Commit Graph

26488 Commits

Author SHA1 Message Date
Linus Torvalds
66f8162418 Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fix from Thomas Gleixner:
 "A single fix for the new matrix allocator to prevent vector exhaustion
  by certain network drivers which allocate gazillions of unused vectors
  which cannot be put into reservation mode due to MSI and the lack of
  MSI entry masking.

  The fix/workaround is to spread the vectors across CPUs by searching
  the supplied target CPU mask for the CPU with the smallest number of
  allocated vectors"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irq/matrix: Spread interrupts on allocation
2018-01-21 10:39:58 -08:00
Linus Torvalds
ec835f8104 Merge tag 'trace-v4.15-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
 "Two more small fixes

   - The conversion of enums into their actual numbers to display in the
     event format file had an off-by-one bug, that could cause an enum
     not to be converted, and break user space parsing tools.

   - A fix to a previous fix to bring back the context recursion checks.
     The interrupt case checks for NMI, IRQ and softirq, but the softirq
     returned the same number regardless if it was set or not, although
     the logic would force it to be set if it were hit"

* tag 'trace-v4.15-rc4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Fix converting enum's from the map in trace_event_eval_update()
  ring-buffer: Fix duplicate results in mapping context to bits in recursive lock
2018-01-19 11:38:19 -08:00
Linus Torvalds
8b335c7d22 Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fix from Tejun Heo:
 "cgroup.threads should be delegatable (ie. a container should be able
  to write to it from inside) but was missing the flag.

  The change is very low risk"

* 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: make cgroup.threads delegatable
2018-01-19 11:25:17 -08:00
Linus Torvalds
a2c9c1c035 Merge branch 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fixlet from Tejun Heo:
 "One patch to add touch_nmi_watchdog() while dumping workqueue debug
  messages to avoid triggering the lockup detector spuriously.

  The change is very low risk"

* 'for-4.15-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: avoid hard lockups in show_workqueue_state()
2018-01-19 11:23:39 -08:00
Linus Torvalds
726ba84b50 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Fix BPF divides by zero, from Eric Dumazet and Alexei Starovoitov.

 2) Reject stores into bpf context via st and xadd, from Daniel
    Borkmann.

 3) Fix a memory leak in TUN, from Cong Wang.

 4) Disable RX aggregation on a specific troublesome configuration of
    r8152 in a Dell TB16b dock.

 5) Fix sw_ctx leak in tls, from Sabrina Dubroca.

 6) Fix program replacement in cls_bpf, from Daniel Borkmann.

 7) Fix uninitialized station_info structures in cfg80211, from Johannes
    Berg.

 8) Fix miscalculation of transport header offset field in flow
    dissector, from Eric Dumazet.

 9) Fix LPM tree leak on failure in mlxsw driver, from Ido Schimmel.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (29 commits)
  ibmvnic: Fix IPv6 packet descriptors
  ibmvnic: Fix IP offload control buffer
  ipv6: don't let tb6_root node share routes with other node
  ip6_gre: init dev->mtu and dev->hard_header_len correctly
  mlxsw: spectrum_router: Free LPM tree upon failure
  flow_dissector: properly cap thoff field
  fm10k: mark PM functions as __maybe_unused
  cfg80211: fix station info handling bugs
  netlink: reset extack earlier in netlink_rcv_skb
  can: af_can: canfd_rcv(): replace WARN_ONCE by pr_warn_once
  can: af_can: can_rcv(): replace WARN_ONCE by pr_warn_once
  bpf: mark dst unknown on inconsistent {s, u}bounds adjustments
  bpf: fix cls_bpf on filter replace
  Net: ethernet: ti: netcp: Fix inbound ping crash if MTU size is greater than 1500
  tls: reset crypto_info when do_tls_setsockopt_tx fails
  tls: return -EBUSY if crypto_info is already set
  tls: fix sw_ctx leak
  net/tls: Only attach to sockets in ESTABLISHED state
  net: fs_enet: do not call phy_stop() in interrupts
  r8152: disable RX aggregation on Dell TB16 dock
  ...
2018-01-19 09:30:33 -08:00
Steven Rostedt (VMware)
1ebe1eaf2f tracing: Fix converting enum's from the map in trace_event_eval_update()
Since enums do not get converted by the TRACE_EVENT macro into their values,
the event format displaces the enum name and not the value. This breaks
tools like perf and trace-cmd that need to interpret the raw binary data. To
solve this, an enum map was created to convert these enums into their actual
numbers on boot up. This is done by TRACE_EVENTS() adding a
TRACE_DEFINE_ENUM() macro.

Some enums were not being converted. This was caused by an optization that
had a bug in it.

All calls get checked against this enum map to see if it should be converted
or not, and it compares the call's system to the system that the enum map
was created under. If they match, then they call is processed.

To cut down on the number of iterations needed to find the maps with a
matching system, since calls and maps are grouped by system, when a match is
made, the index into the map array is saved, so that the next call, if it
belongs to the same system as the previous call, could start right at that
array index and not have to scan all the previous arrays.

The problem was, the saved index was used as the variable to know if this is
a call in a new system or not. If the index was zero, it was assumed that
the call is in a new system and would keep incrementing the saved index
until it found a matching system. The issue arises when the first matching
system was at index zero. The next map, if it belonged to the same system,
would then think it was the first match and increment the index to one. If
the next call belong to the same system, it would begin its search of the
maps off by one, and miss the first enum that should be converted. This left
a single enum not converted properly.

Also add a comment to describe exactly what that index was for. It took me a
bit too long to figure out what I was thinking when debugging this issue.

Link: http://lkml.kernel.org/r/717BE572-2070-4C1E-9902-9F2E0FEDA4F8@oracle.com

Cc: stable@vger.kernel.org
Fixes: 0c564a538a ("tracing: Add TRACE_DEFINE_ENUM() macro to map enums to their values")
Reported-by: Chuck Lever <chuck.lever@oracle.com>
Teste-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-18 15:53:10 -05:00
Steven Rostedt (VMware)
0164e0d7e8 ring-buffer: Fix duplicate results in mapping context to bits in recursive lock
In bringing back the context checks, the code checks first if its normal
(non-interrupt) context, and then for NMI then IRQ then softirq. The final
check is redundant. Since the if branch is only hit if the context is one of
NMI, IRQ, or SOFTIRQ, if it's not NMI or IRQ there's no reason to check if
it is SOFTIRQ. The current code returns the same result even if its not a
SOFTIRQ. Which is confusing.

  pc & SOFTIRQ_OFFSET ? 2 : RB_CTX_SOFTIRQ

Is redundant as RB_CTX_SOFTIRQ *is* 2!

Fixes: a0e3a18f4b ("ring-buffer: Bring back context level recursive checks")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-18 15:45:48 -05:00
David S. Miller
7155f8f391 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf
Daniel Borkmann says:

====================
pull-request: bpf 2018-01-18

The following pull-request contains BPF updates for your *net* tree.

The main changes are:

1) Fix a divide by zero due to wrong if (src_reg == 0) check in
   64-bit mode. Properly handle this in interpreter and mask it
   also generically in verifier to guard against similar checks
   in JITs, from Eric and Alexei.

2) Fix a bug in arm64 JIT when tail calls are involved and progs
   have different stack sizes, from Daniel.

3) Reject stores into BPF context that are not expected BPF_STX |
   BPF_MEM variant, from Daniel.

4) Mark dst reg as unknown on {s,u}bounds adjustments when the
   src reg has derived bounds from dead branches, from Daniel.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
2018-01-18 09:17:04 -05:00
Thomas Gleixner
a0c9259dc4 irq/matrix: Spread interrupts on allocation
Keith reported an issue with vector space exhaustion on a server machine
which is caused by the i40e driver allocating 168 MSI interrupts when the
driver is initialized, even when most of these interrupts are not used at
all.

The x86 vector allocation code tries to avoid the immediate allocation with
the reservation mode, but the card uses MSI and does not support MSI entry
masking, which prevents reservation mode and requires immediate vector
allocation.

The matrix allocator is a bit naive and prefers the first CPU in the
cpumask which describes the possible target CPUs for an allocation. That
results in allocating all 168 vectors on CPU0 which later causes vector
space exhaustion when the NVMe driver tries to allocate managed interrupts
on each CPU for the per CPU queues.

Avoid this by finding the CPU which has the lowest vector allocation count
to spread out the non managed interrupt accross the possible target CPUs.

Fixes: 2f75d9e1c9 ("genirq: Implement bitmap matrix allocator")
Reported-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Keith Busch <keith.busch@intel.com>
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801171557330.1777@nanos
2018-01-18 11:38:41 +01:00
Daniel Borkmann
6f16101e6a bpf: mark dst unknown on inconsistent {s, u}bounds adjustments
syzkaller generated a BPF proglet and triggered a warning with
the following:

  0: (b7) r0 = 0
  1: (d5) if r0 s<= 0x0 goto pc+0
   R0=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0
  2: (1f) r0 -= r1
   R0=inv0 R1=ctx(id=0,off=0,imm=0) R10=fp0
  verifier internal error: known but bad sbounds

What happens is that in the first insn, r0's min/max value
are both 0 due to the immediate assignment, later in the jsle
test the bounds are updated for the min value in the false
path, meaning, they yield smin_val = 1, smax_val = 0, and when
ctx pointer is subtracted from r0, verifier bails out with the
internal error and throwing a WARN since smin_val != smax_val
for the known constant.

For min_val > max_val scenario it means that reg_set_min_max()
and reg_set_min_max_inv() (which both refine existing bounds)
demonstrated that such branch cannot be taken at runtime.

In above scenario for the case where it will be taken, the
existing [0, 0] bounds are kept intact. Meaning, the rejection
is not due to a verifier internal error, and therefore the
WARN() is not necessary either.

We could just reject such cases in adjust_{ptr,scalar}_min_max_vals()
when either known scalars have smin_val != smax_val or
umin_val != umax_val or any scalar reg with bounds
smin_val > smax_val or umin_val > umax_val. However, there
may be a small risk of breakage of buggy programs, so handle
this more gracefully and in adjust_{ptr,scalar}_min_max_vals()
just taint the dst reg as unknown scalar when we see ops with
such kind of src reg.

Reported-by: syzbot+6d362cadd45dc0a12ba4@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-17 16:23:17 -08:00
Linus Torvalds
9a4ba2ab08 Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
 "A delayacct statistics correctness fix"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  delayacct: Account blkio completion on the correct task
2018-01-17 12:28:22 -08:00
Linus Torvalds
b8c22594b1 Merge branch 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Ingo Molnar:
 "Two futex fixes: a input parameters robustness fix, and futex race
  fixes"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  futex: Prevent overflow by strengthen input validation
  futex: Avoid violating the 10th rule of futex
2018-01-17 12:24:42 -08:00
Linus Torvalds
dd43f3465d Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Thomas Gleixner:
 "A one-liner fix which prevents deferrable timers becoming stale when
  the system does not switch into NOHZ mode"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  timers: Unconditionally check deferrable base
2018-01-17 11:43:42 -08:00
Daniel Borkmann
f37a8cb84c bpf: reject stores into ctx via st and xadd
Alexei found that verifier does not reject stores into context
via BPF_ST instead of BPF_STX. And while looking at it, we
also should not allow XADD variant of BPF_STX.

The context rewriter is only assuming either BPF_LDX_MEM- or
BPF_STX_MEM-type operations, thus reject anything other than
that so that assumptions in the rewriter properly hold. Add
test cases as well for BPF selftests.

Fixes: d691f9e8d4 ("bpf: allow programs to write to certain skb fields")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-16 15:04:58 -08:00
Linus Torvalds
b45a53be53 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Pull networking fixes from David Miller:

 1) Two read past end of buffer fixes in AF_KEY, from Eric Biggers.

 2) Memory leak in key_notify_policy(), from Steffen Klassert.

 3) Fix overflow with bpf arrays, from Daniel Borkmann.

 4) Fix RDMA regression with mlx5 due to mlx5 no longer using
    pci_irq_get_affinity(), from Saeed Mahameed.

 5) Missing RCU read locking in nl80211_send_iface() when it calls
    ieee80211_bss_get_ie(), from Dominik Brodowski.

 6) cfg80211 should check dev_set_name()'s return value, from Johannes
    Berg.

 7) Missing module license tag in 9p protocol, from Stephen Hemminger.

 8) Fix crash due to too small MTU in udp ipv6 sendmsg, from Mike
    Maloney.

 9) Fix endless loop in netlink extack code, from David Ahern.

10) TLS socket layer sets inverted error codes, resulting in an endless
    loop. From Robert Hering.

11) Revert openvswitch erspan tunnel support, it's mis-designed and we
    need to kill it before it goes into a real release. From William Tu.

12) Fix lan78xx failures in full speed USB mode, from Yuiko Oshino.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (54 commits)
  net, sched: fix panic when updating miniq {b,q}stats
  qed: Fix potential use-after-free in qed_spq_post()
  nfp: use the correct index for link speed table
  lan78xx: Fix failure in USB Full Speed
  sctp: do not allow the v4 socket to bind a v4mapped v6 address
  sctp: return error if the asoc has been peeled off in sctp_wait_for_sndbuf
  sctp: reinit stream if stream outcnt has been change by sinit in sendmsg
  ibmvnic: Fix pending MAC address changes
  netlink: extack: avoid parenthesized string constant warning
  ipv4: Make neigh lookup keys for loopback/point-to-point devices be INADDR_ANY
  net: Allow neigh contructor functions ability to modify the primary_key
  sh_eth: fix dumping ARSTR
  Revert "openvswitch: Add erspan tunnel support."
  net/tls: Fix inverted error codes to avoid endless loop
  ipv6: ip6_make_skb() needs to clear cork.base.dst
  sctp: avoid compiler warning on implicit fallthru
  net: ipv4: Make "ip route get" match iif lo rules again.
  netlink: extack needs to be reset each time through loop
  tipc: fix a memory leak in tipc_nl_node_get_link()
  ipv6: fix udpv6 sendmsg crash caused by too small MTU
  ...
2018-01-16 12:45:30 -08:00
Linus Torvalds
921d4f67bf Merge tag 'trace-v4.15-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:

 - Bring back context level recursive protection in ring buffer.

   The simpler counter protection failed, due to a path when tracing
   with trace_clock_global() as it could not be reentrant and depended
   on the ring buffer recursive protection to keep that from happening.

 - Prevent branch profiling when FORTIFY_SOURCE is enabled.

   It causes 50 - 60 MB in warning messages. Branch profiling should
   never be run on production systems, so there's no reason that it
   needs to be enabled with FORTIFY_SOURCE.

* tag 'trace-v4.15-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Prevent PROFILE_ALL_BRANCHES when FORTIFY_SOURCE=y
  ring-buffer: Bring back context level recursive checks
2018-01-16 12:09:36 -08:00
Josh Snyder
c96f5471ce delayacct: Account blkio completion on the correct task
Before commit:

  e33a9bba85 ("sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler")

delayacct_blkio_end() was called after context-switching into the task which
completed I/O.

This resulted in double counting: the task would account a delay both waiting
for I/O and for time spent in the runqueue.

With e33a9bba85, delayacct_blkio_end() is called by try_to_wake_up().
In ttwu, we have not yet context-switched. This is more correct, in that
the delay accounting ends when the I/O is complete.

But delayacct_blkio_end() relies on 'get_current()', and we have not yet
context-switched into the task whose I/O completed. This results in the
wrong task having its delay accounting statistics updated.

Instead of doing that, pass the task_struct being woken to delayacct_blkio_end(),
so that it can update the statistics of the correct task.

Signed-off-by: Josh Snyder <joshs@netflix.com>
Acked-by: Tejun Heo <tj@kernel.org>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: <stable@vger.kernel.org>
Cc: Brendan Gregg <bgregg@netflix.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-block@vger.kernel.org
Fixes: e33a9bba85 ("sched/core: move IO scheduling accounting from io_schedule_timeout() into scheduler")
Link: http://lkml.kernel.org/r/1513613712-571-1-git-send-email-joshs@netflix.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-01-16 03:29:36 +01:00
Randy Dunlap
68e76e034b tracing: Prevent PROFILE_ALL_BRANCHES when FORTIFY_SOURCE=y
I regularly get 50 MB - 60 MB files during kernel randconfig builds.
These large files mostly contain (many repeats of; e.g., 124,594):

In file included from ../include/linux/string.h:6:0,
                 from ../include/linux/uuid.h:20,
                 from ../include/linux/mod_devicetable.h:13,
                 from ../scripts/mod/devicetable-offsets.c:3:
../include/linux/compiler.h:64:4: warning: '______f' is static but declared in inline function 'strcpy' which is not static [enabled by default]
    ______f = {     \
    ^
../include/linux/compiler.h:56:23: note: in expansion of macro '__trace_if'
                       ^
../include/linux/string.h:425:2: note: in expansion of macro 'if'
  if (p_size == (size_t)-1 && q_size == (size_t)-1)
  ^

This only happens when CONFIG_FORTIFY_SOURCE=y and
CONFIG_PROFILE_ALL_BRANCHES=y, so prevent PROFILE_ALL_BRANCHES if
FORTIFY_SOURCE=y.

Link: http://lkml.kernel.org/r/9199446b-a141-c0c3-9678-a3f9107f2750@infradead.org

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-15 14:15:31 -05:00
Steven Rostedt (VMware)
a0e3a18f4b ring-buffer: Bring back context level recursive checks
Commit 1a149d7d3f ("ring-buffer: Rewrite trace_recursive_(un)lock() to be
simpler") replaced the context level recursion checks with a simple counter.
This would prevent the ring buffer code from recursively calling itself more
than the max number of contexts that exist (Normal, softirq, irq, nmi). But
this change caused a lockup in a specific case, which was during suspend and
resume using a global clock. Adding a stack dump to see where this occurred,
the issue was in the trace global clock itself:

  trace_buffer_lock_reserve+0x1c/0x50
  __trace_graph_entry+0x2d/0x90
  trace_graph_entry+0xe8/0x200
  prepare_ftrace_return+0x69/0xc0
  ftrace_graph_caller+0x78/0xa8
  queued_spin_lock_slowpath+0x5/0x1d0
  trace_clock_global+0xb0/0xc0
  ring_buffer_lock_reserve+0xf9/0x390

The function graph tracer traced queued_spin_lock_slowpath that was called
by trace_clock_global. This pointed out that the trace_clock_global() is not
reentrant, as it takes a spin lock. It depended on the ring buffer recursive
lock from letting that happen.

By removing the context detection and adding just a max number of allowable
recursions, it allowed the trace_clock_global() to be entered again and try
to retake the spinlock it already held, causing a deadlock.

Fixes: 1a149d7d3f ("ring-buffer: Rewrite trace_recursive_(un)lock() to be simpler")
Reported-by: David Weinehall <david.weinehall@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-01-15 12:28:06 -05:00
Thomas Gleixner
ed4bbf7910 timers: Unconditionally check deferrable base
When the timer base is checked for expired timers then the deferrable base
must be checked as well. This was missed when making the deferrable base
independent of base::nohz_active.

Fixes: ced6d5c11d ("timers: Use deferrable base independent of base::nohz_active")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org
Cc: rt@linutronix.de
2018-01-14 23:25:33 +01:00
Alexei Starovoitov
68fda450a7 bpf: fix 32-bit divide by zero
due to some JITs doing if (src_reg == 0) check in 64-bit mode
for div/mod operations mask upper 32-bits of src register
before doing the check

Fixes: 622582786c ("net: filter: x86: internal BPF JIT")
Fixes: 7a12b5031c ("sparc64: Add eBPF JIT.")
Reported-by: syzbot+48340bb518e88849e2e3@syzkaller.appspotmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2018-01-14 23:05:33 +01:00
Li Jinyue
fbe0e839d1 futex: Prevent overflow by strengthen input validation
UBSAN reports signed integer overflow in kernel/futex.c:

 UBSAN: Undefined behaviour in kernel/futex.c:2041:18
 signed integer overflow:
 0 - -2147483648 cannot be represented in type 'int'

Add a sanity check to catch negative values of nr_wake and nr_requeue.

Signed-off-by: Li Jinyue <lijinyue@huawei.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: peterz@infradead.org
Cc: dvhart@infradead.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1513242294-31786-1-git-send-email-lijinyue@huawei.com
2018-01-14 18:55:03 +01:00
Peter Zijlstra
c1e2f0eaf0 futex: Avoid violating the 10th rule of futex
Julia reported futex state corruption in the following scenario:

   waiter                                  waker                                            stealer (prio > waiter)

   futex(WAIT_REQUEUE_PI, uaddr, uaddr2,
         timeout=[N ms])
      futex_wait_requeue_pi()
         futex_wait_queue_me()
            freezable_schedule()
            <scheduled out>
                                           futex(LOCK_PI, uaddr2)
                                           futex(CMP_REQUEUE_PI, uaddr,
                                                 uaddr2, 1, 0)
                                              /* requeues waiter to uaddr2 */
                                           futex(UNLOCK_PI, uaddr2)
                                                 wake_futex_pi()
                                                    cmp_futex_value_locked(uaddr2, waiter)
                                                    wake_up_q()
           <woken by waker>
           <hrtimer_wakeup() fires,
            clears sleeper->task>
                                                                                           futex(LOCK_PI, uaddr2)
                                                                                              __rt_mutex_start_proxy_lock()
                                                                                                 try_to_take_rt_mutex() /* steals lock */
                                                                                                    rt_mutex_set_owner(lock, stealer)
                                                                                              <preempted>
         <scheduled in>
         rt_mutex_wait_proxy_lock()
            __rt_mutex_slowlock()
               try_to_take_rt_mutex() /* fails, lock held by stealer */
               if (timeout && !timeout->task)
                  return -ETIMEDOUT;
            fixup_owner()
               /* lock wasn't acquired, so,
                  fixup_pi_state_owner skipped */

   return -ETIMEDOUT;

   /* At this point, we've returned -ETIMEDOUT to userspace, but the
    * futex word shows waiter to be the owner, and the pi_mutex has
    * stealer as the owner */

   futex_lock(LOCK_PI, uaddr2)
     -> bails with EDEADLK, futex word says we're owner.

And suggested that what commit:

  73d786bd04 ("futex: Rework inconsistent rt_mutex/futex_q state")

removes from fixup_owner() looks to be just what is needed. And indeed
it is -- I completely missed that requeue_pi could also result in this
case. So we need to restore that, except that subsequent patches, like
commit:

  16ffa12d74 ("futex: Pull rt_mutex_futex_unlock() out from under hb->lock")

changed all the locking rules. Even without that, the sequence:

-               if (rt_mutex_futex_trylock(&q->pi_state->pi_mutex)) {
-                       locked = 1;
-                       goto out;
-               }

-               raw_spin_lock_irq(&q->pi_state->pi_mutex.wait_lock);
-               owner = rt_mutex_owner(&q->pi_state->pi_mutex);
-               if (!owner)
-                       owner = rt_mutex_next_owner(&q->pi_state->pi_mutex);
-               raw_spin_unlock_irq(&q->pi_state->pi_mutex.wait_lock);
-               ret = fixup_pi_state_owner(uaddr, q, owner);

already suggests there were races; otherwise we'd never have to look
at next_owner.

So instead of doing 3 consecutive wait_lock sections with who knows
what races, we do it all in a single section. Additionally, the usage
of pi_state->owner in fixup_owner() was only safe because only the
rt_mutex owner would modify it, which this additional case wrecks.

Luckily the values can only change away and not to the value we're
testing, this means we can do a speculative test and double check once
we have the wait_lock.

Fixes: 73d786bd04 ("futex: Rework inconsistent rt_mutex/futex_q state")
Reported-by: Julia Cartwright <julia@ni.com>
Reported-by: Gratian Crisan <gratian.crisan@ni.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Julia Cartwright <julia@ni.com>
Tested-by: Gratian Crisan <gratian.crisan@ni.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20171208124939.7livp7no2ov65rrc@hirez.programming.kicks-ass.net
2018-01-14 18:49:16 +01:00
Eric Dumazet
c366287ebd bpf: fix divides by zero
Divides by zero are not nice, lets avoid them if possible.

Also do_div() seems not needed when dealing with 32bit operands,
but this seems a minor detail.

Fixes: bd4cf0ed33 ("net: filter: rework/optimize internal BPF interpreter's instruction set")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2018-01-14 09:03:43 -08:00
Linus Torvalds
ed93de8420 Merge branch 'akpm' (patches from Andrew)
Merge misc fixlets from Andrew Morton:
 "4 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  tools/objtool/Makefile: don't assume sync-check.sh is executable
  kdump: write correct address of mem_section into vmcoreinfo
  kmemleak: allow to coexist with fault injection
  MAINTAINERS, nilfs2: change project home URLs
2018-01-13 11:07:55 -08:00