The __latent_entropy gcc attribute can be used only on functions and
variables. If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents. The variable must
be an integer, an integer array type or a structure with integer fields.
These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).
To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).
Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.
Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
Pull ARM fixes from Russell King:
"Three relatively small fixes for ARM:
- Roger noticed that dma_max_pfn() was calculating the upper limit
wrongly, by adding the PFN offset of memory twice.
- A fix from Robin to correct parsing of MPIDR values when the
address size is larger than one BE32 unit.
- A fix from Srinivas to ensure that we do not rely on the boot
loader (or previous Linux kernel) setting the translation table
base register a certain way in the decompressor, which can lead to
crashes"
* 'fixes' of git://git.armlinux.org.uk/~rmk/linux-arm:
ARM: 8618/1: decompressor: reset ttbcr fields to use TTBR0 on ARMv7
ARM: 8617/1: dma: fix dma_max_pfn()
ARM: 8616/1: dt: Respect property size when parsing CPUs
If the bootloader uses the long descriptor format and jumps to
kernel decompressor code, TTBCR may not be in a right state.
Before enabling the MMU, it is required to clear the TTBCR.PD0
field to use TTBR0 for translation table walks.
The commit dbece45894 ("ARM: 7501/1: decompressor:
reset ttbcr for VMSA ARMv7 cores") does the reset of TTBCR.N, but
doesn't consider all the bits for the size of TTBCR.N.
Clear TTBCR.PD0 field and reset all the three bits of TTBCR.N to
indicate the use of TTBR0 and the correct base address width.
Fixes: dbece45894 ("ARM: 7501/1: decompressor: reset ttbcr for VMSA ARMv7 cores")
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Srinivas Ramana <sramana@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Pull x86 fixes from Thomas Gleixner:
"The last regression fixes for 4.8 final:
- Two patches addressing the fallout of the CR4 optimizations which
caused CR4-less machines to fail.
- Fix the VDSO build on big endian machines
- Take care of FPU initialization if no CPUID is available otherwise
task struct size ends up being zero
- Fix up context tracking in case load_gs_index fails"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry/64: Fix context tracking state warning when load_gs_index fails
x86/boot: Initialize FPU and X86_FEATURE_ALWAYS even if we don't have CPUID
x86/vdso: Fix building on big endian host
x86/boot: Fix another __read_cr4() case on 486
x86/init: Fix cr4_init_shadow() on CR4-less machines
Pull sparc fixes from David Miller:
1) Fix section mismatches in some builds, from Paul Gortmaker.
2) Need to count huge zero page mappings when doing TSB sizing, from
Mike Kravetz.
3) Fix handing of cpu_possible_mask when nr_cpus module option is
specified, from Atish Patra.
4) Don't allocate irq stacks until nr_irqs has been processed, also
from Atish Patra.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
sparc64: Fix non-SMP build.
sparc64: Fix irq stack bootmem allocation.
sparc64: Fix cpu_possible_mask if nr_cpus is set
sparc64 mm: Fix more TSB sizing issues
sparc64: fix section mismatch in find_numa_latencies_for_group
Pull networking fixes from David Miller:
1) Fix wrong TCP checksums on MTU probing when checksum offloading is
disabled, from Douglas Caetano dos Santos.
2) Fix qdisc backlog updates in qfq and sfb schedulers, from Cong Wang.
3) Route lookup flow key protocol value is wrong in ip6gre_xmit_other(),
fix from Lance Richardson.
4) Scheduling while atomic in multicast routing code of ipv4 and ipv6,
fix from Nikolay Aleksandrov.
5) Fix packet alignment in fec driver, from Eric Nelson.
6) Fix perf regression in sctp due to struct layout and cache misses,
from Xin Long.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
sctp: fix the issue sctp_diag uses lock_sock in rcu_read_lock
sctp: change to check peer prsctp_capable when using prsctp polices
sctp: remove prsctp_param from sctp_chunk
sctp: move sent_count to the memory hole in sctp_chunk
tg3: Avoid NULL pointer dereference in tg3_io_error_detected()
act_ife: Fix false encoding
act_ife: Fix external mac header on encode
VSOCK: Don't dec ack backlog twice for rejected connections
Revert "net: ethernet: bcmgenet: use phydev from struct net_device"
net: fec: align IP header in hardware
net: fec: remove QUIRK_HAS_RACC from i.mx27
net: fec: remove QUIRK_HAS_RACC from i.mx25
ipmr, ip6mr: fix scheduling while atomic and a deadlock with ipmr_get_route
ip6_gre: fix flowi6_proto value in ip6gre_xmit_other()
tcp: fix a compile error in DBGUNDO()
tcp: fix wrong checksum calculation on MTU probing
sch_sfb: keep backlog updated with qlen
sch_qfq: keep backlog updated with qlen
can: dev: fix deadlock reported after bus-off
When discovering the number of VPEs per core, smp_num_siblings will be
incorrect for kernels built without support for the MIPS MultiThreading
(MT) ASE running on systems which implement said ASE. This leads to
accesses to VPEs in secondary cores being performed incorrectly since
mips_cm_vp_id calculates the wrong ID to write to the local "other"
registers. Fix this by examining the number of VPEs in the core as
reported by the CM.
This patch presumes that the number of VPEs will be the same in each
core of the system. As this path only applies to systems with CM version
2.5 or lower, and this property is true of all such known systems, this
is likely to be fine but is described in a comment for good measure.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/14338/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Pull SCSI fix from James Bottomley:
"One final fix before 4.8.
There was a memory leak triggered by turning scsi mq off due to the
fact that we assume on host release that the already running hosts
weren't mq based because that's the state of the global flag (even
though they were).
Fix it by tracking this on a per host host basis"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: Avoid that toggling use_blk_mq triggers a memory leak
Pull input fix from Dmitry Torokhov:
"One small change to make joydev (which is used by older games) to bind
to devices that export Z axis but not X or Y (such as TRC rudder)"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: joydev - recognize devices with Z axis as joysticks
Merge more fixes from Andrew Morton:
"Three fixes"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
include/linux/property.h: fix typo/compile error
ocfs2: fix deadlock on mmapped page in ocfs2_write_begin_nolock()
mm: workingset: fix crash in shadow node shrinker caused by replace_page_cache_page()
This fixes commit d76eebfa17 ("include/linux/property.h: fix build
issues with gcc-4.4.4").
With that commit we get the following compile error when using the
PROPERTY_ENTRY_INTEGER_ARRAY macro.
include/linux/property.h:201:39: error: `u32_data' undeclared (first
use in this function)
PROPERTY_ENTRY_INTEGER_ARRAY(_name_, u32, _val_)
^
include/linux/property.h:193:17: note: in definition of macro
`PROPERTY_ENTRY_INTEGER_ARRAY'
{ .pointer = { _type_##_data = _val_ } }, \
^
This needs a '.' to reference the union member. It seems this was just
overlooked here since it is done correctly in similar constructs in
other parts of the original commit.
This fix is in preparation of upcoming commits that will use this macro.
Fixes: commit d76eebfa17 ("include/linux/property.h: fix build issues with gcc-4.4.4")
Link: http://lkml.kernel.org/r/2de3b929290d88a723ed829a3e3cbd02044714df.1475114627.git.johnyoun@synopsys.com
Signed-off-by: John Youn <johnyoun@synopsys.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The testcase "mmaptruncate" of ocfs2-test deadlocks occasionally.
In this testcase, we create a 2*CLUSTER_SIZE file and mmap() on it;
there are 2 process repeatedly performing the following operations
respectively: one is doing memset(mmaped_addr + 2*CLUSTER_SIZE - 1, 'a',
1), while the another is playing ftruncate(fd, 2*CLUSTER_SIZE) and then
ftruncate(fd, CLUSTER_SIZE) again and again.
This is the backtrace when the deadlock happens:
__wait_on_bit_lock+0x50/0xa0
__lock_page+0xb7/0xc0
ocfs2_write_begin_nolock+0x163f/0x1790 [ocfs2]
ocfs2_page_mkwrite+0x1c7/0x2a0 [ocfs2]
do_page_mkwrite+0x66/0xc0
handle_mm_fault+0x685/0x1350
__do_page_fault+0x1d8/0x4d0
trace_do_page_fault+0x37/0xf0
do_async_page_fault+0x19/0x70
async_page_fault+0x28/0x30
In ocfs2_write_begin_nolock(), we first grab the pages and then allocate
disk space for this write; ocfs2_try_to_free_truncate_log() will be
called if -ENOSPC is returned; if we're lucky to get enough clusters,
which is usually the case, we start over again.
But in ocfs2_free_write_ctxt() the target page isn't unlocked, so we
will deadlock when trying to grab the target page again.
Also, -ENOMEM might be returned in ocfs2_grab_pages_for_write().
Another deadlock will happen in __do_page_mkwrite() if
ocfs2_page_mkwrite() returns non-VM_FAULT_LOCKED, and along with a
locked target page.
These two errors fail on the same path, so fix them by unlocking the
target page manually before ocfs2_free_write_ctxt().
Jan Kara helps me clear out the JBD2 part, and suggest the hint for root
cause.
Changes since v1:
1. Also put ENOMEM error case into consideration.
Link: http://lkml.kernel.org/r/1474173902-32075-1-git-send-email-zren@suse.com
Signed-off-by: Eric Ren <zren@suse.com>
Reviewed-by: He Gang <ghe@suse.com>
Acked-by: Joseph Qi <joseph.qi@huawei.com>
Cc: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Antonio reports the following crash when using fuse under memory pressure:
kernel BUG at /build/linux-a2WvEb/linux-4.4.0/mm/workingset.c:346!
invalid opcode: 0000 [#1] SMP
Modules linked in: all of them
CPU: 2 PID: 63 Comm: kswapd0 Not tainted 4.4.0-36-generic #55-Ubuntu
Hardware name: System manufacturer System Product Name/P8H67-M PRO, BIOS 3904 04/27/2013
task: ffff88040cae6040 ti: ffff880407488000 task.ti: ffff880407488000
RIP: shadow_lru_isolate+0x181/0x190
Call Trace:
__list_lru_walk_one.isra.3+0x8f/0x130
list_lru_walk_one+0x23/0x30
scan_shadow_nodes+0x34/0x50
shrink_slab.part.40+0x1ed/0x3d0
shrink_zone+0x2ca/0x2e0
kswapd+0x51e/0x990
kthread+0xd8/0xf0
ret_from_fork+0x3f/0x70
which corresponds to the following sanity check in the shadow node
tracking:
BUG_ON(node->count & RADIX_TREE_COUNT_MASK);
The workingset code tracks radix tree nodes that exclusively contain
shadow entries of evicted pages in them, and this (somewhat obscure)
line checks whether there are real pages left that would interfere with
reclaim of the radix tree node under memory pressure.
While discussing ways how fuse might sneak pages into the radix tree
past the workingset code, Miklos pointed to replace_page_cache_page(),
and indeed there is a problem there: it properly accounts for the old
page being removed - __delete_from_page_cache() does that - but then
does a raw raw radix_tree_insert(), not accounting for the replacement
page. Eventually the page count bits in node->count underflow while
leaving the node incorrectly linked to the shadow node LRU.
To address this, make sure replace_page_cache_page() uses the tracked
page insertion code, page_cache_tree_insert(). This fixes the page
accounting and makes sure page-containing nodes are properly unlinked
from the shadow node LRU again.
Also, make the sanity checks a bit less obscure by using the helpers for
checking the number of pages and shadows in a radix tree node.
Fixes: 449dd6984d ("mm: keep page cache radix tree nodes in check")
Link: http://lkml.kernel.org/r/20160919155822.29498-1-hannes@cmpxchg.org
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Antonio SJ Musumeci <trapexit@spawn.link>
Debugged-by: Miklos Szeredi <miklos@szeredi.hu>
Cc: <stable@vger.kernel.org> [3.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This warning:
WARNING: CPU: 0 PID: 3331 at arch/x86/entry/common.c:45 enter_from_user_mode+0x32/0x50
CPU: 0 PID: 3331 Comm: ldt_gdt_64 Not tainted 4.8.0-rc7+ #13
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
warn_slowpath_null+0x1d/0x20
enter_from_user_mode+0x32/0x50
error_entry+0x6d/0xc0
? general_protection+0x12/0x30
? native_load_gs_index+0xd/0x20
? do_set_thread_area+0x19c/0x1f0
SyS_set_thread_area+0x24/0x30
do_int80_syscall_32+0x7c/0x220
entry_INT80_compat+0x38/0x50
... can be reproduced by running the GS testcase of the ldt_gdt test unit in
the x86 selftests.
do_int80_syscall_32() will call enter_form_user_mode() to convert context
tracking state from user state to kernel state. The load_gs_index() call
can fail with user gsbase, gsbase will be fixed up and proceed if this
happen.
However, enter_from_user_mode() will be called again in the fixed up path
though it is context tracking kernel state currently.
This patch fixes it by just fixing up gsbase and telling lockdep that IRQs
are off once load_gs_index() failed with user gsbase.
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1475197266-3440-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When sctp dumps all the ep->assocs, it needs to lock_sock first,
but now it locks sock in rcu_read_lock, and lock_sock may sleep,
which would break rcu_read_lock.
This patch is to get and hold one sock when traversing the list.
After that and get out of rcu_read_lock, lock and dump it. Then
it will traverse the list again to get the next one until all
sctp socks are dumped.
For sctp_diag_dump_one, it fixes this issue by holding asoc and
moving cb() out of rcu_read_lock in sctp_transport_lookup_process.
Fixes: 8f840e47f1 ("sctp: add the sctp_diag.c file")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Xin Long says:
====================
sctp: a bunch of fixes for prsctp polices
This patchset is to fix 2 issues for prsctp polices:
1. patch 1 and 2 fix "netperf-Throughput_Mbps -37.2% regression" issue
when overloading the CPU.
2. patch 3 fix "prsctp polices should check both sides' prsctp_capable,
instead of only local side".
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Now before using prsctp polices, sctp uses asoc->prsctp_enable to
check if prsctp is enabled. However asoc->prsctp_enable is set only
means local host support prsctp, sctp should not abandon packet if
peer host doesn't enable prsctp.
So this patch is to use asoc->peer.prsctp_capable to check if prsctp
is enabled on both side, instead of asoc->prsctp_enable, as asoc's
peer.prsctp_capable is set only when local and peer both enable prsctp.
Fixes: a6c2f79287 ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now sctp uses chunk->prsctp_param to save the prsctp param for all the
prsctp polices, we didn't need to introduce prsctp_param to sctp_chunk.
We can just use chunk->sinfo.sinfo_timetolive for RTX and BUF polices,
and reuse msg->expires_at for TTL policy, as the prsctp polices and old
expires policy are mutual exclusive.
This patch is to remove prsctp_param from sctp_chunk, and reuse msg's
expires_at for TTL and chunk's sinfo.sinfo_timetolive for RTX and BUF
polices.
Note that sctp can't use chunk's sinfo.sinfo_timetolive for TTL policy,
as it needs a u64 variables to save the expires_at time.
This one also fixes the "netperf-Throughput_Mbps -37.2% regression"
issue.
Fixes: a6c2f79287 ("sctp: implement prsctp TTL policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Emese Revfy
Linus Torvalds
Srinivas Ramana
Paul Burton
John Youn
Eric Ren
Johannes Weiner
Javi Merino
Wanpeng Li
Andy Lutomirski
Segher Boessenkool
Xin Long
David S. Miller