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Paul reported rcutorture occasionally hitting a NULL deref:
sched_ttwu_pending()
ttwu_do_wakeup()
check_preempt_curr() := check_preempt_wakeup()
find_matching_se()
is_same_group()
if (se->cfs_rq == pse->cfs_rq) <-- *BOOM*
Debugging showed that this only appears to happen when we take the new
code-path from commit:
2ebb17717550 ("sched/core: Offload wakee task activation if it the wakee is descheduling")
and only when @cpu == smp_processor_id(). Something which should not
be possible, because p->on_cpu can only be true for remote tasks.
Similarly, without the new code-path from commit:
c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu")
this would've unconditionally hit:
smp_cond_load_acquire(&p->on_cpu, !VAL);
and if: 'cpu == smp_processor_id() && p->on_cpu' is possible, this
would result in an instant live-lock (with IRQs disabled), something
that hasn't been reported.
The NULL deref can be explained however if the task_cpu(p) load at the
beginning of try_to_wake_up() returns an old value, and this old value
happens to be smp_processor_id(). Further assume that the p->on_cpu
load accurately returns 1, it really is still running, just not here.
Then, when we enqueue the task locally, we can crash in exactly the
observed manner because p->se.cfs_rq != rq->cfs_rq, because p's cfs_rq
is from the wrong CPU, therefore we'll iterate into the non-existant
parents and NULL deref.
The closest semi-plausible scenario I've managed to contrive is
somewhat elaborate (then again, actual reproduction takes many CPU
hours of rcutorture, so it can't be anything obvious):
X->cpu = 1
rq(1)->curr = X
CPU0 CPU1 CPU2
// switch away from X
LOCK rq(1)->lock
smp_mb__after_spinlock
dequeue_task(X)
X->on_rq = 9
switch_to(Z)
X->on_cpu = 0
UNLOCK rq(1)->lock
// migrate X to cpu 0
LOCK rq(1)->lock
dequeue_task(X)
set_task_cpu(X, 0)
X->cpu = 0
UNLOCK rq(1)->lock
LOCK rq(0)->lock
enqueue_task(X)
X->on_rq = 1
UNLOCK rq(0)->lock
// switch to X
LOCK rq(0)->lock
smp_mb__after_spinlock
switch_to(X)
X->on_cpu = 1
UNLOCK rq(0)->lock
// X goes sleep
X->state = TASK_UNINTERRUPTIBLE
smp_mb(); // wake X
ttwu()
LOCK X->pi_lock
smp_mb__after_spinlock
if (p->state)
cpu = X->cpu; // =? 1
smp_rmb()
// X calls schedule()
LOCK rq(0)->lock
smp_mb__after_spinlock
dequeue_task(X)
X->on_rq = 0
if (p->on_rq)
smp_rmb();
if (p->on_cpu && ttwu_queue_wakelist(..)) [*]
smp_cond_load_acquire(&p->on_cpu, !VAL)
cpu = select_task_rq(X, X->wake_cpu, ...)
if (X->cpu != cpu)
switch_to(Y)
X->on_cpu = 0
UNLOCK rq(0)->lock
However I'm having trouble convincing myself that's actually possible
on x86_64 -- after all, every LOCK implies an smp_mb() there, so if ttwu
observes ->state != RUNNING, it must also observe ->cpu != 1.
(Most of the previous ttwu() races were found on very large PowerPC)
Nevertheless, this fully explains the observed failure case.
Fix it by ordering the task_cpu(p) load after the p->on_cpu load,
which is easy since nothing actually uses @cpu before this.
Fixes: c6e7bd7afaeb ("sched/core: Optimize ttwu() spinning on p->on_cpu")
Reported-by: Paul E. McKenney <paulmck@kernel.org>
Tested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200622125649.GC576871@hirez.programming.kicks-ass.net
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syzbot reported the following warning:
WARNING: CPU: 1 PID: 6351 at kernel/sched/deadline.c:628
enqueue_task_dl+0x22da/0x38a0 kernel/sched/deadline.c:1504
At deadline.c:628 we have:
623 static inline void setup_new_dl_entity(struct sched_dl_entity *dl_se)
624 {
625 struct dl_rq *dl_rq = dl_rq_of_se(dl_se);
626 struct rq *rq = rq_of_dl_rq(dl_rq);
627
628 WARN_ON(dl_se->dl_boosted);
629 WARN_ON(dl_time_before(rq_clock(rq), dl_se->deadline));
[...]
}
Which means that setup_new_dl_entity() has been called on a task
currently boosted. This shouldn't happen though, as setup_new_dl_entity()
is only called when the 'dynamic' deadline of the new entity
is in the past w.r.t. rq_clock and boosted tasks shouldn't verify this
condition.
Digging through the PI code I noticed that what above might in fact happen
if an RT tasks blocks on an rt_mutex hold by a DEADLINE task. In the
first branch of boosting conditions we check only if a pi_task 'dynamic'
deadline is earlier than mutex holder's and in this case we set mutex
holder to be dl_boosted. However, since RT 'dynamic' deadlines are only
initialized if such tasks get boosted at some point (or if they become
DEADLINE of course), in general RT 'dynamic' deadlines are usually equal
to 0 and this verifies the aforementioned condition.
Fix it by checking that the potential donor task is actually (even if
temporary because in turn boosted) running at DEADLINE priority before
using its 'dynamic' deadline value.
Fixes: 2d3d891d3344 ("sched/deadline: Add SCHED_DEADLINE inheritance logic")
Reported-by: syzbot+119ba87189432ead09b4@syzkaller.appspotmail.com
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Tested-by: Daniel Wagner <dwagner@suse.de>
Link: https://lkml.kernel.org/r/20181119153201.GB2119@localhost.localdomain
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syzbot reported the following warning triggered via SYSC_sched_setattr():
WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 setup_new_dl_entity /kernel/sched/deadline.c:594 [inline]
WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_dl_entity /kernel/sched/deadline.c:1370 [inline]
WARNING: CPU: 0 PID: 6973 at kernel/sched/deadline.c:593 enqueue_task_dl+0x1c17/0x2ba0 /kernel/sched/deadline.c:1441
This happens because the ->dl_boosted flag is currently not initialized by
__dl_clear_params() (unlike the other flags) and setup_new_dl_entity()
rightfully complains about it.
Initialize dl_boosted to 0.
Fixes: 2d3d891d3344 ("sched/deadline: Add SCHED_DEADLINE inheritance logic")
Reported-by: syzbot+5ac8bac25f95e8b221e7@syzkaller.appspotmail.com
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Daniel Wagner <dwagner@suse.de>
Link: https://lkml.kernel.org/r/20200617072919.818409-1-juri.lelli@redhat.com
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fix mask corruption
This function is concerned with the long-term CPU mask, not the
transitory mask the task might have while migrate disabled. Before
this patch, if a task was migrate-disabled at the time
__set_cpus_allowed_ptr() was called, and the new mask happened to be
equal to the CPU that the task was running on, then the mask update
would be lost.
Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20200617121742.cpxppyi7twxmpin7@linutronix.de
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Pull dma-mapping fixes from Christoph Hellwig:
- fix dma coherent mmap in nommu (me)
- more AMD SEV fallout (David Rientjes, me)
- fix alignment in dma_common_*_remap (Eric Auger)
* tag 'dma-mapping-5.8-4' of git://git.infradead.org/users/hch/dma-mapping:
dma-remap: align the size in dma_common_*_remap()
dma-mapping: DMA_COHERENT_POOL should select GENERIC_ALLOCATOR
dma-direct: add missing set_memory_decrypted() for coherent mapping
dma-direct: check return value when encrypting or decrypting memory
dma-direct: re-encrypt memory if dma_direct_alloc_pages() fails
dma-direct: always align allocation size in dma_direct_alloc_pages()
dma-direct: mark __dma_direct_alloc_pages static
dma-direct: re-enable mmap for !CONFIG_MMU
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git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux
Pull kgdb fixes from Daniel Thompson:
"The main change here is a fix for a number of unsafe interactions
between kdb and the console system. The fixes are specific to kdb
(pure kgdb debugging does not use the console system at all). On
systems with an NMI then kdb, if it is enabled, must get messages to
the user despite potentially running from some "difficult" calling
contexts. These fixes avoid using the console system where we have
been provided an alternative (safer) way to interact with the user
and, if using the console system in unavoidable, use oops_in_progress
for deadlock avoidance. These fixes also ensure kdb honours the
console enable flag.
Also included is a fix that wraps kgdb trap handling in an RCU read
lock to avoids triggering diagnostic warnings. This is a wide lock
scope but this is OK because kgdb is a stop-the-world debugger. When
we stop the world we put all the CPUs into holding pens and this
inhibits RCU update anyway"
* tag 'kgdb-5.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
kgdb: Avoid suspicious RCU usage warning
kdb: Switch to use safer dbg_io_ops over console APIs
kdb: Make kdb_printf() console handling more robust
kdb: Check status of console prior to invoking handlers
kdb: Re-factor kdb_printf() message write code
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix a recent regression that broke suspend-to-idle on some x86
systems, fix the intel_pstate driver to correctly let the platform
firmware control CPU performance in some cases and add __init
annotations to a couple of functions.
Specifics:
- Make sure that the _TIF_POLLING_NRFLAG is clear before entering the
last phase of suspend-to-idle to avoid wakeup issues on some x86
systems (Chen Yu, Rafael Wysocki).
- Cover one more case in which the intel_pstate driver should let the
platform firmware control the CPU frequency and refuse to load
(Srinivas Pandruvada).
- Add __init annotations to 2 functions in the power management core
(Christophe JAILLET)"
* tag 'pm-5.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpuidle: Rearrange s2idle-specific idle state entry code
PM: sleep: core: mark 2 functions as __init to save some memory
cpufreq: intel_pstate: Add one more OOB control bit
PM: s2idle: Clear _TIF_POLLING_NRFLAG before suspend to idle
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Merge misx fixes from Andrew Morton:
"31 patches.
Subsystems affected by this patch series: hotfixes, mm/pagealloc,
kexec, ocfs2, lib, mm/slab, mm/slab, mm/slub, mm/swap, mm/pagemap,
mm/vmalloc, mm/memcg, mm/gup, mm/thp, mm/vmscan, x86,
mm/memory-hotplug, MAINTAINERS"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (31 commits)
MAINTAINERS: update info for sparse
mm/memory_hotplug.c: fix false softlockup during pfn range removal
mm: remove vmalloc_exec
arm64: use PAGE_KERNEL_ROX directly in alloc_insn_page
x86/hyperv: allocate the hypercall page with only read and execute bits
mm/memory: fix IO cost for anonymous page
mm/swap: fix for "mm: workingset: age nonresident information alongside anonymous pages"
mm: workingset: age nonresident information alongside anonymous pages
doc: THP CoW fault no longer allocate THP
docs: mm/gup: minor documentation update
mm/memcontrol.c: prevent missed memory.low load tears
mm/memcontrol.c: add missed css_put()
mm: memcontrol: handle div0 crash race condition in memory.low
mm/vmalloc.c: fix a warning while make xmldocs
media: omap3isp: remove cacheflush.h
make asm-generic/cacheflush.h more standalone
mm/debug_vm_pgtable: fix build failure with powerpc 8xx
mm/memory.c: properly pte_offset_map_lock/unlock in vm_insert_pages()
mm: fix swap cache node allocation mask
slub: cure list_slab_objects() from double fix
...
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At times when I'm using kgdb I see a splat on my console about
suspicious RCU usage. I managed to come up with a case that could
reproduce this that looked like this:
WARNING: suspicious RCU usage
5.7.0-rc4+ #609 Not tainted
-----------------------------
kernel/pid.c:395 find_task_by_pid_ns() needs rcu_read_lock() protection!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
3 locks held by swapper/0/1:
#0: ffffff81b6b8e988 (&dev->mutex){....}-{3:3}, at: __device_attach+0x40/0x13c
#1: ffffffd01109e9e8 (dbg_master_lock){....}-{2:2}, at: kgdb_cpu_enter+0x20c/0x7ac
#2: ffffffd01109ea90 (dbg_slave_lock){....}-{2:2}, at: kgdb_cpu_enter+0x3ec/0x7ac
stack backtrace:
CPU: 7 PID: 1 Comm: swapper/0 Not tainted 5.7.0-rc4+ #609
Hardware name: Google Cheza (rev3+) (DT)
Call trace:
dump_backtrace+0x0/0x1b8
show_stack+0x1c/0x24
dump_stack+0xd4/0x134
lockdep_rcu_suspicious+0xf0/0x100
find_task_by_pid_ns+0x5c/0x80
getthread+0x8c/0xb0
gdb_serial_stub+0x9d4/0xd04
kgdb_cpu_enter+0x284/0x7ac
kgdb_handle_exception+0x174/0x20c
kgdb_brk_fn+0x24/0x30
call_break_hook+0x6c/0x7c
brk_handler+0x20/0x5c
do_debug_exception+0x1c8/0x22c
el1_sync_handler+0x3c/0xe4
el1_sync+0x7c/0x100
rpmh_rsc_probe+0x38/0x420
platform_drv_probe+0x94/0xb4
really_probe+0x134/0x300
driver_probe_device+0x68/0x100
__device_attach_driver+0x90/0xa8
bus_for_each_drv+0x84/0xcc
__device_attach+0xb4/0x13c
device_initial_probe+0x18/0x20
bus_probe_device+0x38/0x98
device_add+0x38c/0x420
If I understand properly we should just be able to blanket kgdb under
one big RCU read lock and the problem should go away. We'll add it to
the beast-of-a-function known as kgdb_cpu_enter().
With this I no longer get any splats and things seem to work fine.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20200602154729.v2.1.I70e0d4fd46d5ed2aaf0c98a355e8e1b7a5bb7e4e@changeid
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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In kgdb context, calling console handlers aren't safe due to locks used
in those handlers which could in turn lead to a deadlock. Although, using
oops_in_progress increases the chance to bypass locks in most console
handlers but it might not be sufficient enough in case a console uses
more locks (VT/TTY is good example).
Currently when a driver provides both polling I/O and a console then kdb
will output using the console. We can increase robustness by using the
currently active polling I/O driver (which should be lockless) instead
of the corresponding console. For several common cases (e.g. an
embedded system with a single serial port that is used both for console
output and debugger I/O) this will result in no console handler being
used.
In order to achieve this we need to reverse the order of preference to
use dbg_io_ops (uses polling I/O mode) over console APIs. So we just
store "struct console" that represents debugger I/O in dbg_io_ops and
while emitting kdb messages, skip console that matches dbg_io_ops
console in order to avoid duplicate messages. After this change,
"is_console" param becomes redundant and hence removed.
Suggested-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Link: https://lore.kernel.org/r/1591264879-25920-5-git-send-email-sumit.garg@linaro.org
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
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Merge vmalloc_exec into its only caller. Note that for !CONFIG_MMU
__vmalloc_node_range maps to __vmalloc, which directly clears the
__GFP_HIGHMEM added by the vmalloc_exec stub anyway.
Link: http://lkml.kernel.org/r/20200618064307.32739-4-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Jessica Yu <jeyu@kernel.org>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signature verification is an important security feature, to protect
system from being attacked with a kernel of unknown origin. Kexec
rebooting is a way to replace the running kernel, hence need be secured
carefully.
In the current code of handling signature verification of kexec kernel,
the logic is very twisted. It mixes signature verification, IMA
signature appraising and kexec lockdown.
If there is no KEXEC_SIG_FORCE, kexec kernel image doesn't have one of
signature, the supported crypto, and key, we don't think this is wrong,
Unless kexec lockdown is executed. IMA is considered as another kind of
signature appraising method.
If kexec kernel image has signature/crypto/key, it has to go through the
signature verification and pass. Otherwise it's seen as verification
failure, and won't be loaded.
Seems kexec kernel image with an unqualified signature is even worse
than those w/o signature at all, this sounds very unreasonable. E.g.
If people get a unsigned kernel to load, or a kernel signed with expired
key, which one is more dangerous?
So, here, let's simplify the logic to improve code readability. If the
KEXEC_SIG_FORCE enabled or kexec lockdown enabled, signature
verification is mandated. Otherwise, we lift the bar for any kernel
image.
Link: http://lkml.kernel.org/r/20200602045952.27487-1-lijiang@redhat.com
Signed-off-by: Lianbo Jiang <lijiang@redhat.com>
Reviewed-by: Jiri Bohac <jbohac@suse.cz>
Acked-by: Dave Young <dyoung@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Matthew Garrett <mjg59@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull networking fixes from David Miller:
1) Don't insert ESP trailer twice in IPSEC code, from Huy Nguyen.
2) The default crypto algorithm selection in Kconfig for IPSEC is out
of touch with modern reality, fix this up. From Eric Biggers.
3) bpftool is missing an entry for BPF_MAP_TYPE_RINGBUF, from Andrii
Nakryiko.
4) Missing init of ->frame_sz in xdp_convert_zc_to_xdp_frame(), from
Hangbin Liu.
5) Adjust packet alignment handling in ax88179_178a driver to match
what the hardware actually does. From Jeremy Kerr.
6) register_netdevice can leak in the case one of the notifiers fail,
from Yang Yingliang.
7) Use after free in ip_tunnel_lookup(), from Taehee Yoo.
8) VLAN checks in sja1105 DSA driver need adjustments, from Vladimir
Oltean.
9) tg3 driver can sleep forever when we get enough EEH errors, fix from
David Christensen.
10) Missing {READ,WRITE}_ONCE() annotations in various Intel ethernet
drivers, from Ciara Loftus.
11) Fix scanning loop break condition in of_mdiobus_register(), from
Florian Fainelli.
12) MTU limit is incorrect in ibmveth driver, from Thomas Falcon.
13) Endianness fix in mlxsw, from Ido Schimmel.
14) Use after free in smsc95xx usbnet driver, from Tuomas Tynkkynen.
15) Missing bridge mrp configuration validation, from Horatiu Vultur.
16) Fix circular netns references in wireguard, from Jason A. Donenfeld.
17) PTP initialization on recovery is not done properly in qed driver,
from Alexander Lobakin.
18) Endian conversion of L4 ports in filters of cxgb4 driver is wrong,
from Rahul Lakkireddy.
19) Don't clear bound device TX queue of socket prematurely otherwise we
get problems with ktls hw offloading, from Tariq Toukan.
20) ipset can do atomics on unaligned memory, fix from Russell King.
21) Align ethernet addresses properly in bridging code, from Thomas
Martitz.
22) Don't advertise ipv4 addresses on SCTP sockets having ipv6only set,
from Marcelo Ricardo Leitner.
* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (149 commits)
rds: transport module should be auto loaded when transport is set
sch_cake: fix a few style nits
sch_cake: don't call diffserv parsing code when it is not needed
sch_cake: don't try to reallocate or unshare skb unconditionally
ethtool: fix error handling in linkstate_prepare_data()
wil6210: account for napi_gro_receive never returning GRO_DROP
hns: do not cast return value of napi_gro_receive to null
socionext: account for napi_gro_receive never returning GRO_DROP
wireguard: receive: account for napi_gro_receive never returning GRO_DROP
vxlan: fix last fdb index during dump of fdb with nhid
sctp: Don't advertise IPv4 addresses if ipv6only is set on the socket
tc-testing: avoid action cookies with odd length.
bpf: tcp: bpf_cubic: fix spurious HYSTART_DELAY exit upon drop in min RTT
tcp_cubic: fix spurious HYSTART_DELAY exit upon drop in min RTT
net: dsa: sja1105: fix tc-gate schedule with single element
net: dsa: sja1105: recalculate gating subschedule after deleting tc-gate rules
net: dsa: sja1105: unconditionally free old gating config
net: dsa: sja1105: move sja1105_compose_gating_subschedule at the top
net: macb: free resources on failure path of at91ether_open()
net: macb: call pm_runtime_put_sync on failure path
...
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
"Four small fixes:
- Fix a ringbuffer bug for nested events having time go backwards
- Fix a config dependency for boot time tracing to depend on
synthetic events instead of histograms.
- Fix trigger format parsing to handle multiple spaces
- Fix bootconfig to handle failures in multiple events"
* tag 'trace-v5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/boottime: Fix kprobe multiple events
tracing: Fix event trigger to accept redundant spaces
tracing/boot: Fix config dependency for synthedic event
ring-buffer: Zero out time extend if it is nested and not absolute
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KCSAN reported data race reading and writing nr_threads and max_threads.
The data race is intentional and benign. This is obvious from the comment
above it and based on general consensus when discussing this issue. So
there's no need for any heavy atomic or *_ONCE() machinery here.
In accordance with the newly introduced data_race() annotation consensus,
mark the offending line with data_race(). Here it's actually useful not
just to silence KCSAN but to also clearly communicate that the race is
intentional. This is especially helpful since nr_threads is otherwise
protected by tasklist_lock.
BUG: KCSAN: data-race in copy_process / copy_process
write to 0xffffffff86205cf8 of 4 bytes by task 14779 on cpu 1:
copy_process+0x2eba/0x3c40 kernel/fork.c:2273
_do_fork+0xfe/0x7a0 kernel/fork.c:2421
__do_sys_clone kernel/fork.c:2576 [inline]
__se_sys_clone kernel/fork.c:2557 [inline]
__x64_sys_clone+0x130/0x170 kernel/fork.c:2557
do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x44/0xa9
read to 0xffffffff86205cf8 of 4 bytes by task 6944 on cpu 0:
copy_process+0x94d/0x3c40 kernel/fork.c:1954
_do_fork+0xfe/0x7a0 kernel/fork.c:2421
__do_sys_clone kernel/fork.c:2576 [inline]
__se_sys_clone kernel/fork.c:2557 [inline]
__x64_sys_clone+0x130/0x170 kernel/fork.c:2557
do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x44/0xa9
Link: https://groups.google.com/forum/#!msg/syzkaller-upstream-mo
deration/thvp7AHs5Ew/aPdYLXfYBQAJ
Reported-by: syzbot+52fced2d288f8ecd2b20@syzkaller.appspotmail.com
Signed-off-by: Zefan Li <lizefan@huawei.com>
Signed-off-by: Weilong Chen <chenweilong@huawei.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Marco Elver <elver@google.com>
[christian.brauner@ubuntu.com: rewrite commit message]
Link: https://lore.kernel.org/r/20200623041240.154294-1-chenweilong@huawei.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
|
|
A KCSAN build revealed we have explicit annoations through atomic_*()
usage, switch to arch_atomic_*() for the respective functions.
vmlinux.o: warning: objtool: rcu_nmi_exit()+0x4d: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: rcu_dynticks_eqs_enter()+0x25: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: rcu_nmi_enter()+0x4f: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: rcu_dynticks_eqs_exit()+0x2a: call to __kcsan_check_access() leaves .noinstr.text section
vmlinux.o: warning: objtool: __rcu_is_watching()+0x25: call to __kcsan_check_access() leaves .noinstr.text section
Additionally, without the NOP in instrumentation_begin(), objtool would
not detect the lack of the 'else instrumentation_begin();' branch in
rcu_nmi_enter().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
|
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To ensure btf_ctx_access() is safe the verifier checks that the BTF
arg type is an int, enum, or pointer. When the function does the
BTF arg lookup it uses the calculation 'arg = off / 8' using the
fact that registers are 8B. This requires that the first arg is
in the first reg, the second in the second, and so on. However,
for __int128 the arg will consume two registers by default LLVM
implementation. So this will cause the arg layout assumed by the
'arg = off / 8' calculation to be incorrect.
Because __int128 is uncommon this patch applies the easiest fix and
will force int types to be sizeof(u64) or smaller so that they will
fit in a single register.
v2: remove unneeded parens per Andrii's feedback
Fixes: 9e15db66136a1 ("bpf: Implement accurate raw_tp context access via BTF")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andriin@fb.com>
Link: https://lore.kernel.org/bpf/159303723962.11287.13309537171132420717.stgit@john-Precision-5820-Tower
|
|
Implement call_cpuidle_s2idle() in analogy with call_cpuidle()
for the s2idle-specific idle state entry and invoke it from
cpuidle_idle_call() to make the s2idle-specific idle entry code
path look more similar to the "regular" idle entry one.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Chen Yu <yu.c.chen@intel.com>
|
|
While rounding up CPUs via NMIs, its possible that a rounded up CPU
maybe holding a console port lock leading to kgdb master CPU stuck in
a deadlock during invocation of console write operations. A similar
deadlock could also be possible while using synchronous breakpoints.
So in order to avoid such a deadlock, set oops_in_progress to encourage
the console drivers to disregard their internal spin locks: in the
current calling context the risk of deadlock is a bigger problem than
risks due to re-entering the console driver. We operate directly on
oops_in_progress rather than using bust_spinlocks() because the calls
bust_spinlocks() makes on exit are not appropriate for this calling
context.
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/1591264879-25920-4-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
|
|
Check if a console is enabled prior to invoking corresponding write
handler.
Suggested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/1591264879-25920-3-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
|
|
Re-factor kdb_printf() message write code in order to avoid duplication
of code and thereby increase readability.
Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/1591264879-25920-2-git-send-email-sumit.garg@linaro.org
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull thread fix from Christian Brauner:
"This fixes a regression introduced with 303cc571d107 ("nsproxy: attach
to namespaces via pidfds").
The LTP testsuite reported a regression where users would now see
EBADF returned instead of EINVAL when an fd was passed that referred
to an open file but the file was not a namespace file.
Fix this by continuing to report EINVAL and add a regression test"
* tag 'for-linus-2020-06-24' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
tests: test for setns() EINVAL regression
nsproxy: restore EINVAL for non-namespace file descriptor
|
|
Fix boottime kprobe events to report and abort after each failure when
adding probes.
As an example, when we try to set multiprobe kprobe events in
bootconfig like this:
ftrace.event.kprobes.vfsevents {
probes = "vfs_read $arg1 $arg2,,
!error! not reported;?", // leads to error
"vfs_write $arg1 $arg2"
}
This will not work as expected. After
commit da0f1f4167e3af69e ("tracing/boottime: Fix kprobe event API usage"),
the function trace_boot_add_kprobe_event will not produce any error
message when adding a probe fails at kprobe_event_gen_cmd_start.
Furthermore, we continue to add probes when kprobe_event_gen_cmd_end fails
(and kprobe_event_gen_cmd_start did not fail). In this case the function
even returns successfully when the last call to kprobe_event_gen_cmd_end
is successful.
The behaviour of reporting and aborting after failures is not
consistent.
The function trace_boot_add_kprobe_event now reports each failure and
stops adding probes immediately.
Link: https://lkml.kernel.org/r/20200618163301.25854-1-sascha.ortmann@stud.uni-hannover.de
Cc: stable@vger.kernel.org
Cc: linux-kernel@i4.cs.fau.de
Co-developed-by: Maximilian Werner <maximilian.werner96@gmail.com>
Fixes: da0f1f4167e3 ("tracing/boottime: Fix kprobe event API usage")
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Maximilian Werner <maximilian.werner96@gmail.com>
Signed-off-by: Sascha Ortmann <sascha.ortmann@stud.uni-hannover.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Fix the event trigger to accept redundant spaces in
the trigger input.
For example, these return -EINVAL
echo " traceon" > events/ftrace/print/trigger
echo "traceon if common_pid == 0" > events/ftrace/print/trigger
echo "disable_event:kmem:kmalloc " > events/ftrace/print/trigger
But these are hard to find what is wrong.
To fix this issue, use skip_spaces() to remove spaces
in front of actual tokens, and set NULL if there is no
token.
Link: http://lkml.kernel.org/r/159262476352.185015.5261566783045364186.stgit@devnote2
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: 85f2b08268c0 ("tracing: Add basic event trigger framework")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Since commit 726721a51838 ("tracing: Move synthetic events to
a separate file") decoupled synthetic event from histogram,
boot-time tracing also has to check CONFIG_SYNTH_EVENT instead
of CONFIG_HIST_TRIGGERS.
Link: http://lkml.kernel.org/r/159262475441.185015.5300725180746017555.stgit@devnote2
Fixes: 726721a51838 ("tracing: Move synthetic events to a separate file")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
bpf programs
This is a fix for a regression in commit 2c78ee898d8f ("bpf: Implement CAP_BPF").
Before the above commit it was possible to load network bpf programs
with just the CAP_SYS_ADMIN privilege.
The Android bpfloader happens to run in such a configuration (it has
SYS_ADMIN but not NET_ADMIN) and creates maps and loads bpf programs
for later use by Android's netd (which has NET_ADMIN but not SYS_ADMIN).
Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF")
Reported-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Link: https://lore.kernel.org/bpf/20200620212616.93894-1-zenczykowski@gmail.com
|
|
Currently, if a bpf program has more than one subprograms, each program will be
jitted separately. For programs with bpf-to-bpf calls the
prog->aux->num_exentries is not setup properly. For example, with
bpf_iter_netlink.c modified to force one function to be not inlined and with
CONFIG_BPF_JIT_ALWAYS_ON the following error is seen:
$ ./test_progs -n 3/3
...
libbpf: failed to load program 'iter/netlink'
libbpf: failed to load object 'bpf_iter_netlink'
libbpf: failed to load BPF skeleton 'bpf_iter_netlink': -4007
test_netlink:FAIL:bpf_iter_netlink__open_and_load skeleton open_and_load failed
#3/3 netlink:FAIL
The dmesg shows the following errors:
ex gen bug
which is triggered by the following code in arch/x86/net/bpf_jit_comp.c:
if (excnt >= bpf_prog->aux->num_exentries) {
pr_err("ex gen bug\n");
return -EFAULT;
}
This patch fixes the issue by computing proper num_exentries for each
subprogram before calling JIT.
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
|
|
Currently the ring buffer makes events that happen in interrupts that preempt
another event have a delta of zero. (Hopefully we can change this soon). But
this is to deal with the races of updating a global counter with lockless
and nesting functions updating deltas.
With the addition of absolute time stamps, the time extend didn't follow
this rule. A time extend can happen if two events happen longer than 2^27
nanoseconds appart, as the delta time field in each event is only 27 bits.
If that happens, then a time extend is injected with 2^59 bits of
nanoseconds to use (18 years). But if the 2^27 nanoseconds happen between
two events, and as it is writing the event, an interrupt triggers, it will
see the 2^27 difference as well and inject a time extend of its own. But a
recent change made the time extend logic not take into account the nesting,
and this can cause two time extend deltas to happen moving the time stamp
much further ahead than the current time. This gets all reset when the ring
buffer moves to the next page, but that can cause time to appear to go
backwards.
This was observed in a trace-cmd recording, and since the data is saved in a
file, with trace-cmd report --debug, it was possible to see that this indeed
did happen!
bash-52501 110d... 81778.908247: sched_switch: bash:52501 [120] S ==> swapper/110:0 [120] [12770284:0x2e8:64]
<idle>-0 110d... 81778.908757: sched_switch: swapper/110:0 [120] R ==> bash:52501 [120] [509947:0x32c:64]
TIME EXTEND: delta:306454770 length:0
bash-52501 110.... 81779.215212: sched_swap_numa: src_pid=52501 src_tgid=52388 src_ngid=52501 src_cpu=110 src_nid=2 dst_pid=52509 dst_tgid=52388 dst_ngid=52501 dst_cpu=49 dst_nid=1 [0:0x378:48]
TIME EXTEND: delta:306458165 length:0
bash-52501 110dNh. 81779.521670: sched_wakeup: migration/110:565 [0] success=1 CPU:110 [0:0x3b4:40]
and at the next page, caused the time to go backwards:
bash-52504 110d... 81779.685411: sched_switch: bash:52504 [120] S ==> swapper/110:0 [120] [8347057:0xfb4:64]
CPU:110 [SUBBUFFER START] [81779379165886:0x1320000]
<idle>-0 110dN.. 81779.379166: sched_wakeup: bash:52504 [120] success=1 CPU:110 [0:0x10:40]
<idle>-0 110d... 81779.379167: sched_switch: swapper/110:0 [120] R ==> bash:52504 [120] [1168:0x3c:64]
Link: https://lkml.kernel.org/r/20200622151815.345d1bf5@oasis.local.home
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: stable@vger.kernel.org
Fixes: dc4e2801d400b ("ring-buffer: Redefine the unimplemented RINGBUF_TYPE_TIME_STAMP")
Reported-by: Julia Lawall <julia.lawall@inria.fr>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Running a guest with a virtio-iommu protecting virtio devices
is broken since commit 515e5b6d90d4 ("dma-mapping: use vmap insted
of reimplementing it"). Before the conversion, the size was
page aligned in __get_vm_area_node(). Doing so fixes the
regression.
Fixes: 515e5b6d90d4 ("dma-mapping: use vmap insted of reimplementing it")
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
The dma coherent pool code needs genalloc. Move the select over
from DMA_REMAP, which doesn't actually need it.
Fixes: dbed452a078d ("dma-pool: decouple DMA_REMAP from DMA_COHERENT_POOL")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: David Rientjes <rientjes@google.com>
|
|
When a coherent mapping is created in dma_direct_alloc_pages(), it needs
to be decrypted if the device requires unencrypted DMA before returning.
Fixes: 3acac065508f ("dma-mapping: merge the generic remapping helpers into dma-direct")
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
|
|
This reverts commit 8ece3b3eb576a78d2e67ad4c3a80a39fa6708809.
This commit broke userspace. Bash uses ESPIPE to determine whether or
not the file should be read using "unbuffered I/O", which means reading
1 byte at a time instead of 128 bytes at a time. I used to use bash to
read through kmsg in a really quite nasty way:
while read -t 0.1 -r line 2>/dev/null || [[ $? -ne 142 ]]; do
echo "SARU $line"
done < /dev/kmsg
This will show all lines that can fit into the 128 byte buffer, and skip
lines that don't. That's pretty awful, but at least it worked.
With this change, bash now tries to do 1-byte reads, which means it
skips all the lines, which is worse than before.
Now, I don't really care very much about this, and I'm already look for
a workaround. But I did just spend an hour trying to figure out why my
scripts were broken. Either way, it makes no difference to me personally
whether this is reverted, but it might be something to consider. If you
declare that "trying to read /dev/kmsg with bash is terminally stupid
anyway," I might be inclined to agree with you. But do note that bash
uses lseek(fd, 0, SEEK_CUR)==>ESPIPE to determine whether or not it's
reading from a pipe.
Cc: Bruno Meneguele <bmeneg@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Petr Mladek <pmladek@suse.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fixes from Steven Rostedt:
- Have recordmcount work with > 64K sections (to support LTO)
- kprobe RCU fixes
- Correct a kprobe critical section with missing mutex
- Remove redundant arch_disarm_kprobe() call
- Fix lockup when kretprobe triggers within kprobe_flush_task()
- Fix memory leak in fetch_op_data operations
- Fix sleep in atomic in ftrace trace array sample code
- Free up memory on failure in sample trace array code
- Fix incorrect reporting of function_graph fields in format file
- Fix quote within quote parsing in bootconfig
- Fix return value of bootconfig tool
- Add testcases for bootconfig tool
- Fix maybe uninitialized warning in ftrace pid file code
- Remove unused variable in tracing_iter_reset()
- Fix some typos
* tag 'trace-v5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Fix maybe-uninitialized compiler warning
tools/bootconfig: Add testcase for show-command and quotes test
tools/bootconfig: Fix to return 0 if succeeded to show the bootconfig
tools/bootconfig: Fix to use correct quotes for value
proc/bootconfig: Fix to use correct quotes for value
tracing: Remove unused event variable in tracing_iter_reset
tracing/probe: Fix memleak in fetch_op_data operations
trace: Fix typo in allocate_ftrace_ops()'s comment
tracing: Make ftrace packed events have align of 1
sample-trace-array: Remove trace_array 'sample-instance'
sample-trace-array: Fix sleeping function called from invalid context
kretprobe: Prevent triggering kretprobe from within kprobe_flush_task
kprobes: Remove redundant arch_disarm_kprobe() call
kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex
kprobes: Use non RCU traversal APIs on kprobe_tables if possible
kprobes: Suppress the suspicious RCU warning on kprobes
recordmcount: support >64k sections
|
|
Pull block fixes from Jens Axboe:
- Use import_uuid() where appropriate (Andy)
- bcache fixes (Coly, Mauricio, Zhiqiang)
- blktrace sparse warnings fix (Jan)
- blktrace concurrent setup fix (Luis)
- blkdev_get use-after-free fix (Jason)
- Ensure all blk-mq maps are updated (Weiping)
- Loop invalidate bdev fix (Zheng)
* tag 'block-5.8-2020-06-19' of git://git.kernel.dk/linux-block:
block: make function 'kill_bdev' static
loop: replace kill_bdev with invalidate_bdev
partitions/ldm: Replace uuid_copy() with import_uuid() where it makes sense
block: update hctx map when use multiple maps
blktrace: Avoid sparse warnings when assigning q->blk_trace
blktrace: break out of blktrace setup on concurrent calls
block: Fix use-after-free in blkdev_get()
trace/events/block.h: drop kernel-doc for dropped function parameter
blk-mq: Remove redundant 'return' statement
bcache: pr_info() format clean up in bcache_device_init()
bcache: use delayed kworker fo asynchronous devices registration
bcache: check and adjust logical block size for backing devices
bcache: fix potential deadlock problem in btree_gc_coalesce
|
|
Merge non-faulting memory access cleanups from Christoph Hellwig:
"Andrew and I decided to drop the patches implementing your suggested
rename of the probe_kernel_* and probe_user_* helpers from -mm as
there were way to many conflicts.
After -rc1 might be a good time for this as all the conflicts are
resolved now"
This also adds a type safety checking patch on top of the renaming
series to make the subtle behavioral difference between 'get_user()' and
'get_kernel_nofault()' less potentially dangerous and surprising.
* emailed patches from Christoph Hellwig <hch@lst.de>:
maccess: make get_kernel_nofault() check for minimal type compatibility
maccess: rename probe_kernel_address to get_kernel_nofault
maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault
maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault
|
|
A 5.7 kernel hangs during a tcrypt test of padata that waits for an AEAD
request to finish. This is only seen on large machines running many
concurrent requests.
The issue is that padata never serializes the request. The removal of
the reorder_objects atomic missed that the memory barrier in
padata_do_serial() depends on it.
Upgrade the barrier from smp_mb__after_atomic to smp_mb to get correct
ordering again.
Fixes: 3facced7aeed1 ("padata: remove reorder_objects")
Signed-off-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: linux-kernel@vger.kernel.org
Cc: <stable@vger.kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
|
|
During build compiler reports some 'false positive' warnings about
variables {'seq_ops', 'filtered_pids', 'other_pids'} may be used
uninitialized. This patch silences these warnings.
Also delete some useless spaces
Link: https://lkml.kernel.org/r/20200529141214.37648-1-pilgrimtao@gmail.com
Signed-off-by: Kaitao Cheng <pilgrimtao@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
|
|
Alexei Starovoitov says:
====================
pull-request: bpf 2020-06-17
The following pull-request contains BPF updates for your *net* tree.
We've added 10 non-merge commits during the last 2 day(s) which contain
a total of 14 files changed, 158 insertions(+), 59 deletions(-).
The main changes are:
1) Important fix for bpf_probe_read_kernel_str() return value, from Andrii.
2) [gs]etsockopt fix for large optlen, from Stanislav.
3) devmap allocation fix, from Toke.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
|
|
Pull dma-mapping fixes from Christoph Hellwig:
"Fixes for the SEV atomic pool (Geert Uytterhoeven and David Rientjes)"
* tag 'dma-mapping-5.8-3' of git://git.infradead.org/users/hch/dma-mapping:
dma-pool: decouple DMA_REMAP from DMA_COHERENT_POOL
dma-pool: fix too large DMA pools on medium memory size systems
|
|
Better describe what these functions do.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Better describe what these functions do.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Attaching to these hooks can break iptables because its optval is
usually quite big, or at least bigger than the current PAGE_SIZE limit.
David also mentioned some SCTP options can be big (around 256k).
For such optvals we expose only the first PAGE_SIZE bytes to
the BPF program. BPF program has two options:
1. Set ctx->optlen to 0 to indicate that the BPF's optval
should be ignored and the kernel should use original userspace
value.
2. Set ctx->optlen to something that's smaller than the PAGE_SIZE.
v5:
* use ctx->optlen == 0 with trimmed buffer (Alexei Starovoitov)
* update the docs accordingly
v4:
* use temporary buffer to avoid optval == optval_end == NULL;
this removes the corner case in the verifier that might assume
non-zero PTR_TO_PACKET/PTR_TO_PACKET_END.
v3:
* don't increase the limit, bypass the argument
v2:
* proper comments formatting (Jakub Kicinski)
Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Link: https://lore.kernel.org/bpf/20200617010416.93086-1-sdf@google.com
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Syzkaller discovered that creating a hash of type devmap_hash with a large
number of entries can hit the memory allocator limit for allocating
contiguous memory regions. There's really no reason to use kmalloc_array()
directly in the devmap code, so just switch it to the existing
bpf_map_area_alloc() function that is used elsewhere.
Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200616142829.114173-1-toke@redhat.com
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During recent refactorings, bpf_probe_read_kernel_str() started returning 0 on
success, instead of amount of data successfully read. This majorly breaks
applications relying on bpf_probe_read_kernel_str() and bpf_probe_read_str()
and their results. Fix this by returning actual number of bytes read.
Fixes: 8d92db5c04d1 ("bpf: rework the compat kernel probe handling")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200616050432.1902042-1-andriin@fb.com
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Mostly for historical reasons, q->blk_trace is assigned through xchg()
and cmpxchg() atomic operations. Although this is correct, sparse
complains about this because it violates rcu annotations since commit
c780e86dd48e ("blktrace: Protect q->blk_trace with RCU") which started
to use rcu for accessing q->blk_trace. Furthermore there's no real need
for atomic operations anymore since all changes to q->blk_trace happen
under q->blk_trace_mutex and since it also makes more sense to check if
q->blk_trace is set with the mutex held earlier.
So let's just replace xchg() with rcu_replace_pointer() and cmpxchg()
with explicit check and rcu_assign_pointer(). This makes the code more
efficient and sparse happy.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We use one blktrace per request_queue, that means one per the entire
disk. So we cannot run one blktrace on say /dev/vda and then /dev/vda1,
or just two calls on /dev/vda.
We check for concurrent setup only at the very end of the blktrace setup though.
If we try to run two concurrent blktraces on the same block device the
second one will fail, and the first one seems to go on. However when
one tries to kill the first one one will see things like this:
The kernel will show these:
```
debugfs: File 'dropped' in directory 'nvme1n1' already present!
debugfs: File 'msg' in directory 'nvme1n1' already present!
debugfs: File 'trace0' in directory 'nvme1n1' already present!
``
And userspace just sees this error message for the second call:
```
blktrace /dev/nvme1n1
BLKTRACESETUP(2) /dev/nvme1n1 failed: 5/Input/output error
```
The first userspace process #1 will also claim that the files
were taken underneath their nose as well. The files are taken
away form the first process given that when the second blktrace
fails, it will follow up with a BLKTRACESTOP and BLKTRACETEARDOWN.
This means that even if go-happy process #1 is waiting for blktrace
data, we *have* been asked to take teardown the blktrace.
This can easily be reproduced with break-blktrace [0] run_0005.sh test.
Just break out early if we know we're already going to fail, this will
prevent trying to create the files all over again, which we know still
exist.
[0] https://github.com/mcgrof/break-blktrace
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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__change_page_attr() can fail which will cause set_memory_encrypted() and
set_memory_decrypted() to return non-zero.
If the device requires unencrypted DMA memory and decryption fails, simply
free the memory and fail.
If attempting to re-encrypt in the failure path and that encryption fails,
there is no alternative other than to leak the memory.
Fixes: c10f07aa27da ("dma/direct: Handle force decryption for DMA coherent buffers in common code")
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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If arch_dma_set_uncached() fails after memory has been decrypted, it needs
to be re-encrypted before freeing.
Fixes: fa7e2247c572 ("dma-direct: make uncached_kernel_address more general")
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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dma_alloc_contiguous() does size >> PAGE_SHIFT and set_memory_decrypted()
works at page granularity. It's necessary to page align the allocation
size in dma_direct_alloc_pages() for consistent behavior.
This also fixes an issue when arch_dma_prep_coherent() is called on an
unaligned allocation size for dma_alloc_need_uncached() when
CONFIG_DMA_DIRECT_REMAP is disabled but CONFIG_ARCH_HAS_DMA_SET_UNCACHED
is enabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
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Signed-off-by: Christoph Hellwig <hch@lst.de>
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