/0xd0 lib/dump_stack.c:50
[<     inline     >] print_address_description mm/kasan/report.c:147
[<     inline     >] kasan_report_error mm/kasan/report.c:236
[<ffffffc000373dcc>] kasan_report+0x380/0x4b8 mm/kasan/report.c:259
[<     inline     >] check_memory_region mm/kasan/kasan.c:264
[<ffffffc00037352c>] __asan_load8+0x20/0x70 mm/kasan/kasan.c:507
[<ffffffc0005b9624>] memcpy_fromiovec+0x5c/0x114 lib/iovec.c:15
[<     inline     >] memcpy_from_msg include/linux/skbuff.h:2667
[<ffffffc000ddeba0>] ping_common_sendmsg+0x50/0x108 net/ipv4/ping.c:674
[<ffffffc000dded30>] ping_v4_sendmsg+0xd8/0x698 net/ipv4/ping.c:714
[<ffffffc000dc91dc>] inet_sendmsg+0xe0/0x12c net/ipv4/af_inet.c:749
[<     inline     >] __sock_sendmsg_nosec net/socket.c:624
[<     inline     >] __sock_sendmsg net/socket.c:632
[<ffffffc000cab61c>] sock_sendmsg+0x124/0x164 net/socket.c:643
[<     inline     >] SYSC_sendto net/socket.c:1797
[<ffffffc000cad270>] SyS_sendto+0x178/0x1d8 net/socket.c:1761

CVE-2016-8399

Reported-by: Qidan He <i@flanker017.me>
Fixes: c319b4d ("net: ipv4: add IPPROTO_ICMP socket kind")
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

… registration

BugLink: http://bugs.launchpad.net/bugs/1674325

http://patchwork.ozlabs.org/patch/740414/

drv->cpumask defaults to cpu_possible_mask in __cpuidle_driver_init().
This breaks cpuidle on powernv where sysfs files are not created for
cpus in cpu_possible_mask that cannot be hot-added.

Trying cpuidle_register_device() on cpu without sysfs node will
cause crash like:

cpu 0xf: Vector: 380 (Data SLB Access) at [c000000ff1503490]
    pc: c00000000022c8bc: string+0x34/0x60
    lr: c00000000022ed78: vsnprintf+0x284/0x42c
    sp: c000000ff1503710
   msr: 9000000000009033
   dar: 6000000060000000
  current = 0xc000000ff1480000
  paca    = 0xc00000000fe82d00   softe: 0        irq_happened: 0x01
    pid   = 1, comm = swapper/8
Linux version 4.11.0-rc2 (sv@sagarika) (gcc version 4.9.4 (Buildroot 2017.02-00004-gc28573e) ) #15 SMP Fri Mar 17 19:32:02 IST 2017
enter ? for help
[link register   ] c00000000022ed78 vsnprintf+0x284/0x42c
[c000000ff1503710] c00000000022ebb8 vsnprintf+0xc4/0x42c (unreliable)
[c000000ff1503800] c00000000022ef40 vscnprintf+0x20/0x44
[c000000ff1503830] c0000000000ab61c vprintk_emit+0x94/0x2cc
[c000000ff15038a0] c0000000000acc9c vprintk_func+0x60/0x74
[c000000ff15038c0] c000000000619694 printk+0x38/0x4c
[c000000ff15038e0] c000000000224950 kobject_get+0x40/0x60
[c000000ff1503950] c00000000022507c kobject_add_internal+0x60/0x2c4
[c000000ff15039e0] c000000000225350 kobject_init_and_add+0x70/0x78
[c000000ff1503a60] c00000000053c288 cpuidle_add_sysfs+0x9c/0xe0
[c000000ff1503ae0] c00000000053aeac cpuidle_register_device+0xd4/0x12c
[c000000ff1503b30] c00000000053b108 cpuidle_register+0x98/0xcc
[c000000ff1503bc0] c00000000085eaf0 powernv_processor_idle_init+0x140/0x1e0
[c000000ff1503c60] c00000000000cd60 do_one_initcall+0xc0/0x15c
[c000000ff1503d20] c000000000833e84 kernel_init_freeable+0x1a0/0x25c
[c000000ff1503dc0] c00000000000d478 kernel_init+0x24/0x12c
[c000000ff1503e30] c00000000000b564 ret_from_kernel_thread+0x5c/0x78

This patch fixes the issue by passing correct cpumask from
powernv-cpuidle driver.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Acked-by: Brad Figg <brad.figg@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1675789

[ Upstream commit 45caeaa ]

As Eric Dumazet pointed out this also needs to be fixed in IPv6.
v2: Contains the IPv6 tcp/Ipv6 dccp patches as well.

We have seen a few incidents lately where a dst_enty has been freed
with a dangling TCP socket reference (sk->sk_dst_cache) pointing to that
dst_entry. If the conditions/timings are right a crash then ensues when the
freed dst_entry is referenced later on. A Common crashing back trace is:

 #8 [] page_fault at ffffffff8163e648
    [exception RIP: __tcp_ack_snd_check+74]
.
.
 #9 [] tcp_rcv_established at ffffffff81580b64
#10 [] tcp_v4_do_rcv at ffffffff8158b54a
#11 [] tcp_v4_rcv at ffffffff8158cd02
#12 [] ip_local_deliver_finish at ffffffff815668f4
#13 [] ip_local_deliver at ffffffff81566bd9
#14 [] ip_rcv_finish at ffffffff8156656d
#15 [] ip_rcv at ffffffff81566f06
#16 [] __netif_receive_skb_core at ffffffff8152b3a2
#17 [] __netif_receive_skb at ffffffff8152b608
#18 [] netif_receive_skb at ffffffff8152b690
#19 [] vmxnet3_rq_rx_complete at ffffffffa015eeaf [vmxnet3]
#20 [] vmxnet3_poll_rx_only at ffffffffa015f32a [vmxnet3]
#21 [] net_rx_action at ffffffff8152bac2
#22 [] __do_softirq at ffffffff81084b4f
#23 [] call_softirq at ffffffff8164845c
#24 [] do_softirq at ffffffff81016fc5
#25 [] irq_exit at ffffffff81084ee5
#26 [] do_IRQ at ffffffff81648ff8

Of course it may happen with other NIC drivers as well.

It's found the freed dst_entry here:

 224 static bool tcp_in_quickack_mode(struct sock *sk)↩
 225 {↩
 226 ▹       const struct inet_connection_sock *icsk = inet_csk(sk);↩
 227 ▹       const struct dst_entry *dst = __sk_dst_get(sk);↩
 228 ↩
 229 ▹       return (dst && dst_metric(dst, RTAX_QUICKACK)) ||↩
 230 ▹       ▹       (icsk->icsk_ack.quick && !icsk->icsk_ack.pingpong);↩
 231 }↩

But there are other backtraces attributed to the same freed dst_entry in
netfilter code as well.

All the vmcores showed 2 significant clues:

- Remote hosts behind the default gateway had always been redirected to a
different gateway. A rtable/dst_entry will be added for that host. Making
more dst_entrys with lower reference counts. Making this more probable.

- All vmcores showed a postitive LockDroppedIcmps value, e.g:

LockDroppedIcmps                  267

A closer look at the tcp_v4_err() handler revealed that do_redirect() will run
regardless of whether user space has the socket locked. This can result in a
race condition where the same dst_entry cached in sk->sk_dst_entry can be
decremented twice for the same socket via:

do_redirect()->__sk_dst_check()-> dst_release().

Which leads to the dst_entry being prematurely freed with another socket
pointing to it via sk->sk_dst_cache and a subsequent crash.

To fix this skip do_redirect() if usespace has the socket locked. Instead let
the redirect take place later when user space does not have the socket
locked.

The dccp/IPv6 code is very similar in this respect, so fixing it there too.

As Eric Garver pointed out the following commit now invalidates routes. Which
can set the dst->obsolete flag so that ipv4_dst_check() returns null and
triggers the dst_release().

Fixes: ceb3320 ("ipv4: Kill routes during PMTU/redirect updates.")
Cc: Eric Garver <egarver@redhat.com>
Cc: Hannes Sowa <hsowa@redhat.com>
Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1677600

commit 4dfce57 upstream.

There have been several reports over the years of NULL pointer
dereferences in xfs_trans_log_inode during xfs_fsr processes,
when the process is doing an fput and tearing down extents
on the temporary inode, something like:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
PID: 29439  TASK: ffff880550584fa0  CPU: 6   COMMAND: "xfs_fsr"
    [exception RIP: xfs_trans_log_inode+0x10]
 #9 [ffff8800a57bbbe0] xfs_bunmapi at ffffffffa037398e [xfs]
#10 [ffff8800a57bbce8] xfs_itruncate_extents at ffffffffa0391b29 [xfs]
#11 [ffff8800a57bbd88] xfs_inactive_truncate at ffffffffa0391d0c [xfs]
#12 [ffff8800a57bbdb8] xfs_inactive at ffffffffa0392508 [xfs]
#13 [ffff8800a57bbdd8] xfs_fs_evict_inode at ffffffffa035907e [xfs]
#14 [ffff8800a57bbe00] evict at ffffffff811e1b67
#15 [ffff8800a57bbe28] iput at ffffffff811e23a5
#16 [ffff8800a57bbe58] dentry_kill at ffffffff811dcfc8
#17 [ffff8800a57bbe88] dput at ffffffff811dd06c
#18 [ffff8800a57bbea8] __fput at ffffffff811c823b
#19 [ffff8800a57bbef0] ____fput at ffffffff811c846e
#20 [ffff8800a57bbf00] task_work_run at ffffffff81093b27
#21 [ffff8800a57bbf30] do_notify_resume at ffffffff81013b0c
#22 [ffff8800a57bbf50] int_signal at ffffffff8161405d

As it turns out, this is because the i_itemp pointer, along
with the d_ops pointer, has been overwritten with zeros
when we tear down the extents during truncate.  When the in-core
inode fork on the temporary inode used by xfs_fsr was originally
set up during the extent swap, we mistakenly looked at di_nextents
to determine whether all extents fit inline, but this misses extents
generated by speculative preallocation; we should be using if_bytes
instead.

This mistake corrupts the in-memory inode, and code in
xfs_iext_remove_inline eventually gets bad inputs, causing
it to memmove and memset incorrect ranges; this became apparent
because the two values in ifp->if_u2.if_inline_ext[1] contained
what should have been in d_ops and i_itemp; they were memmoved due
to incorrect array indexing and then the original locations
were zeroed with memset, again due to an array overrun.

Fix this by properly using i_df.if_bytes to determine the number
of extents, not di_nextents.

Thanks to dchinner for looking at this with me and spotting the
root cause.

[nborisov: backported to 4.4]

Cc: stable@vger.kernel.org
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--
 fs/xfs/xfs_bmap_util.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>