While __atomic_add_unless() was originally intended as a building-block
for atomic_add_unless(), it's now used in a number of places around the
kernel. It's the only common atomic operation named __atomic*(), rather
than atomic_*(), and for consistency it would be better named
atomic_fetch_add_unless().
This lack of consistency is slightly confusing, and gets in the way of
scripting atomics. Given that, let's clean things up and promote it to
an official part of the atomics API, in the form of
atomic_fetch_add_unless().
This patch converts definitions and invocations over to the new name,
including the instrumented version, using the following script:
----
git grep -w __atomic_add_unless | while read line; do
sed -i '{s/\<__atomic_add_unless\>/atomic_fetch_add_unless/}' "${line%%:*}";
done
git grep -w __arch_atomic_add_unless | while read line; do
sed -i '{s/\<__arch_atomic_add_unless\>/arch_atomic_fetch_add_unless/}' "${line%%:*}";
done
----
Note that we do not have atomic{64,_long}_fetch_add_unless(), which will
be introduced by later patches.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Palmer Dabbelt <palmer@sifive.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-2-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Provide a command line and a sysfs knob to control SMT.
The command line options are:
'nosmt': Enumerate secondary threads, but do not online them
'nosmt=force': Ignore secondary threads completely during enumeration
via MP table and ACPI/MADT.
The sysfs control file has the following states (read/write):
'on': SMT is enabled. Secondary threads can be freely onlined
'off': SMT is disabled. Secondary threads, even if enumerated
cannot be onlined
'forceoff': SMT is permanentely disabled. Writes to the control
file are rejected.
'notsupported': SMT is not supported by the CPU
The command line option 'nosmt' sets the sysfs control to 'off'. This
can be changed to 'on' to reenable SMT during runtime.
The command line option 'nosmt=force' sets the sysfs control to
'forceoff'. This cannot be changed during runtime.
When SMT is 'on' and the control file is changed to 'off' then all online
secondary threads are offlined and attempts to online a secondary thread
later on are rejected.
When SMT is 'off' and the control file is changed to 'on' then secondary
threads can be onlined again. The 'off' -> 'on' transition does not
automatically online the secondary threads.
When the control file is set to 'forceoff', the behaviour is the same as
setting it to 'off', but the operation is irreversible and later writes to
the control file are rejected.
When the control status is 'notsupported' then writes to the control file
are rejected.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Split out the inner workings of do_cpu_down() to allow reuse of that
function for the upcoming SMT disabling mechanism.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
The asymmetry caused a warning to trigger if the bootup was stopped in state
CPUHP_AP_ONLINE_IDLE. The warning no longer triggers as kthread_park() can
now be invoked on already or still parked threads. But there is still no
reason to have this be asymmetric.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
The static key sched_smt_present is only updated at boot time when SMT
siblings have been detected. Booting with maxcpus=1 and bringing the
siblings online after boot rebuilds the scheduling domains correctly but
does not update the static key, so the SMT code is not enabled.
Let the key be updated in the scheduler CPU hotplug code to fix this.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Pull networking fixes from David Miller:
1) Fix crash on bpf_prog_load() errors, from Daniel Borkmann.
2) Fix ATM VCC memory accounting, from David Woodhouse.
3) fib6_info objects need RCU freeing, from Eric Dumazet.
4) Fix SO_BINDTODEVICE handling for TCP sockets, from David Ahern.
5) Fix clobbered error code in enic_open() failure path, from
Govindarajulu Varadarajan.
6) Propagate dev_get_valid_name() error returns properly, from Li
RongQing.
7) Fix suspend/resume in davinci_emac driver, from Bartosz Golaszewski.
8) Various act_ife fixes (recursive locking, IDR leaks, etc.) from
Davide Caratti.
9) Fix buggy checksum handling in sungem driver, from Eric Dumazet.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (40 commits)
ip: limit use of gso_size to udp
stmmac: fix DMA channel hang in half-duplex mode
net: stmmac: socfpga: add additional ocp reset line for Stratix10
net: sungem: fix rx checksum support
bpfilter: ignore binary files
bpfilter: fix build error
net/usb/drivers: Remove useless hrtimer_active check
net/sched: act_ife: preserve the action control in case of error
net/sched: act_ife: fix recursive lock and idr leak
net: ethernet: fix suspend/resume in davinci_emac
net: propagate dev_get_valid_name return code
enic: do not overwrite error code
net/tcp: Fix socket lookups with SO_BINDTODEVICE
ptp: replace getnstimeofday64() with ktime_get_real_ts64()
net/ipv6: respect rcu grace period before freeing fib6_info
net: net_failover: fix typo in net_failover_slave_register()
ipvlan: use ETH_MAX_MTU as max mtu
net: hamradio: use eth_broadcast_addr
enic: initialize enic->rfs_h.lock in enic_probe
MAINTAINERS: Add Sam as the maintainer for NCSI
...
Pull dma-mapping rename from Christoph Hellwig:
"Move all the dma-mapping code to kernel/dma and lose their dma-*
prefixes"
* tag 'dma-rename-4.18' of git://git.infradead.org/users/hch/dma-mapping:
dma-mapping: move all DMA mapping code to kernel/dma
dma-mapping: use obj-y instead of lib-y for generic dma ops
The AUDIT_FILTER_TYPE name is vague and misleading due to not describing
where or when the filter is applied and obsolete due to its available
filter fields having been expanded.
Userspace has already renamed it from AUDIT_FILTER_TYPE to
AUDIT_FILTER_EXCLUDE without checking if it already exists. The
userspace maintainer assures that as long as it is set to the same value
it will not be a problem since the userspace code does not treat
compiler warnings as errors. If this policy changes then checks if it
already exists can be added at the same time.
See: https://github.com/linux-audit/audit-kernel/issues/89
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The audit_filter_rules() function in auditsc.c used the in_[e]group_p()
functions to check GID/EGID match, but these functions use the current
task's credentials, while the comparison should use the credentials of
the task given to audit_filter_rules() as a parameter (tsk).
Note that we can use group_search(cred->group_info, ...) as a
replacement for both in_group_p and in_egroup_p as these functions only
compare the parameter to cred->fsgid/egid and then call group_search.
In fact, the usage of in_group_p was even more incorrect: it compares to
cred->fsgid (which is usually equal to cred->egid) and not cred->gid.
GitHub issue:
https://github.com/linux-audit/audit-kernel/issues/82
Fixes: 37eebe39c9 ("audit: improve GID/EGID comparation logic")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch removes the restriction of the AUDIT_EXE field to only
SYSCALL filter and teaches audit_filter to recognize this field.
This makes it possible to write rule lists such as:
auditctl -a exit,always [some general rule]
# Filter out events with executable name /bin/exe1 or /bin/exe2:
auditctl -a exclude,always -F exe=/bin/exe1
auditctl -a exclude,always -F exe=/bin/exe2
See: https://github.com/linux-audit/audit-kernel/issues/54
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
Reviewed-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Livepatch modules are special in that we preserve their entire symbol
tables in order to be able to apply relocations after module load. The
unwanted side effect of this is that undefined (SHN_UNDEF) symbols of
livepatch modules are accessible via the kallsyms api and this can
confuse symbol resolution in livepatch (klp_find_object_symbol()) and
cause subtle bugs in livepatch.
Have the module kallsyms api skip over SHN_UNDEF symbols. These symbols
are usually not available for normal modules anyway as we cut down their
symbol tables to just the core (non-undefined) symbols, so this should
really just affect livepatch modules. Note that this patch doesn't
affect the display of undefined symbols in /proc/kallsyms.
Reported-by: Josh Poimboeuf <jpoimboe@redhat.com>
Tested-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf 2018-06-16
The following pull-request contains BPF updates for your *net* tree.
The main changes are:
1) Fix a panic in devmap handling in generic XDP where return type
of __devmap_lookup_elem() got changed recently but generic XDP
code missed the related update, from Toshiaki.
2) Fix a freeze when BPF progs are loaded that include BPF to BPF
calls when JIT is enabled where we would later bail out via error
path w/o dropping kallsyms, and another one to silence syzkaller
splats from locking prog read-only, from Daniel.
3) Fix a bug in test_offloads.py BPF selftest which must not assume
that the underlying system have no BPF progs loaded prior to test,
and one in bpftool to fix accuracy of program load time, from Jakub.
4) Fix a bug in bpftool's probe for availability of the bpf(2)
BPF_TASK_FD_QUERY subcommand, from Yonghong.
5) Fix a regression in AF_XDP's XDP_SKB receive path where queue
id check got erroneously removed, from Björn.
6) Fix missing state cleanup in BPF's xfrm tunnel test, from William.
7) Check tunnel type more accurately in BPF's tunnel collect metadata
kselftest, from Jian.
8) Fix missing Kconfig fragments for BPF kselftests, from Anders.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
Pull documentation fixes from Mauro Carvalho Chehab:
"This solves a series of broken links for files under Documentation,
and improves a script meant to detect such broken links (see
scripts/documentation-file-ref-check).
The changes on this series are:
- can.rst: fix a footnote reference;
- crypto_engine.rst: Fix two parsing warnings;
- Fix a lot of broken references to Documentation/*;
- improve the scripts/documentation-file-ref-check script, in order
to help detecting/fixing broken references, preventing
false-positives.
After this patch series, only 33 broken references to doc files are
detected by scripts/documentation-file-ref-check"
* tag 'docs-broken-links' of git://linuxtv.org/mchehab/experimental: (26 commits)
fix a series of Documentation/ broken file name references
Documentation: rstFlatTable.py: fix a broken reference
ABI: sysfs-devices-system-cpu: remove a broken reference
devicetree: fix a series of wrong file references
devicetree: fix name of pinctrl-bindings.txt
devicetree: fix some bindings file names
MAINTAINERS: fix location of DT npcm files
MAINTAINERS: fix location of some display DT bindings
kernel-parameters.txt: fix pointers to sound parameters
bindings: nvmem/zii: Fix location of nvmem.txt
docs: Fix more broken references
scripts/documentation-file-ref-check: check tools/*/Documentation
scripts/documentation-file-ref-check: get rid of false-positives
scripts/documentation-file-ref-check: hint: dash or underline
scripts/documentation-file-ref-check: add a fix logic for DT
scripts/documentation-file-ref-check: accept more wildcards at filenames
scripts/documentation-file-ref-check: fix help message
media: max2175: fix location of driver's companion documentation
media: v4l: fix broken video4linux docs locations
media: dvb: point to the location of the old README.dvb-usb file
...
Pull fsnotify updates from Jan Kara:
"fsnotify cleanups unifying handling of different watch types.
This is the shortened fsnotify series from Amir with the last five
patches pulled out. Amir has modified those patches to not change
struct inode but obviously it's too late for those to go into this
merge window"
* tag 'fsnotify_for_v4.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
fsnotify: add fsnotify_add_inode_mark() wrappers
fanotify: generalize fanotify_should_send_event()
fsnotify: generalize send_to_group()
fsnotify: generalize iteration of marks by object type
fsnotify: introduce marks iteration helpers
fsnotify: remove redundant arguments to handle_event()
fsnotify: use type id to identify connector object type
Pull networking fixes from David Miller:
1) Various netfilter fixlets from Pablo and the netfilter team.
2) Fix regression in IPVS caused by lack of PMTU exceptions on local
routes in ipv6, from Julian Anastasov.
3) Check pskb_trim_rcsum for failure in DSA, from Zhouyang Jia.
4) Don't crash on poll in TLS, from Daniel Borkmann.
5) Revert SO_REUSE{ADDR,PORT} change, it regresses various things
including Avahi mDNS. From Bart Van Assche.
6) Missing of_node_put in qcom/emac driver, from Yue Haibing.
7) We lack checking of the TCP checking in one special case during SYN
receive, from Frank van der Linden.
8) Fix module init error paths of mac80211 hwsim, from Johannes Berg.
9) Handle 802.1ad properly in stmmac driver, from Elad Nachman.
10) Must grab HW caps before doing quirk checks in stmmac driver, from
Jose Abreu.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (81 commits)
net: stmmac: Run HWIF Quirks after getting HW caps
neighbour: skip NTF_EXT_LEARNED entries during forced gc
net: cxgb3: add error handling for sysfs_create_group
tls: fix waitall behavior in tls_sw_recvmsg
tls: fix use-after-free in tls_push_record
l2tp: filter out non-PPP sessions in pppol2tp_tunnel_ioctl()
l2tp: reject creation of non-PPP sessions on L2TPv2 tunnels
mlxsw: spectrum_switchdev: Fix port_vlan refcounting
mlxsw: spectrum_router: Align with new route replace logic
mlxsw: spectrum_router: Allow appending to dev-only routes
ipv6: Only emit append events for appended routes
stmmac: added support for 802.1ad vlan stripping
cfg80211: fix rcu in cfg80211_unregister_wdev
mac80211: Move up init of TXQs
mac80211_hwsim: fix module init error paths
cfg80211: initialize sinfo in cfg80211_get_station
nl80211: fix some kernel doc tag mistakes
hv_netvsc: Fix the variable sizes in ipsecv2 and rsc offload
rds: avoid unenecessary cong_update in loop transport
l2tp: clean up stale tunnel or session in pppol2tp_connect's error path
...
Pull module updates from Jessica Yu:
"Minor code cleanup and also allow sig_enforce param to be shown in
sysfs with CONFIG_MODULE_SIG_FORCE"
* tag 'modules-for-v4.18' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
module: Allow to always show the status of modsign
module: Do not access sig_enforce directly
Commit 67f29e07e1 ("bpf: devmap introduce dev_map_enqueue") changed
the return value type of __devmap_lookup_elem() from struct net_device *
to struct bpf_dtab_netdev * but forgot to modify generic XDP code
accordingly.
Thus generic XDP incorrectly used struct bpf_dtab_netdev where struct
net_device is expected, then skb->dev was set to invalid value.
v2:
- Fix compiler warning without CONFIG_BPF_SYSCALL.
Fixes: 67f29e07e1 ("bpf: devmap introduce dev_map_enqueue")
Signed-off-by: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Acked-by: Yonghong Song <yhs@fb.com>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
We currently lock any JITed image as read-only via bpf_jit_binary_lock_ro()
as well as the BPF image as read-only through bpf_prog_lock_ro(). In
the case any of these would fail we throw a WARN_ON_ONCE() in order to
yell loudly to the log. Perhaps, to some extend, this may be comparable
to an allocation where __GFP_NOWARN is explicitly not set.
Added via 65869a47f3 ("bpf: improve read-only handling"), this behavior
is slightly different compared to any of the other in-kernel set_memory_ro()
users who do not check the return code of set_memory_ro() and friends /at
all/ (e.g. in the case of module_enable_ro() / module_disable_ro()). Given
in BPF this is mandatory hardening step, we want to know whether there
are any issues that would leave both BPF data writable. So it happens
that syzkaller enabled fault injection and it triggered memory allocation
failure deep inside x86's change_page_attr_set_clr() which was triggered
from set_memory_ro().
Now, there are two options: i) leaving everything as is, and ii) reworking
the image locking code in order to have a final checkpoint out of the
central bpf_prog_select_runtime() which probes whether any of the calls
during prog setup weren't successful, and then bailing out with an error.
Option ii) is a better approach since this additional paranoia avoids
altogether leaving any potential W+X pages from BPF side in the system.
Therefore, lets be strict about it, and reject programs in such unlikely
occasion. While testing I noticed also that one bpf_prog_lock_ro()
call was missing on the outer dummy prog in case of calls, e.g. in the
destructor we call bpf_prog_free_deferred() on the main prog where we
try to bpf_prog_unlock_free() the program, and since we go via
bpf_prog_select_runtime() do that as well.
Reported-by: syzbot+3b889862e65a98317058@syzkaller.appspotmail.com
Reported-by: syzbot+9e762b52dd17e616a7a5@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
While testing I found that when hitting error path in bpf_prog_load()
where we jump to free_used_maps and prog contained BPF to BPF calls
that were JITed earlier, then we never clean up the bpf_prog_kallsyms_add()
done under jit_subprogs(). Add proper API to make BPF kallsyms deletion
more clear and fix that.
Fixes: 1c2a088a66 ("bpf: x64: add JIT support for multi-function programs")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Merge more updates from Andrew Morton:
- MM remainders
- various misc things
- kcov updates
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (27 commits)
lib/test_printf.c: call wait_for_random_bytes() before plain %p tests
hexagon: drop the unused variable zero_page_mask
hexagon: fix printk format warning in setup.c
mm: fix oom_kill event handling
treewide: use PHYS_ADDR_MAX to avoid type casting ULLONG_MAX
mm: use octal not symbolic permissions
ipc: use new return type vm_fault_t
sysvipc/sem: mitigate semnum index against spectre v1
fault-injection: reorder config entries
arm: port KCOV to arm
sched/core / kcov: avoid kcov_area during task switch
kcov: prefault the kcov_area
kcov: ensure irq code sees a valid area
kernel/relay.c: change return type to vm_fault_t
exofs: avoid VLA in structures
coredump: fix spam with zero VMA process
fat: use fat_fs_error() instead of BUG_ON() in __fat_get_block()
proc: skip branch in /proc/*/* lookup
mremap: remove LATENCY_LIMIT from mremap to reduce the number of TLB shootdowns
mm/memblock: add missing include <linux/bootmem.h>
...
During a context switch, we first switch_mm() to the next task's mm,
then switch_to() that new task. This means that vmalloc'd regions which
had previously been faulted in can transiently disappear in the context
of the prev task.
Functions instrumented by KCOV may try to access a vmalloc'd kcov_area
during this window, and as the fault handling code is instrumented, this
results in a recursive fault.
We must avoid accessing any kcov_area during this window. We can do so
with a new flag in kcov_mode, set prior to switching the mm, and cleared
once the new task is live. Since task_struct::kcov_mode isn't always a
specific enum kcov_mode value, this is made an unsigned int.
The manipulation is hidden behind kcov_{prepare,finish}_switch() helpers,
which are empty for !CONFIG_KCOV kernels.
The code uses macros because I can't use static inline functions without a
circular include dependency between <linux/sched.h> and <linux/kcov.h>,
since the definition of task_struct uses things defined in <linux/kcov.h>
Link: http://lkml.kernel.org/r/20180504135535.53744-4-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On many architectures the vmalloc area is lazily faulted in upon first
access. This is problematic for KCOV, as __sanitizer_cov_trace_pc
accesses the (vmalloc'd) kcov_area, and fault handling code may be
instrumented. If an access to kcov_area faults, this will result in
mutual recursion through the fault handling code and
__sanitizer_cov_trace_pc(), eventually leading to stack corruption
and/or overflow.
We can avoid this by faulting in the kcov_area before
__sanitizer_cov_trace_pc() is permitted to access it. Once it has been
faulted in, it will remain present in the process page tables, and will
not fault again.
[akpm@linux-foundation.org: code cleanup]
[akpm@linux-foundation.org: add comment explaining kcov_fault_in_area()]
[akpm@linux-foundation.org: fancier code comment from Mark]
Link: http://lkml.kernel.org/r/20180504135535.53744-3-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "kcov: fix unexpected faults".
These patches fix a few issues where KCOV code could trigger recursive
faults, discovered while debugging a patch enabling KCOV for arch/arm:
* On CONFIG_PREEMPT kernels, there's a small race window where
__sanitizer_cov_trace_pc() can see a bogus kcov_area.
* Lazy faulting of the vmalloc area can cause mutual recursion between
fault handling code and __sanitizer_cov_trace_pc().
* During the context switch, switching the mm can cause the kcov_area to
be transiently unmapped.
These are prerequisites for enabling KCOV on arm, but the issues
themsevles are generic -- we just happen to avoid them by chance rather
than design on x86-64 and arm64.
This patch (of 3):
For kernels built with CONFIG_PREEMPT, some C code may execute before or
after the interrupt handler, while the hardirq count is zero. In these
cases, in_task() can return true.
A task can be interrupted in the middle of a KCOV_DISABLE ioctl while it
resets the task's kcov data via kcov_task_init(). Instrumented code
executed during this period will call __sanitizer_cov_trace_pc(), and as
in_task() returns true, will inspect t->kcov_mode before trying to write
to t->kcov_area.
In kcov_init_task() we update t->kcov_{mode,area,size} with plain stores,
which may be re-ordered, torn, etc. Thus __sanitizer_cov_trace_pc() may
see bogus values for any of these fields, and may attempt to write to
memory which is not mapped.
Let's avoid this by using WRITE_ONCE() to set t->kcov_mode, with a
barrier() to ensure this is ordered before we clear t->kov_{area,size}.
This ensures that any code execute while kcov_init_task() is preempted
will either see valid values for t->kcov_{area,size}, or will see that
t->kcov_mode is KCOV_MODE_DISABLED, and bail out without touching
t->kcov_area.
Link: http://lkml.kernel.org/r/20180504135535.53744-2-mark.rutland@arm.com
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As a theoretical problem, dup_mmap() of an mm_struct with 60000+ vmas
can loop while potentially allocating memory, with mm->mmap_sem held for
write by current thread. This is bad if current thread was selected as
an OOM victim, for current thread will continue allocations using memory
reserves while OOM reaper is unable to reclaim memory.
As an actually observable problem, it is not difficult to make OOM
reaper unable to reclaim memory if the OOM victim is blocked at
i_mmap_lock_write() in this loop. Unfortunately, since nobody can
explain whether it is safe to use killable wait there, let's check for
SIGKILL before trying to allocate memory. Even without an OOM event,
there is no point with continuing the loop from the beginning if current
thread is killed.
I tested with debug printk(). This patch should be safe because we
already fail if security_vm_enough_memory_mm() or
kmem_cache_alloc(GFP_KERNEL) fails and exit_mmap() handles it.
***** Aborting dup_mmap() due to SIGKILL *****
***** Aborting dup_mmap() due to SIGKILL *****
***** Aborting dup_mmap() due to SIGKILL *****
***** Aborting dup_mmap() due to SIGKILL *****
***** Aborting exit_mmap() due to NULL mmap *****
[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/201804071938.CDE04681.SOFVQJFtMHOOLF@I-love.SAKURA.ne.jp
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Without yielding while loading kimage segments, a large initrd will
block all other work on the CPU performing the load until it is
completed. For example loading an initrd of 200MB on a low power single
core system will lock up the system for a few seconds.
To increase system responsiveness to other tasks at that time, call
cond_resched() in both the crash kernel and normal kernel segment
loading loops.
I did run into a practical problem. Hardware watchdogs on embedded
systems can have short timers on the order of seconds. If the system is
locked up for a few seconds with only a single core available, the
watchdog may not be pet in a timely fashion. If this happens, the
hardware watchdog will fire and reset the system.
This really only becomes a problem when you are working with a single
core, a decently sized initrd, and have a constrained hardware watchdog.
Link: http://lkml.kernel.org/r/1528738546-3328-1-git-send-email-jmf@amazon.com
Signed-off-by: Jarrett Farnitano <jmf@amazon.com>
Reviewed-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Prior to commit 2a61f4747e ("stack-protector: test compiler capability
in Kconfig and drop AUTO mode"), the stack protector was configured by
the choice of NONE, REGULAR, STRONG, AUTO.
tiny.config needed to explicitly set NONE because the default value of
choice, AUTO, did not produce the tiniest kernel.
Now that there are only two boolean symbols, STACKPROTECTOR and
STACKPROTECTOR_STRONG, they are naturally disabled by "make
allnoconfig", which "make tinyconfig" is based on. Remove unnecessary
lines from the tiny.config fragment file.
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently the code is split over various files with dma- prefixes in the
lib/ and drives/base directories, and the number of files keeps growing.
Move them into a single directory to keep the code together and remove
the file name prefixes. To match the irq infrastructure this directory
is placed under the kernel/ directory.
Signed-off-by: Christoph Hellwig <hch@lst.de>
The changes to automatically test for working stack protector compiler
support in the Kconfig files removed the special STACKPROTECTOR_AUTO
option that picked the strongest stack protector that the compiler
supported.
That was all a nice cleanup - it makes no sense to have the AUTO case
now that the Kconfig phase can just determine the compiler support
directly.
HOWEVER.
It also meant that doing "make oldconfig" would now _disable_ the strong
stackprotector if you had AUTO enabled, because in a legacy config file,
the sane stack protector configuration would look like
CONFIG_HAVE_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_NONE is not set
# CONFIG_CC_STACKPROTECTOR_REGULAR is not set
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_CC_STACKPROTECTOR_AUTO=y
and when you ran this through "make oldconfig" with the Kbuild changes,
it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had
been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just
CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version
used to be disabled (because it was really enabled by AUTO), and would
disable it in the new config, resulting in:
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
CONFIG_CC_STACKPROTECTOR=y
# CONFIG_CC_STACKPROTECTOR_STRONG is not set
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
That's dangerously subtle - people could suddenly find themselves with
the weaker stack protector setup without even realizing.
The solution here is to just rename not just the old RECULAR stack
protector option, but also the strong one. This does that by just
removing the CC_ prefix entirely for the user choices, because it really
is not about the compiler support (the compiler support now instead
automatially impacts _visibility_ of the options to users).
This results in "make oldconfig" actually asking the user for their
choice, so that we don't have any silent subtle security model changes.
The end result would generally look like this:
CONFIG_HAVE_CC_STACKPROTECTOR=y
CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
CONFIG_STACKPROTECTOR=y
CONFIG_STACKPROTECTOR_STRONG=y
CONFIG_CC_HAS_SANE_STACKPROTECTOR=y
where the "CC_" versions really are about internal compiler
infrastructure, not the user selections.
Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull more Kbuild updates from Masahiro Yamada:
- fix some bugs introduced by the recent Kconfig syntax extension
- add some symbols about compiler information in Kconfig, such as
CC_IS_GCC, CC_IS_CLANG, GCC_VERSION, etc.
- test compiler capability for the stack protector in Kconfig, and
clean-up Makefile
- test compiler capability for GCC-plugins in Kconfig, and clean-up
Makefile
- allow to enable GCC-plugins for COMPILE_TEST
- test compiler capability for KCOV in Kconfig and correct dependency
- remove auto-detect mode of the GCOV format, which is now more nicely
handled in Kconfig
- test compiler capability for mprofile-kernel on PowerPC, and clean-up
Makefile
- misc cleanups
* tag 'kbuild-v4.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
linux/linkage.h: replace VMLINUX_SYMBOL_STR() with __stringify()
kconfig: fix localmodconfig
sh: remove no-op macro VMLINUX_SYMBOL()
powerpc/kbuild: move -mprofile-kernel check to Kconfig
Documentation: kconfig: add recommended way to describe compiler support
gcc-plugins: disable GCC_PLUGIN_STRUCTLEAK_BYREF_ALL for COMPILE_TEST
gcc-plugins: allow to enable GCC_PLUGINS for COMPILE_TEST
gcc-plugins: test plugin support in Kconfig and clean up Makefile
gcc-plugins: move GCC version check for PowerPC to Kconfig
kcov: test compiler capability in Kconfig and correct dependency
gcov: remove CONFIG_GCOV_FORMAT_AUTODETECT
arm64: move GCC version check for ARCH_SUPPORTS_INT128 to Kconfig
kconfig: add CC_IS_CLANG and CLANG_VERSION
kconfig: add CC_IS_GCC and GCC_VERSION
stack-protector: test compiler capability in Kconfig and drop AUTO mode
kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE
