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percpu_ref has treated the dropping of the base reference and
switching to atomic mode as an integral operation; however, there's
nothing inherent tying the two together.
The use cases for percpu_ref have been expanding continuously. While
the current init/kill/reinit/exit model can cover a lot, the coupling
of kill/reinit with atomic/percpu mode switching is turning out to be
too restrictive for use cases where many percpu_refs are created and
destroyed back-to-back with only some of them reaching extended
operation. The coupling also makes implementing always-atomic debug
mode difficult.
This patch separates out atomic mode switching into
percpu_ref_switch_to_atomic() and reimplements
percpu_ref_kill_and_confirm() on top of it.
* The handling of __PERCPU_REF_ATOMIC and __PERCPU_REF_DEAD is now
differentiated. Among get/put operations, percpu_ref_tryget_live()
is the only one which cares about DEAD.
* percpu_ref_switch_to_atomic() can be called multiple times on the
same ref. This means that multiple @confirm_switch may get queued
up which we can't do reliably without extra memory area. This is
handled by making the later invocation synchronously wait for the
completion of the previous one. This isn't particularly desirable
but such synchronous waits shouldn't happen in most cases.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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percpu_ref will be restructured so that percpu/atomic mode switching
and reference killing are dedoupled. In preparation, add
PCPU_REF_DEAD and PCPU_REF_ATOMIC_DEAD which is OR of ATOMIC and DEAD.
For now, ATOMIC and DEAD are changed together and all PCPU_REF_ATOMIC
uses are converted to PCPU_REF_ATOMIC_DEAD without causing any
behavior changes.
percpu_ref_init() now specifies an explicit alignment when allocating
the percpu counters so that the pointer has enough unused low bits to
accomodate the flags. Note that one flag was fine as min alignment
for percpu memory is 2 bytes but two flags are already too many for
the natural alignment of unsigned longs on archs like cris and m68k.
v2: The original patch had BUILD_BUG_ON() which triggers if unsigned
long's alignment isn't enough to accomodate the flags, which
triggered on cris and m64k. percpu_ref_init() updated to specify
the required alignment explicitly. Reported by Fengguang.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
Cc: kbuild test robot <fengguang.wu@intel.com>
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percpu_ref will be restructured so that percpu/atomic mode switching
and reference killing are dedoupled. In preparation, do the following
renames.
* percpu_ref->confirm_kill -> percpu_ref->confirm_switch
* __PERCPU_REF_DEAD -> __PERCPU_REF_ATOMIC
* __percpu_ref_alive() -> __ref_is_percpu()
This patch is pure rename and doesn't introduce any functional
changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
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percpu_ref uses pcpu_ prefix for internal stuff and percpu_ for
externally visible ones. This is the same convention used in the
percpu allocator implementation. It works fine there but percpu_ref
doesn't have too much internal-only stuff and scattered usages of
pcpu_ prefix are confusing than helpful.
This patch replaces all pcpu_ prefixes with percpu_. This is pure
rename and there's no functional change. Note that PCPU_REF_DEAD is
renamed to __PERCPU_REF_DEAD to signify that the flag is internal.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
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* Some comments became stale. Updated.
* percpu_ref_tryget() unnecessarily initializes @ret. Removed.
* A blank line removed from percpu_ref_kill_rcu().
* Explicit function name in a WARN format string replaced with __func__.
* WARN_ON() in percpu_ref_reinit() converted to WARN_ON_ONCE().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
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percpu_ref is gonna go through restructuring. Move
percpu_ref_reinit() after percpu_ref_kill_and_confirm(). This will
make later changes easier to follow and result in cleaner
organization.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Kent Overstreet <kmo@daterainc.com>
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probe"
This reverts commit 0a30288da1aec914e158c2d7a3482a85f632750f, which
was a temporary fix for SCSI blk-mq stall issue. The following
patches will fix the issue properly by introducing atomic mode to
percpu_ref.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block into for-3.18
This is to receive 0a30288da1ae ("blk-mq, percpu_ref: implement a
kludge for SCSI blk-mq stall during probe") which implements
__percpu_ref_kill_expedited() to work around SCSI blk-mq stall. The
commit reverted and patches to implement proper fix will be added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@lst.de>
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blk-mq uses percpu_ref for its usage counter which tracks the number
of in-flight commands and used to synchronously drain the queue on
freeze. percpu_ref shutdown takes measureable wallclock time as it
involves a sched RCU grace period. This means that draining a blk-mq
takes measureable wallclock time. One would think that this shouldn't
matter as queue shutdown should be a rare event which takes place
asynchronously w.r.t. userland.
Unfortunately, SCSI probing involves synchronously setting up and then
tearing down a lot of request_queues back-to-back for non-existent
LUNs. This means that SCSI probing may take more than ten seconds
when scsi-mq is used.
This will be properly fixed by implementing a mechanism to keep
q->mq_usage_counter in atomic mode till genhd registration; however,
that involves rather big updates to percpu_ref which is difficult to
apply late in the devel cycle (v3.17-rc6 at the moment). As a
stop-gap measure till the proper fix can be implemented in the next
cycle, this patch introduces __percpu_ref_kill_expedited() and makes
blk_mq_freeze_queue() use it. This is heavy-handed but should work
for testing the experimental SCSI blk-mq implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Christoph Hellwig <hch@infradead.org>
Link: http://lkml.kernel.org/g/20140919113815.GA10791@lst.de
Fixes: add703fda981 ("blk-mq: use percpu_ref for mq usage count")
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jens Axboe <axboe@kernel.dk>
Tested-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
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Conflicts:
arch/mips/net/bpf_jit.c
drivers/net/can/flexcan.c
Both the flexcan and MIPS bpf_jit conflicts were cases of simple
overlapping changes.
Signed-off-by: David S. Miller <davem@davemloft.net>
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Pull networking fixes from David Miller:
1) If the user gives us a msg_namelen of 0, don't try to interpret
anything pointed to by msg_name. From Ani Sinha.
2) Fix some bnx2i/bnx2fc randconfig compilation errors.
The gist of the issue is that we firstly have drivers that span both
SCSI and networking. And at the top of that chain of dependencies
we have things like SCSI_FC_ATTRS and SCSI_NETLINK which are
selected.
But since select is a sledgehammer and ignores dependencies,
everything to select's SCSI_FC_ATTRS and/or SCSI_NETLINK has to also
explicitly select their dependencies and so on and so forth.
Generally speaking 'select' is supposed to only be used for child
nodes, those which have no dependencies of their own. And this
whole chain of dependencies in the scsi layer violates that rather
strongly.
So just make SCSI_NETLINK depend upon it's dependencies, and so on
and so forth for the things selecting it (either directly or
indirectly).
From Anish Bhatt and Randy Dunlap.
3) Fix generation of blackhole routes in IPSEC, from Steffen Klassert.
4) Actually notice netdev feature changes in rtl_open() code, from
Hayes Wang.
5) Fix divide by zero in bond enslaving, from Nikolay Aleksandrov.
6) Missing memory barrier in sunvnet driver, from David Stevens.
7) Don't leave anycast addresses around when ipv6 interface is
destroyed, from Sabrina Dubroca.
8) Don't call efx_{arch}_filter_sync_rx_mode before addr_list_lock is
initialized in SFC driver, from Edward Cree.
9) Fix missing DMA error checking in 3c59x, from Neal Horman.
10) Openvswitch doesn't emit OVS_FLOW_CMD_NEW notifications accidently,
fix from Samuel Gauthier.
11) pch_gbe needs to select NET_PTP_CLASSIFY otherwise we can get a
build error.
12) Fix macvlan regression wherein we stopped emitting
broadcast/multicast frames over software devices. From Nicolas
Dichtel.
13) Fix infiniband bug due to unintended overflow of skb->cb[], from
Eric Dumazet. And add an assertion so this doesn't happen again.
14) dm9000_parse_dt() should return error pointers, not NULL. From
Tobias Klauser.
15) IP tunneling code uses this_cpu_ptr() in preemptible contexts, fix
from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (87 commits)
net: bcmgenet: call bcmgenet_dma_teardown in bcmgenet_fini_dma
net: bcmgenet: fix TX reclaim accounting for fragments
ipv4: do not use this_cpu_ptr() in preemptible context
dm9000: Return an ERR_PTR() in all error conditions of dm9000_parse_dt()
r8169: fix an if condition
r8152: disable ALDPS
ipoib: validate struct ipoib_cb size
net: sched: shrink struct qdisc_skb_cb to 28 bytes
tg3: Work around HW/FW limitations with vlan encapsulated frames
macvlan: allow to enqueue broadcast pkt on virtual device
pch_gbe: 'select' NET_PTP_CLASSIFY.
scsi: Use 'depends' with LIBFC instead of 'select'.
openvswitch: restore OVS_FLOW_CMD_NEW notifications
genetlink: add function genl_has_listeners()
lib: rhashtable: remove second linux/log2.h inclusion
net: allow macvlans to move to net namespace
3c59x: Fix bad offset spec in skb_frag_dma_map
3c59x: Add dma error checking and recovery
sparc: bpf_jit: fix support for ldx/stx mem and SKF_AD_VLAN_TAG
can: at91_can: add missing prepare and unprepare of the clock
...
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old gcc 4.2 used by avr32 architecture produces warnings:
lib/test_bpf.c:1741: warning: integer constant is too large for 'long' type
lib/test_bpf.c:1741: warning: integer constant is too large for 'long' type
lib/test_bpf.c: In function '__run_one':
lib/test_bpf.c:1897: warning: 'ret' may be used uninitialized in this function
silence these warnings.
Fixes: 02ab695bb37e ("net: filter: add "load 64-bit immediate" eBPF instruction")
Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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percpu_ref is currently based on ints and the number of refs it can
cover is (1 << 31). This makes it impossible to use a percpu_ref to
count memory objects or pages on 64bit machines as it may overflow.
This forces those users to somehow aggregate the references before
contributing to the percpu_ref which is often cumbersome and sometimes
challenging to get the same level of performance as using the
percpu_ref directly.
While using ints for the percpu counters makes them pack tighter on
64bit machines, the possible gain from using ints instead of longs is
extremely small compared to the overall gain from per-cpu operation.
This patch makes percpu_ref based on longs so that it can be used to
directly count memory objects or pages.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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percpu_ref's WARN messages can be a lot more helpful by indicating
who's the culprit. Make them report the release function that the
offending percpu-refcount is associated with. This should make it a
lot easier to track down the reported invalid refcnting operations.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <kmo@daterainc.com>
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linux/log2.h was included twice.
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>
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overwritten
Currently in the event of a stack overrun a call to schedule()
does not check for this type of corruption. This corruption is
often silent and can go unnoticed. However once the corrupted
region is examined at a later stage, the outcome is undefined
and often results in a sporadic page fault which cannot be
handled.
This patch checks for a stack overrun and takes appropriate
action since the damage is already done, there is no point
in continuing.
Signed-off-by: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: aneesh.kumar@linux.vnet.ibm.com
Cc: dzickus@redhat.com
Cc: bmr@redhat.com
Cc: jcastillo@redhat.com
Cc: oleg@redhat.com
Cc: riel@redhat.com
Cc: prarit@redhat.com
Cc: jgh@redhat.com
Cc: minchan@kernel.org
Cc: mpe@ellerman.id.au
Cc: tglx@linutronix.de
Cc: rostedt@goodmis.org
Cc: hannes@cmpxchg.org
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lubomir Rintel <lkundrak@v3.sk>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1410527779-8133-4-git-send-email-atomlin@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Provide a function to convert a buffer of binary data into an unterminated
ascii hex string representation of that data.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
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It used to be an ad-hoc hack defined by the x86 version of
<asm/bitops.h> that enabled a couple of library routines to know whether
an integer multiply is faster than repeated shifts and additions.
This just makes it use the real Kconfig system instead, and makes x86
(which was the only architecture that did this) select the option.
NOTE! Even for x86, this really is kind of wrong. If we cared, we would
probably not enable this for builds optimized for netburst (P4), where
shifts-and-adds are generally faster than multiplies. This patch does
*not* change that kind of logic, though, it is purely a syntactic change
with no code changes.
This was triggered by the fact that we have other places that really
want to know "do I want to expand multiples by constants by hand or
not", particularly the hash generation code.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This fixes CVE-2014-3631.
It is possible for an associative array to end up with a shortcut node at the
root of the tree if there are more than fan-out leaves in the tree, but they
all crowd into the same slot in the lowest level (ie. they all have the same
first nibble of their index keys).
When assoc_array_gc() returns back up the tree after scanning some leaves, it
can fall off of the root and crash because it assumes that the back pointer
from a shortcut (after label ascend_old_tree) must point to a normal node -
which isn't true of a shortcut node at the root.
Should we find we're ascending rootwards over a shortcut, we should check to
see if the backpointer is zero - and if it is, we have completed the scan.
This particular bug cannot occur if the root node is not a shortcut - ie. if
you have fewer than 17 keys in a keyring or if you have at least two keys that
sit into separate slots (eg. a keyring and a non keyring).
This can be reproduced by:
ring=`keyctl newring bar @s`
for ((i=1; i<=18; i++)); do last_key=`keyctl newring foo$i $ring`; done
keyctl timeout $last_key 2
Doing this:
echo 3 >/proc/sys/kernel/keys/gc_delay
first will speed things up.
If we do fall off of the top of the tree, we get the following oops:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
IP: [<ffffffff8136cea7>] assoc_array_gc+0x2f7/0x540
PGD dae15067 PUD cfc24067 PMD 0
Oops: 0000 [#1] SMP
Modules linked in: xt_nat xt_mark nf_conntrack_netbios_ns nf_conntrack_broadcast ip6t_rpfilter ip6t_REJECT xt_conntrack ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables ip6table_ni
CPU: 0 PID: 26011 Comm: kworker/0:1 Not tainted 3.14.9-200.fc20.x86_64 #1
Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
Workqueue: events key_garbage_collector
task: ffff8800918bd580 ti: ffff8800aac14000 task.ti: ffff8800aac14000
RIP: 0010:[<ffffffff8136cea7>] [<ffffffff8136cea7>] assoc_array_gc+0x2f7/0x540
RSP: 0018:ffff8800aac15d40 EFLAGS: 00010206
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff8800aaecacc0
RDX: ffff8800daecf440 RSI: 0000000000000001 RDI: ffff8800aadc2bc0
RBP: ffff8800aac15da8 R08: 0000000000000001 R09: 0000000000000003
R10: ffffffff8136ccc7 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000070 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000018 CR3: 00000000db10d000 CR4: 00000000000006f0
Stack:
ffff8800aac15d50 0000000000000011 ffff8800aac15db8 ffffffff812e2a70
ffff880091a00600 0000000000000000 ffff8800aadc2bc3 00000000cd42c987
ffff88003702df20 ffff88003702dfa0 0000000053b65c09 ffff8800aac15fd8
Call Trace:
[<ffffffff812e2a70>] ? keyring_detect_cycle_iterator+0x30/0x30
[<ffffffff812e3e75>] keyring_gc+0x75/0x80
[<ffffffff812e1424>] key_garbage_collector+0x154/0x3c0
[<ffffffff810a67b6>] process_one_work+0x176/0x430
[<ffffffff810a744b>] worker_thread+0x11b/0x3a0
[<ffffffff810a7330>] ? rescuer_thread+0x3b0/0x3b0
[<ffffffff810ae1a8>] kthread+0xd8/0xf0
[<ffffffff810ae0d0>] ? insert_kthread_work+0x40/0x40
[<ffffffff816ffb7c>] ret_from_fork+0x7c/0xb0
[<ffffffff810ae0d0>] ? insert_kthread_work+0x40/0x40
Code: 08 4c 8b 22 0f 84 bf 00 00 00 41 83 c7 01 49 83 e4 fc 41 83 ff 0f 4c 89 65 c0 0f 8f 5a fe ff ff 48 8b 45 c0 4d 63 cf 49 83 c1 02 <4e> 8b 34 c8 4d 85 f6 0f 84 be 00 00 00 41 f6 c6 01 0f 84 92
RIP [<ffffffff8136cea7>] assoc_array_gc+0x2f7/0x540
RSP <ffff8800aac15d40>
CR2: 0000000000000018
---[ end trace 1129028a088c0cbd ]---
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
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add BPF_LD_IMM64 instruction to load 64-bit immediate value into a register.
All previous instructions were 8-byte. This is first 16-byte instruction.
Two consecutive 'struct bpf_insn' blocks are interpreted as single instruction:
insn[0].code = BPF_LD | BPF_DW | BPF_IMM
insn[0].dst_reg = destination register
insn[0].imm = lower 32-bit
insn[1].code = 0
insn[1].imm = upper 32-bit
All unused fields must be zero.
Classic BPF has similar instruction: BPF_LD | BPF_W | BPF_IMM
which loads 32-bit immediate value into a register.
x64 JITs it as single 'movabsq %rax, imm64'
arm64 may JIT as sequence of four 'movk x0, #imm16, lsl #shift' insn
Note that old eBPF programs are binary compatible with new interpreter.
It helps eBPF programs load 64-bit constant into a register with one
instruction instead of using two registers and 4 instructions:
BPF_MOV32_IMM(R1, imm32)
BPF_ALU64_IMM(BPF_LSH, R1, 32)
BPF_MOV32_IMM(R2, imm32)
BPF_ALU64_REG(BPF_OR, R1, R2)
User space generated programs will use this instruction to load constants only.
To tell kernel that user space needs a pointer the _pseudo_ variant of
this instruction may be added later, which will use extra bits of encoding
to indicate what type of pointer user space is asking kernel to provide.
For example 'off' or 'src_reg' fields can be used for such purpose.
src_reg = 1 could mean that user space is asking kernel to validate and
load in-kernel map pointer.
src_reg = 2 could mean that user space needs readonly data section pointer
src_reg = 3 could mean that user space needs a pointer to per-cpu local data
All such future pseudo instructions will not be carrying the actual pointer
as part of the instruction, but rather will be treated as a request to kernel
to provide one. The kernel will verify the request_for_a_pointer, then
will drop _pseudo_ marking and will store actual internal pointer inside
the instruction, so the end result is the interpreter and JITs never
see pseudo BPF_LD_IMM64 insns and only operate on generic BPF_LD_IMM64 that
loads 64-bit immediate into a register. User space never operates on direct
pointers and verifier can easily recognize request_for_pointer vs other
instructions.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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This patch fix spelling typo found in DocBook/kernel-api.xml.
It is because the file is generated from the source comments,
I have to fix the comments in source codes.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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Percpu allocator now supports allocation mask. Add @gfp to
percpu_ref_init() so that !GFP_KERNEL allocation masks can be used
with percpu_refs too.
This patch doesn't make any functional difference.
v2: blk-mq conversion was missing. Updated.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Nicholas A. Bellinger <nab@linux-iscsi.org>
Cc: Jens Axboe <axboe@kernel.dk>
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Percpu allocator now supports allocation mask. Add @gfp to
[flex_]proportions init functions so that !GFP_KERNEL allocation masks
can be used with them too.
This patch doesn't make any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
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Percpu allocator now supports allocation mask. Add @gfp to
percpu_counter_init() so that !GFP_KERNEL allocation masks can be used
with percpu_counters too.
We could have left percpu_counter_init() alone and added
percpu_counter_init_gfp(); however, the number of users isn't that
high and introducing _gfp variants to all percpu data structures would
be quite ugly, so let's just do the conversion. This is the one with
the most users. Other percpu data structures are a lot easier to
convert.
This patch doesn't make any functional difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: "David S. Miller" <davem@davemloft.net>
Cc: x86@kernel.org
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
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percpu_counter is scheduled to grow @gfp support to allow atomic
initialization. This patch makes percpu_counters_lock irq-safe so
that it can be safely used from atomic contexts.
Signed-off-by: Tejun Heo <tj@kernel.org>
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With eBPF getting more extended and exposure to user space is on it's way,
hardening the memory range the interpreter uses to steer its command flow
seems appropriate. This patch moves the to be interpreted bytecode to
read-only pages.
In case we execute a corrupted BPF interpreter image for some reason e.g.
caused by an attacker which got past a verifier stage, it would not only
provide arbitrary read/write memory access but arbitrary function calls
as well. After setting up the BPF interpreter image, its contents do not
change until destruction time, thus we can setup the image on immutable
made pages in order to mitigate modifications to that code. The idea
is derived from commit 314beb9bcabf ("x86: bpf_jit_comp: secure bpf jit
against spraying attacks").
This is possible because bpf_prog is not part of sk_filter anymore.
After setup bpf_prog cannot be altered during its life-time. This prevents
any modifications to the entire bpf_prog structure (incl. function/JIT
image pointer).
Every eBPF program (including classic BPF that are migrated) have to call
bpf_prog_select_runtime() to select either interpreter or a JIT image
as a last setup step, and they all are being freed via bpf_prog_free(),
including non-JIT. Therefore, we can easily integrate this into the
eBPF life-time, plus since we directly allocate a bpf_prog, we have no
performance penalty.
Tested with seccomp and test_bpf testsuite in JIT/non-JIT mode and manual
inspection of kernel_page_tables. Brad Spengler proposed the same idea
via Twitter during development of this patch.
Joint work with Hannes Frederic Sowa.
Suggested-by: Brad Spengler <spender@grsecurity.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Although rhashtable library allows user to specify a quiet big size
for user's created hash table, the table may be shrunk to a
very small size - HASH_MIN_SIZE(4) after object is removed from
the table at the first time. Subsequently, even if the total amount
of objects saved in the table is quite lower than user's initial
setting in a long time, the hash table size is still dynamically
adjusted by rhashtable_shrink() or rhashtable_expand() each time
object is inserted or removed from the table. However, as
synchronize_rcu() has to be called when table is shrunk or
expanded by the two functions, we should permit user to set the
minimum table size through configuring the minimum number of shifts
according to user specific requirement, avoiding these expensive
actions of shrinking or expanding because of calling synchronize_rcu().
Signed-off-by: Ying Xue <ying.xue@windriver.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
No need for rht_dereference() from rhashtable_destroy() since the
existing callers don't hold the mutex when invoking this function
from:
1) Netlink, this is called in case of memory allocation errors in the
initialization path, no nl_sk_hash_lock is held.
2) Netfilter, this is called from the rcu callback, no nfnl_lock is
held either.
I think it's reasonable to assume that the caller has to make sure
that no hash resizing may happen before releasing the bucket array.
Therefore, the caller should be responsible for releasing this in a
safe way, document this to make people aware of it.
This resolves a rcu lockdep splat in nft_hash:
===============================
[ INFO: suspicious RCU usage. ]
3.16.0+ #178 Not tainted
-------------------------------
lib/rhashtable.c:596 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 1
1 lock held by ksoftirqd/2/18:
#0: (rcu_callback){......}, at: [<ffffffff810918fd>] rcu_process_callbacks+0x27e/0x4c7
stack backtrace:
CPU: 2 PID: 18 Comm: ksoftirqd/2 Not tainted 3.16.0+ #178
Hardware name: LENOVO 23259H1/23259H1, BIOS G2ET32WW (1.12 ) 05/30/2012
0000000000000001 ffff88011706bb68 ffffffff8143debc 0000000000000000
ffff880117062610 ffff88011706bb98 ffffffff81077515 ffff8800ca041a50
0000000000000004 ffff8800ca386480 ffff8800ca041a00 ffff88011706bbb8
Call Trace:
[<ffffffff8143debc>] dump_stack+0x4e/0x68
[<ffffffff81077515>] lockdep_rcu_suspicious+0xfa/0x103
[<ffffffff81228b1b>] rhashtable_destroy+0x46/0x52
[<ffffffffa06f21a7>] nft_hash_destroy+0x73/0x82 [nft_hash]
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Acked-by: Thomas Graf <tgraf@suug.ch>
|
|
An edit script should be considered inaccessible by a function once it has
called assoc_array_apply_edit() or assoc_array_cancel_edit().
However, assoc_array_gc() is accessing the edit script just after the
gc_complete: label.
Reported-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Andreea-Cristina Bernat <bernat.ada@gmail.com>
cc: shemming@brocade.com
cc: paulmck@linux.vnet.ibm.com
Cc: stable@vger.kernel.org
Signed-off-by: James Morris <james.l.morris@oracle.com>
|
|
s/fromstack/from stack
Signed-off-by: Horia Geanta <horia.geanta@freescale.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
|
|
I was puzzled why /proc/$$/stack had disappeared, until I figured out I
had disabled the last debug option that did a 'select STACKTRACE'. This
patch makes the option show up at config time, so it can be enabled
without enabling any of the more heavyweight debug options.
Signed-off-by: Dave Jones <davej@redhat.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
We really don't want distro's enabling this in their kernels. Try and
make that more clear.
Signed-off-by: Rob Clark <robdclark@gmail.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
|
|
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Thomas Graf <tgraf@suug.ch>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
|
|
'shift by register' operations are supported by eBPF interpreter, but were
accidently left out of x64 JIT compiler. Fix it and add a testcase.
Reported-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Fixes: 622582786c9e ("net: filter: x86: internal BPF JIT")
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
This patch addresses a couple of minor items, mostly addesssing
prandom_bytes(): 1) prandom_bytes{,_state}() should use size_t
for length arguments, 2) We can use put_unaligned() when filling
the array instead of open coding it [ perhaps some archs will
further benefit from their own arch specific implementation when
GCC cannot make up for it ], 3) Fix a typo, 4) Better use unsigned
int as type for getting the arch seed, 5) Make use of
prandom_u32_max() for timer slack.
Regarding the change to put_unaligned(), callers of prandom_bytes()
which internally invoke prandom_bytes_state(), don't bother as
they expect the array to be filled randomly and don't have any
control of the internal state what-so-ever (that's also why we
have periodic reseeding there, etc), so they really don't care.
Now for the direct callers of prandom_bytes_state(), which
are solely located in test cases for MTD devices, that is,
drivers/mtd/tests/{oobtest.c,pagetest.c,subpagetest.c}:
These tests basically fill a test write-vector through
prandom_bytes_state() with an a-priori defined seed each time
and write that to a MTD device. Later on, they set up a read-vector
and read back that blocks from the device. So in the verification
phase, the write-vector is being re-setup [ so same seed and
prandom_bytes_state() called ], and then memcmp()'ed against the
read-vector to check if the data is the same.
Akinobu, Lothar and I also tested this patch and it runs through
the 3 relevant MTD test cases w/o any errors on the nandsim device
(simulator for MTD devs) for x86_64, ppc64, ARM (i.MX28, i.MX53
and i.MX6):
# modprobe nandsim first_id_byte=0x20 second_id_byte=0xac \
third_id_byte=0x00 fourth_id_byte=0x15
# modprobe mtd_oobtest dev=0
# modprobe mtd_pagetest dev=0
# modprobe mtd_subpagetest dev=0
We also don't have any users depending directly on a particular
result of the PRNG (except the PRNG self-test itself), and that's
just fine as it e.g. allowed us easily to do things like upgrading
from taus88 to taus113.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Tested-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Lothar Waßmann <LW@KARO-electronics.de>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Pull networking fixes from David Miller:
"I'm sending this out, in particular, to get the iwlwifi fix
propagated:
1) Fix build due to missing include in i40e driver, from Lucas
Tanure.
2) Memory leak in openvswitch port allocation, from Chirstoph Jaeger.
3) Check DMA mapping errors in myri10ge, from Stanislaw Gruszka.
4) Fix various deadlock scenerios in sunvnet driver, from Sowmini
Varadhan.
5) Fix cxgb4i build failures with incompatible Kconfig settings of
the driver vs ipv6, from Anish Bhatt.
6) Fix generation of ACK packet timestamps in the presence of TSO
which will be split up, from Willem de Bruijn.
7) Don't enable sched scan in iwlwifi driver, it causes firmware
crashes in some revisions. From Emmanuel Grumbach.
8) Revert a macvlan simplification that causes crashes.
9) Handle RTT calculations properly in the presence of repair'd SKBs,
from Andrey Vagin.
10) SIT tunnel lookup uses wrong device index in compares, from
Shmulik Ladkani.
11) Handle MTU reductions in TCP properly for ipv4 mapped ipv6
sockets, from Neal Cardwell.
12) Add missing annotations in rhashtable code, from Thomas Graf.
13) Fix false interpretation of two RTOs as being from the same TCP
loss event in the FRTO code, from Neal Cardwell"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (42 commits)
netlink: Annotate RCU locking for seq_file walker
rhashtable: fix annotations for rht_for_each_entry_rcu()
rhashtable: unexport and make rht_obj() static
rhashtable: RCU annotations for next pointers
tcp: fix ssthresh and undo for consecutive short FRTO episodes
tcp: don't allow syn packets without timestamps to pass tcp_tw_recycle logic
tcp: fix tcp_release_cb() to dispatch via address family for mtu_reduced()
sit: Fix ipip6_tunnel_lookup device matching criteria
net: ethernet: ibm: ehea: Remove duplicate object from Makefile
net: xgene: Check negative return value of xgene_enet_get_ring_size()
tcp: don't use timestamp from repaired skb-s to calculate RTT (v2)
net: xilinx: Remove .owner field for driver
Revert "macvlan: simplify the structure port"
iwlwifi: mvm: disable scheduled scan to prevent firmware crash
xen-netback: remove loop waiting function
xen-netback: don't stop dealloc kthread too early
xen-netback: move NAPI add/remove calls
xen-netback: fix debugfs entry creation
xen-netback: fix debugfs write length check
net-timestamp: fix missing tcp fragmentation cases
...
|
|
No need to export rht_obj(), all inner to outer object translations
occur internally. It was intended to be used with rht_for_each() which
now primarily serves as the iterator for rhashtable_remove_pprev() to
effectively flush and free the full table.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Properly annotate next pointers as access is RCU protected in
the lookup path.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kbuild updates from Michal Marek:
- make clean also considers $(extra-m) and $(extra-) to be consistent
- cleanup and fixes in scripts/Makefile.host
- allow to override the name of the Python 2 executable with make
PYTHON=... (only needed for ia64 in practice)
- option to split debugingo into *.dwo files to save disk space if the
compiler supports it (CONFIG_DEBUG_INFO_SPLIT)
- option to use dwarf4 debuginfo if the compiler supports it
(CONFIG_DEBUG_INFO_DWARF4)
- fix for disabling certain warnings with clang
- fix for unneeded rebuild with dash when a command contains
backslashes
* 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
kbuild: Fix handling of backslashes in *.cmd files
kbuild, LLVMLinux: Supress warnings unless W=1-3
Kbuild: Add a option to enable dwarf4 v2
kbuild: Support split debug info v4
kbuild: allow to override Python command name
kbuild: clean-up and bug fix of scripts/Makefile.host
kbuild: clean up scripts/Makefile.host
kbuild: drop shared library support from Makefile.host
kbuild: fix a bug of C++ host program handling
kbuild: fix a typo in scripts/Makefile.host
scripts/Makefile.clean: clean also $(extra-m) and $(extra-)
|
|
Pull block driver changes from Jens Axboe:
"Nothing out of the ordinary here, this pull request contains:
- A big round of fixes for bcache from Kent Overstreet, Slava Pestov,
and Surbhi Palande. No new features, just a lot of fixes.
- The usual round of drbd updates from Andreas Gruenbacher, Lars
Ellenberg, and Philipp Reisner.
- virtio_blk was converted to blk-mq back in 3.13, but now Ming Lei
has taken it one step further and added support for actually using
more than one queue.
- Addition of an explicit SG_FLAG_Q_AT_HEAD for block/bsg, to
compliment the the default behavior of adding to the tail of the
queue. From Douglas Gilbert"
* 'for-3.17/drivers' of git://git.kernel.dk/linux-block: (86 commits)
bcache: Drop unneeded blk_sync_queue() calls
bcache: add mutex lock for bch_is_open
bcache: Correct printing of btree_gc_max_duration_ms
bcache: try to set b->parent properly
bcache: fix memory corruption in init error path
bcache: fix crash with incomplete cache set
bcache: Fix more early shutdown bugs
bcache: fix use-after-free in btree_gc_coalesce()
bcache: Fix an infinite loop in journal replay
bcache: fix crash in bcache_btree_node_alloc_fail tracepoint
bcache: bcache_write tracepoint was crashing
bcache: fix typo in bch_bkey_equal_header
bcache: Allocate bounce buffers with GFP_NOWAIT
bcache: Make sure to pass GFP_WAIT to mempool_alloc()
bcache: fix uninterruptible sleep in writeback thread
bcache: wait for buckets when allocating new btree root
bcache: fix crash on shutdown in passthrough mode
bcache: fix lockdep warnings on shutdown
bcache allocator: send discards with correct size
bcache: Fix to remove the rcu_sched stalls.
...
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|
Rewrite generic atomic support to only require cmpxchg(), generate all
other primitives from that.
Furthermore reduce the endless repetition for all these primitives to
a few CPP macros. This way we get more for less lines.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20140508135852.940119622@infradead.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
The queued rwlock does not support the use of recursive read-lock in
the process context. With changes in the lockdep code to check and
disallow recursive read-lock, it is also necessary for the locking
selftest to be updated to change the process context recursive read
locking results from SUCCESS to FAILURE for rwlock.
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1407345722-61615-3-git-send-email-Waiman.Long@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Specifically:
Documentation/locking/lockdep-design.txt
Documentation/locking/lockstat.txt
Documentation/locking/mutex-design.txt
Documentation/locking/rt-mutex-design.txt
Documentation/locking/rt-mutex.txt
Documentation/locking/spinlocks.txt
Documentation/locking/ww-mutex-design.txt
Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: jason.low2@hp.com
Cc: aswin@hp.com
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Mason <clm@fb.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: David Airlie <airlied@linux.ie>
Cc: Davidlohr Bueso <davidlohr@hp.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jason Low <jason.low2@hp.com>
Cc: Josef Bacik <jbacik@fusionio.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Lubomir Rintel <lkundrak@v3.sk>
Cc: Masanari Iida <standby24x7@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: fengguang.wu@intel.com
Link: http://lkml.kernel.org/r/1406752916-3341-6-git-send-email-davidlohr@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
|
|
Rather than have architectures #define ARCH_HAS_SG_CHAIN in an
architecture specific scatterlist.h, make it a proper Kconfig option and
use that instead. At same time, remove the header files are are now
mostly useless and just include asm-generic/scatterlist.h.
[sfr@canb.auug.org.au: powerpc files now need asm/dma.h]
Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de> [x86]
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> [powerpc]
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Now with 64bit bzImage and kexec tools, we support ramdisk that size is
bigger than 2g, as we could put it above 4G.
Found compressed initramfs image could not be decompressed properly. It
turns out that image length is int during decompress detection, and it
will become < 0 when length is more than 2G. Furthermore, during
decompressing len as int is used for inbuf count, that has problem too.
Change len to long, that should be ok as on 32 bit platform long is
32bits.
Tested with following compressed initramfs image as root with kexec.
gzip, bzip2, xz, lzma, lzop, lz4.
run time for populate_rootfs():
size name Nehalem-EX Westmere-EX Ivybridge-EX
9034400256 root_img : 26s 24s 30s
3561095057 root_img.lz4 : 28s 27s 27s
3459554629 root_img.lzo : 29s 29s 28s
3219399480 root_img.gz : 64s 62s 49s
2251594592 root_img.xz : 262s 260s 183s
2226366598 root_img.lzma: 386s 376s 277s
2901482513 root_img.bz2 : 635s 599s
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rashika Kheria <rashika.kheria@gmail.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Cc: P J P <ppandit@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: "Daniel M. Weeks" <dan@danweeks.net>
Cc: Alexandre Courbot <acourbot@nvidia.com>
Cc: Jan Beulich <JBeulich@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
During testing initrd (>2G) support, find decompress/lz4 does not work
with initrd at all.
decompress_* should support:
1. inbuf[]/outbuf[] for kernel preboot.
2. inbuf[]/flush() for initramfs
3. fill()/flush() for initrd.
in the unlz4 does not handle case 3, as input len is passed as 0, and it
failed in first try.
Fix that add one extra if (fill) checking, and get out if EOF from the
fill().
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Kyungsik Lee <kyungsik.lee@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Use BUG_ON(x) rather than if(x) BUG();
The semantic patch that fixes this problem is as follows:
// <smpl>
@@ identifier x; @@
-if (!x) BUG();
+BUG_ON(!x);
// </smpl>
Signed-off-by: Himangi Saraogi <himangi774@gmail.com>
Acked-by: Julia Lawall <julia.lawall@lip6.fr>
Cc: Stefani Seibold <stefani@seibold.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
In case 1, it passes down the BLACK color from G to p and u, and maintains
the color of n. By doing so, it maintains the black height of the
sub-tree.
While in the comment, it marks the color of n to BLACK. This is a typo
and not consistents with the code.
This patch fixs this typo in comment.
Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: Michel Lespinasse <walken@google.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
I'm working on address sanitizer project for kernel. Recently we
started experiments with stack instrumentation, to detect out-of-bounds
read/write bugs on stack.
Just after booting I've hit out-of-bounds read on stack in idr_for_each
(and in __idr_remove_all as well):
struct idr_layer **paa = &pa[0];
while (id >= 0 && id <= max) {
...
while (n < fls(id)) {
n += IDR_BITS;
p = *--paa; <--- here we are reading pa[-1] value.
}
}
Despite the fact that after this dereference we are exiting out of loop
and never use p, such behaviour is undefined and should be avoided.
Fix this by moving pointer derference to the beggining of the loop,
right before we will use it.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Alexey Preobrazhensky <preobr@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|