In order to keep ahead of cases in the kernel where Control Flow
Integrity (CFI) may trip over function call casts, enabling
-Wcast-function-type is helpful. To that end, BPF_CAST_CALL causes
various warnings and is one of the last places in the kernel triggering
this warning.
Most places using BPF_CAST_CALL actually just want a void * to perform
math on. It's not actually performing a call, so just use a different
helper to get the void *, by way of the new BPF_CALL_IMM() helper, which
can clean up a common copy/paste idiom as well.
This change results in no object code difference.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://github.com/KSPP/linux/issues/20
Link: https://lore.kernel.org/lkml/CAEf4Bzb46=-J5Fxc3mMZ8JQPtK1uoE0q6+g6WPz53Cvx=CBEhw@mail.gmail.com
Link: https://lore.kernel.org/bpf/20210928230946.4062144-2-keescook@chromium.org
Daniel Borkmann says:
====================
pull-request: bpf 2021-09-28
The following pull-request contains BPF updates for your *net* tree.
We've added 10 non-merge commits during the last 14 day(s) which contain
a total of 11 files changed, 139 insertions(+), 53 deletions(-).
The main changes are:
1) Fix MIPS JIT jump code emission for too large offsets, from Piotr Krysiuk.
2) Fix x86 JIT atomic/fetch emission when dst reg maps to rax, from Johan Almbladh.
3) Fix cgroup_sk_alloc corner case when called from interrupt, from Daniel Borkmann.
4) Fix segfault in libbpf's linker for objects without BTF, from Kumar Kartikeya Dwivedi.
5) Fix bpf_jit_charge_modmem for applications with CAP_BPF, from Lorenz Bauer.
6) Fix return value handling for struct_ops BPF programs, from Hou Tao.
7) Various fixes to BPF selftests, from Jiri Benc.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
,
When CONFIG_MODULE_UNLOAD is disabled, the module->exit member
is not defined, causing a build failure:
kernel/module.c:4493:8: error: no member named 'exit' in 'struct module'
mod->exit = *exit;
add an #ifdef block around this.
Fixes: cf68fffb66 ("add support for Clang CFI")
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jessica Yu <jeyu@kernel.org>
If cgroup_sk_alloc() is called from interrupt context, then just assign the
root cgroup to skcd->cgroup. Prior to commit 8520e224f5 ("bpf, cgroups:
Fix cgroup v2 fallback on v1/v2 mixed mode") we would just return, and later
on in sock_cgroup_ptr(), we were NULL-testing the cgroup in fast-path, and
iff indeed NULL returning the root cgroup (v ?: &cgrp_dfl_root.cgrp). Rather
than re-adding the NULL-test to the fast-path we can just assign it once from
cgroup_sk_alloc() given v1/v2 handling has been simplified. The migration from
NULL test with returning &cgrp_dfl_root.cgrp to assigning &cgrp_dfl_root.cgrp
directly does /not/ change behavior for callers of sock_cgroup_ptr().
syzkaller was able to trigger a splat in the legacy netrom code base, where
the RX handler in nr_rx_frame() calls nr_make_new() which calls sk_alloc()
and therefore cgroup_sk_alloc() with in_interrupt() condition. Thus the NULL
skcd->cgroup, where it trips over on cgroup_sk_free() side given it expects
a non-NULL object. There are a few other candidates aside from netrom which
have similar pattern where in their accept-like implementation, they just call
to sk_alloc() and thus cgroup_sk_alloc() instead of sk_clone_lock() with the
corresponding cgroup_sk_clone() which then inherits the cgroup from the parent
socket. None of them are related to core protocols where BPF cgroup programs
are running from. However, in future, they should follow to implement a similar
inheritance mechanism.
Additionally, with a !CONFIG_CGROUP_NET_PRIO and !CONFIG_CGROUP_NET_CLASSID
configuration, the same issue was exposed also prior to 8520e224f5 due to
commit e876ecc67d ("cgroup: memcg: net: do not associate sock with unrelated
cgroup") which added the early in_interrupt() return back then.
Fixes: 8520e224f5 ("bpf, cgroups: Fix cgroup v2 fallback on v1/v2 mixed mode")
Fixes: e876ecc67d ("cgroup: memcg: net: do not associate sock with unrelated cgroup")
Reported-by: syzbot+df709157a4ecaf192b03@syzkaller.appspotmail.com
Reported-by: syzbot+533f389d4026d86a2a95@syzkaller.appspotmail.com
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tested-by: syzbot+df709157a4ecaf192b03@syzkaller.appspotmail.com
Tested-by: syzbot+533f389d4026d86a2a95@syzkaller.appspotmail.com
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/bpf/20210927123921.21535-1-daniel@iogearbox.net
When introducing CAP_BPF, bpf_jit_charge_modmem() was not changed to treat
programs with CAP_BPF as privileged for the purpose of JIT memory allocation.
This means that a program without CAP_BPF can block a program with CAP_BPF
from loading a program.
Fix this by checking bpf_capable() in bpf_jit_charge_modmem().
Fixes: 2c78ee898d ("bpf: Implement CAP_BPF")
Signed-off-by: Lorenz Bauer <lmb@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210922111153.19843-1-lmb@cloudflare.com
Convert all callers of mem_cgroup_charge() to call page_folio() on the
page they're currently passing in. Many of them will be converted to
use folios themselves soon.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Howells <dhowells@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
The verifier currently does not save the reg state when
spilling <8byte bounded scalar to the stack. The bpf program
will be incorrectly rejected when this scalar is refilled to
the reg and then used to offset into a packet header.
The later patch has a simplified bpf prog from a real use case
to demonstrate this case. The current work around is
to reparse the packet again such that this offset scalar
is close to where the packet data will be accessed to
avoid the spill. Thus, the header is parsed twice.
The llvm patch [1] will align the <8bytes spill to
the 8-byte stack address. This can simplify the verifier
support by avoiding to store multiple reg states for
each 8 byte stack slot.
This patch changes the verifier to save the reg state when
spilling <8bytes scalar to the stack. This reg state saving
is limited to spill aligned to the 8-byte stack address.
The current refill logic has already called coerce_reg_to_size(),
so coerce_reg_to_size() is not called on state->stack[spi].spilled_ptr
during spill.
When refilling in check_stack_read_fixed_off(), it checks
the refill size is the same as the number of bytes marked with
STACK_SPILL before restoring the reg state. When restoring
the reg state to state->regs[dst_regno], it needs
to avoid the state->regs[dst_regno].subreg_def being
over written because it has been marked by the check_reg_arg()
earlier [check_mem_access() is called after check_reg_arg() in
do_check()]. Reordering check_mem_access() and check_reg_arg()
will need a lot of changes in test_verifier's tests because
of the difference in verifier's error message. Thus, the
patch here is to save the state->regs[dst_regno].subreg_def
first in check_stack_read_fixed_off().
There are cases that the verifier needs to scrub the spilled slot
from STACK_SPILL to STACK_MISC. After this patch the spill is not always
in 8 bytes now, so it can no longer assume the other 7 bytes are always
marked as STACK_SPILL. In particular, the scrub needs to avoid marking
an uninitialized byte from STACK_INVALID to STACK_MISC. Otherwise, the
verifier will incorrectly accept bpf program reading uninitialized bytes
from the stack. A new helper scrub_spilled_slot() is created for this
purpose.
[1]: https://reviews.llvm.org/D109073
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210922004941.625398-1-kafai@fb.com
Every 8 bytes of the stack is tracked by a bpf_stack_state.
Within each bpf_stack_state, there is a 'u8 slot_type[8]' to track
the type of each byte. Verifier tests slot_type[0] == STACK_SPILL
to decide if the spilled reg state is saved. Verifier currently only
saves the reg state if the whole 8 bytes are spilled to the stack,
so checking the slot_type[7] is the same as checking slot_type[0].
The later patch will allow verifier to save the bounded scalar
reg also for <8 bytes spill. There is a llvm patch [1] to ensure
the <8 bytes spill will be 8-byte aligned, so checking
slot_type[7] instead of slot_type[0] is required.
While at it, this patch refactors the slot_type[0] == STACK_SPILL
test into a new function is_spilled_reg() and change the
slot_type[0] check to slot_type[7] check in there also.
[1] https://reviews.llvm.org/D109073
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210922004934.624194-1-kafai@fb.com
which failed to stop the timer when requested. That caused unexpected
signals to be sent to the process/thread causing malfunction.
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Merge tag 'timers-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Thomas Gleixner:
"A single fix for the recently introduced regression in posix CPU
timers which failed to stop the timer when requested. That caused
unexpected signals to be sent to the process/thread causing
malfunction"
* tag 'timers-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
posix-cpu-timers: Prevent spuriously armed 0-value itimer
- Work around a bad GIC integration on a Renesas platform which can't
handle byte-sized MMIO access
- Plug a potential memory leak in the GICv4 driver
- Fix a regression in the Armada 370-XP IPI code which was caused by
issuing EOI instack of ACK.
- A couple of small fixes here and there
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Merge tag 'irq-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq fixes from Thomas Gleixner:
"A set of fixes for interrupt chip drivers:
- Work around a bad GIC integration on a Renesas platform which can't
handle byte-sized MMIO access
- Plug a potential memory leak in the GICv4 driver
- Fix a regression in the Armada 370-XP IPI code which was caused by
issuing EOI instack of ACK.
- A couple of small fixes here and there"
* tag 'irq-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
irqchip/gic: Work around broken Renesas integration
irqchip/renesas-rza1: Use semicolons instead of commas
irqchip/gic-v3-its: Fix potential VPE leak on error
irqchip/goldfish-pic: Select GENERIC_IRQ_CHIP to fix build
irqchip/mbigen: Repair non-kernel-doc notation
irqdomain: Change the type of 'size' in __irq_domain_add() to be consistent
irqchip/armada-370-xp: Fix ack/eoi breakage
Documentation: Fix irq-domain.rst build warning
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Merge tag 'block-5.15-2021-09-25' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe:
- NVMe pull request via Christoph:
- keep ctrl->namespaces ordered (Christoph Hellwig)
- fix incorrect h2cdata pdu offset accounting in nvme-tcp (Sagi
Grimberg)
- handled updated hw_queues in nvme-fc more carefully (Daniel
Wagner, James Smart)
- md lock order fix (Christoph)
- fallocate locking fix (Ming)
- blktrace UAF fix (Zhihao)
- rq-qos bio tracking fix (Ming)
* tag 'block-5.15-2021-09-25' of git://git.kernel.dk/linux-block:
block: hold ->invalidate_lock in blkdev_fallocate
blktrace: Fix uaf in blk_trace access after removing by sysfs
block: don't call rq_qos_ops->done_bio if the bio isn't tracked
md: fix a lock order reversal in md_alloc
nvme: keep ctrl->namespaces ordered
nvme-tcp: fix incorrect h2cdata pdu offset accounting
nvme-fc: remove freeze/unfreeze around update_nr_hw_queues
nvme-fc: avoid race between time out and tear down
nvme-fc: update hardware queues before using them
- Work around a bad GIC integration on a Renesas platform, where the
interconnect cannot deal with byte-sized MMIO accesses
- Cleanup another Renesas driver abusing the comma operator
- Fix a potential GICv4 memory leak on an error path
- Make the type of 'size' consistent with the rest of the code in
__irq_domain_add()
- Fix a regression in the Armada 370-XP IPI path
- Fix the build for the obviously unloved goldfish-pic
- Some documentation fixes
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Merge tag 'irqchip-fixes-5.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms into irq/urgent
Pull irqchip fixes from Marc Zyngier:
- Work around a bad GIC integration on a Renesas platform, where the
interconnect cannot deal with byte-sized MMIO accesses
- Cleanup another Renesas driver abusing the comma operator
- Fix a potential GICv4 memory leak on an error path
- Make the type of 'size' consistent with the rest of the code in
__irq_domain_add()
- Fix a regression in the Armada 370-XP IPI path
- Fix the build for the obviously unloved goldfish-pic
- Some documentation fixes
Link: https://lore.kernel.org/r/20210924090933.2766857-1-maz@kernel.org
net/mptcp/protocol.c
977d293e23 ("mptcp: ensure tx skbs always have the MPTCP ext")
efe686ffce ("mptcp: ensure tx skbs always have the MPTCP ext")
same patch merged in both trees, keep net-next.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Resetting/stopping an itimer eventually leads to it being reprogrammed
with an actual "0" value. As a result the itimer expires on the next
tick, triggering an unexpected signal.
To fix this, make sure that
struct signal_struct::it[CPUCLOCK_PROF/VIRT]::expires is set to 0 when
setitimer() passes a 0 it_value, indicating that the timer must stop.
Fixes: 406dd42bd1 ("posix-cpu-timers: Force next expiration recalc after itimer reset")
Reported-by: Victor Stinner <vstinner@redhat.com>
Reported-by: Chris Hixon <linux-kernel-bugs@hixontech.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210913145332.232023-1-frederic@kernel.org
Invoke rseq_handle_notify_resume() from tracehook_notify_resume() now
that the two function are always called back-to-back by architectures
that have rseq. The rseq helper is stubbed out for architectures that
don't support rseq, i.e. this is a nop across the board.
Note, tracehook_notify_resume() is horribly named and arguably does not
belong in tracehook.h as literally every line of code in it has nothing
to do with tracing. But, that's been true since commit a42c6ded82
("move key_repace_session_keyring() into tracehook_notify_resume()")
first usurped tracehook_notify_resume() back in 2012. Punt cleaning that
mess up to future patches.
No functional change intended.
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210901203030.1292304-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Invoke rseq's NOTIFY_RESUME handler when processing the flag prior to
transferring to a KVM guest, which is roughly equivalent to an exit to
userspace and processes many of the same pending actions. While the task
cannot be in an rseq critical section as the KVM path is reachable only
by via ioctl(KVM_RUN), the side effects that apply to rseq outside of a
critical section still apply, e.g. the current CPU needs to be updated if
the task is migrated.
Clearing TIF_NOTIFY_RESUME without informing rseq can lead to segfaults
and other badness in userspace VMMs that use rseq in combination with KVM,
e.g. due to the CPU ID being stale after task migration.
Fixes: 72c3c0fe54 ("x86/kvm: Use generic xfer to guest work function")
Reported-by: Peter Foley <pefoley@google.com>
Bisected-by: Doug Evans <dje@google.com>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210901203030.1292304-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The 'size' is used in struct_size(domain, revmap, size) and its input
parameter type is 'size_t'(unsigned int).
Changing the size to 'unsigned int' to make the type consistent.
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210916025203.44841-1-cuibixuan@huawei.com
It was found that the following warning was displayed when remounting
controllers from cgroup v2 to v1:
[ 8042.997778] WARNING: CPU: 88 PID: 80682 at kernel/cgroup/cgroup.c:3130 cgroup_apply_control_disable+0x158/0x190
:
[ 8043.091109] RIP: 0010:cgroup_apply_control_disable+0x158/0x190
[ 8043.096946] Code: ff f6 45 54 01 74 39 48 8d 7d 10 48 c7 c6 e0 46 5a a4 e8 7b 67 33 00 e9 41 ff ff ff 49 8b 84 24 e8 01 00 00 0f b7 40 08 eb 95 <0f> 0b e9 5f ff ff ff 48 83 c4 08 5b 5d 41 5c 41 5d 41 5e 41 5f c3
[ 8043.115692] RSP: 0018:ffffba8a47c23d28 EFLAGS: 00010202
[ 8043.120916] RAX: 0000000000000036 RBX: ffffffffa624ce40 RCX: 000000000000181a
[ 8043.128047] RDX: ffffffffa63c43e0 RSI: ffffffffa63c43e0 RDI: ffff9d7284ee1000
[ 8043.135180] RBP: ffff9d72874c5800 R08: ffffffffa624b090 R09: 0000000000000004
[ 8043.142314] R10: ffffffffa624b080 R11: 0000000000002000 R12: ffff9d7284ee1000
[ 8043.149447] R13: ffff9d7284ee1000 R14: ffffffffa624ce70 R15: ffffffffa6269e20
[ 8043.156576] FS: 00007f7747cff740(0000) GS:ffff9d7a5fc00000(0000) knlGS:0000000000000000
[ 8043.164663] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 8043.170409] CR2: 00007f7747e96680 CR3: 0000000887d60001 CR4: 00000000007706e0
[ 8043.177539] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 8043.184673] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 8043.191804] PKRU: 55555554
[ 8043.194517] Call Trace:
[ 8043.196970] rebind_subsystems+0x18c/0x470
[ 8043.201070] cgroup_setup_root+0x16c/0x2f0
[ 8043.205177] cgroup1_root_to_use+0x204/0x2a0
[ 8043.209456] cgroup1_get_tree+0x3e/0x120
[ 8043.213384] vfs_get_tree+0x22/0xb0
[ 8043.216883] do_new_mount+0x176/0x2d0
[ 8043.220550] __x64_sys_mount+0x103/0x140
[ 8043.224474] do_syscall_64+0x38/0x90
[ 8043.228063] entry_SYSCALL_64_after_hwframe+0x44/0xae
It was caused by the fact that rebind_subsystem() disables
controllers to be rebound one by one. If more than one disabled
controllers are originally from the default hierarchy, it means that
cgroup_apply_control_disable() will be called multiple times for the
same default hierarchy. A controller may be killed by css_kill() in
the first round. In the second round, the killed controller may not be
completely dead yet leading to the warning.
To avoid this problem, we collect all the ssid's of controllers that
needed to be disabled from the default hierarchy and then disable them
in one go instead of one by one.
Fixes: 334c3679ec ("cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends")
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
In scenarios where containers are frequently created and deleted,
a large number of error logs maybe generated. The logs only show
which node is about to go over the max limit, not the node which
resource request failed. As misc.events has provided relevant
information, maybe we can remove this log.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Introduce misc.events to make it easier for us to understand
the pressure of resources. Currently only the 'max' event is
implemented, which indicates the times the resource is about
to exceeds the max limit.
Signed-off-by: Chunguang Xu <brookxu@tencent.com>
Reviewed-by: Vipin Sharma <vipinsh@google.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This patch adds basic audit io_uring filtering, using as much of the
existing audit filtering infrastructure as possible. In order to do
this we reuse the audit filter rule's syscall mask for the io_uring
operation and we create a new filter for io_uring operations as
AUDIT_FILTER_URING_EXIT/audit_filter_list[7].
Thanks to Richard Guy Briggs for his review, feedback, and work on
the corresponding audit userspace changes.
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch adds basic auditing to io_uring operations, regardless of
their context. This is accomplished by allocating audit_context
structures for the io-wq worker and io_uring SQPOLL kernel threads
as well as explicitly auditing the io_uring operations in
io_issue_sqe(). Individual io_uring operations can bypass auditing
through the "audit_skip" field in the struct io_op_def definition for
the operation; although great care must be taken so that security
relevant io_uring operations do not bypass auditing; please contact
the audit mailing list (see the MAINTAINERS file) with any questions.
The io_uring operations are audited using a new AUDIT_URINGOP record,
an example is shown below:
type=UNKNOWN[1336] msg=audit(1631800225.981:37289):
uring_op=19 success=yes exit=0 items=0 ppid=15454 pid=15681
uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0
subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
key=(null)
Thanks to Richard Guy Briggs for review and feedback.
Signed-off-by: Paul Moore <paul@paul-moore.com>
This patch cleans up some of our audit_context handling by
abstracting out the reset and return code fixup handling to dedicated
functions. Not only does this help make things easier to read and
inspect, it allows for easier reuse by future patches. We also
convert the simple audit_context->in_syscall flag into an enum which
can be used to by future patches to indicate a calling context other
than the syscall context.
Thanks to Richard Guy Briggs for review and feedback.
Acked-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
The support for misrouted IRQs is used on old / legacy systems and is
not feasible on PREEMPT_RT.
Polling for interrupts reduces the overall system performance.
Additionally the interrupt latency depends on the polling frequency and
delays are not desired for real time workloads.
Disable IRQ polling on PREEMPT_RT and let the user know that it is not
enabled. The compiler will optimize the real fixup/poll code out.
[ bigeasy: Update changelog and switch to IS_ENABLED() ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210917223841.c6j6jcaffojrnot3@linutronix.de
checked and then reread which makes all the checks invalid. Reuse the
already read value instead.
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Merge tag 'perf-urgent-2021-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf event fix from Thomas Gleixner:
"A single fix for the perf core where a value read with READ_ONCE() was
checked and then reread which makes all the checks invalid. Reuse the
already read value instead"
* tag 'perf-urgent-2021-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
events: Reuse value read using READ_ONCE instead of re-reading it
- Make the fast path reader ordering guarantees correct.
- Code reshuffling to make the fix simpler.
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Merge tag 'locking-urgent-2021-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fixes from Thomas Gleixner:
"A set of updates for the RT specific reader/writer locking base code:
- Make the fast path reader ordering guarantees correct.
- Code reshuffling to make the fix simpler"
[ This plays ugly games with atomic_add_return_release() because we
don't have a plain atomic_add_release(), and should really be cleaned
up, I think - Linus ]
* tag 'locking-urgent-2021-09-19' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rwbase: Take care of ordering guarantee for fastpath reader
locking/rwbase: Extract __rwbase_write_trylock()
locking/rwbase: Properly match set_and_save_state() to restore_state()
This helper is meant to be "bpf_trace_printk, but with proper vararg
support". Follow bpf_snprintf's example and take a u64 pseudo-vararg
array. Write to /sys/kernel/debug/tracing/trace_pipe using the same
mechanism as bpf_trace_printk. The functionality of this helper was
requested in the libbpf issue tracker [0].
[0] Closes: https://github.com/libbpf/libbpf/issues/315
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210917182911.2426606-4-davemarchevsky@fb.com
MAX_SNPRINTF_VARARGS and MAX_SEQ_PRINTF_VARARGS are used by bpf helpers
bpf_snprintf and bpf_seq_printf to limit their varargs. Both call into
bpf_bprintf_prepare for print formatting logic and have convenience
macros in libbpf (BPF_SNPRINTF, BPF_SEQ_PRINTF) which use the same
helper macros to convert varargs to a byte array.
Changing shared functionality to support more varargs for either bpf
helper would affect the other as well, so let's combine the _VARARGS
macros to make this more obvious.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20210917182911.2426606-2-davemarchevsky@fb.com
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-09-17
We've added 63 non-merge commits during the last 12 day(s) which contain
a total of 65 files changed, 2653 insertions(+), 751 deletions(-).
The main changes are:
1) Streamline internal BPF program sections handling and
bpf_program__set_attach_target() in libbpf, from Andrii.
2) Add support for new btf kind BTF_KIND_TAG, from Yonghong.
3) Introduce bpf_get_branch_snapshot() to capture LBR, from Song.
4) IMUL optimization for x86-64 JIT, from Jie.
5) xsk selftest improvements, from Magnus.
6) Introduce legacy kprobe events support in libbpf, from Rafael.
7) Access hw timestamp through BPF's __sk_buff, from Vadim.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (63 commits)
selftests/bpf: Fix a few compiler warnings
libbpf: Constify all high-level program attach APIs
libbpf: Schedule open_opts.attach_prog_fd deprecation since v0.7
selftests/bpf: Switch fexit_bpf2bpf selftest to set_attach_target() API
libbpf: Allow skipping attach_func_name in bpf_program__set_attach_target()
libbpf: Deprecated bpf_object_open_opts.relaxed_core_relocs
selftests/bpf: Stop using relaxed_core_relocs which has no effect
libbpf: Use pre-setup sec_def in libbpf_find_attach_btf_id()
bpf: Update bpf_get_smp_processor_id() documentation
libbpf: Add sphinx code documentation comments
selftests/bpf: Skip btf_tag test if btf_tag attribute not supported
docs/bpf: Add documentation for BTF_KIND_TAG
selftests/bpf: Add a test with a bpf program with btf_tag attributes
selftests/bpf: Test BTF_KIND_TAG for deduplication
selftests/bpf: Add BTF_KIND_TAG unit tests
selftests/bpf: Change NAME_NTH/IS_NAME_NTH for BTF_KIND_TAG format
selftests/bpf: Test libbpf API function btf__add_tag()
bpftool: Add support for BTF_KIND_TAG
libbpf: Add support for BTF_KIND_TAG
libbpf: Rename btf_{hash,equal}_int to btf_{hash,equal}_int_tag
...
====================
Link: https://lore.kernel.org/r/20210917173738.3397064-1-ast@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
- page align size in sparc32 arch_dma_alloc (Andreas Larsson)
- tone down a new dma-debug message (Hamza Mahfooz)
- fix the kerneldoc for dma_map_sg_attrs (me)
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Merge tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mapping
Pull dma-mapping fixes from Christoph Hellwig:
- page align size in sparc32 arch_dma_alloc (Andreas Larsson)
- tone down a new dma-debug message (Hamza Mahfooz)
- fix the kerneldoc for dma_map_sg_attrs (me)
* tag 'dma-mapping-5.15-1' of git://git.infradead.org/users/hch/dma-mapping:
sparc32: page align size in arch_dma_alloc
dma-debug: prevent an error message from causing runtime problems
dma-mapping: fix the kerneldoc for dma_map_sg_attrs
Comments in wait-type checks be improved by mentioning the
PREEPT_RT kernel configure option.
Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lkml.kernel.org/r/20210811025920.20751-1-zhouzhouyi@gmail.com
lock_is_held_type(, 1) detects acquired read locks. It only recognized
locks acquired with lock_acquire_shared(). Read locks acquired with
lock_acquire_shared_recursive() are not recognized because a `2' is
stored as the read value.
Rework the check to additionally recognise lock's read value one and two
as a read held lock.
Fixes: e918188611 ("locking: More accurate annotations for read_lock()")
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Acked-by: Waiman Long <longman@redhat.com>
Link: https://lkml.kernel.org/r/20210903084001.lblecrvz4esl4mrr@linutronix.de
i915 will soon gain an eviction path that trylock a whole lot of locks
for eviction, getting dmesg failures like below:
BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48 max: 48!
48 locks held by i915_selftest/5776:
#0: ffff888101a79240 (&dev->mutex){....}-{3:3}, at: __driver_attach+0x88/0x160
#1: ffffc900009778c0 (reservation_ww_class_acquire){+.+.}-{0:0}, at: i915_vma_pin.constprop.63+0x39/0x1b0 [i915]
#2: ffff88800cf74de8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_vma_pin.constprop.63+0x5f/0x1b0 [i915]
#3: ffff88810c7f9e38 (&vm->mutex/1){+.+.}-{3:3}, at: i915_vma_pin_ww+0x1c4/0x9d0 [i915]
#4: ffff88810bad5768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
#5: ffff88810bad60e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
...
#46: ffff88811964d768 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
#47: ffff88811964e0e8 (reservation_ww_class_mutex){+.+.}-{3:3}, at: i915_gem_evict_something+0x110/0x860 [i915]
INFO: lockdep is turned off.
Fixing eviction to nest into ww_class_acquire is a high priority, but
it requires a rework of the entire driver, which can only be done one
step at a time.
As an intermediate solution, add an acquire context to
ww_mutex_trylock, which allows us to do proper nesting annotations on
the trylocks, making the above lockdep splat disappear.
This is also useful in regulator_lock_nested, which may avoid dropping
regulator_nesting_mutex in the uncontended path, so use it there.
TTM may be another user for this, where we could lock a buffer in a
fastpath with list locks held, without dropping all locks we hold.
[peterz: rework actual ww_mutex_trylock() implementations]
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YUBGPdDDjKlxAuXJ@hirez.programming.kicks-ass.net
With enabled threaded interrupts the nouveau driver reported the
following:
| Chain exists of:
| &mm->mmap_lock#2 --> &device->mutex --> &cpuset_rwsem
|
| Possible unsafe locking scenario:
|
| CPU0 CPU1
| ---- ----
| lock(&cpuset_rwsem);
| lock(&device->mutex);
| lock(&cpuset_rwsem);
| lock(&mm->mmap_lock#2);
The device->mutex is nvkm_device::mutex.
Unblocking the lockchain at `cpuset_rwsem' is probably the easiest
thing to do. Move the priority assignment to the start of the newly
created thread.
Fixes: 710da3c8ea ("sched/core: Prevent race condition between cpuset and __sched_setscheduler()")
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: Patch description]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/a23a826af7c108ea5651e73b8fbae5e653f16e86.camel@gmx.de
On RT kernels, the use of migrate_disable()/migrate_enable() is sufficient
to guarantee a task isn't moved to another CPU. Update the
irq_set_irqchip_state() documentation to reflect this.
Signed-off-by: Josh Cartwright <joshc@ni.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210917103055.92150-1-bigeasy@linutronix.de
When running scftorture as a module, any scf_torture_init() issues will be
reflected in the error code from modprobe or insmod, as the case may be.
However, these error codes are not available when running scftorture
built-in, for example, when using the kvm.sh script. This commit
therefore adds WARN_ON_ONCE() to allow distinguishing scf_torture_init()
errors when running scftorture built-in.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Currently, only those IPIs that invoke scftorture's scf_handler()
IPI handler function are counted. This means that runs exercising
only scftorture.weight_resched will look like they have made no forward
progress, resulting in "GP HANG" complaints from the rcutorture scripting.
This commit therefore increments the scf_invoked_count per-CPU counter
immediately after calling resched_cpu().
Fixes: 1ac78b49d6 ("scftorture: Add an alternative IPI vector")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The "all zero weights makes no sense" error is emitted even when
scftorture.weight_resched is non-zero because it was left out of
the enclosing "if" condition. This commit adds it in.
Fixes: 1ac78b49d6 ("scftorture: Add an alternative IPI vector")
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
If (say) a 10-hour scftorture run is started, but the module parameters
are so nonsensical that the run doesn't even start, then scftorture will
wait the full ten hours when run built into a guest OS. This commit
therefore shuts down the system in this case so that the error is reported
immediately instead of ten hours hence.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit reworks the weighting calculations to allow zero to
be specified to disable a given weight. For example, specifying the
scftorture.weight_resched=0 kernel boot parameter without specifying a
non-zero value for any of the other scftorture.weight_* parameters would
provide the default weights for the others, but would refrain from doing
any resched-based IPIs.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Since commit aa40c138cc ("rcu: Report QS for outermost PREEMPT=n
rcu_read_unlock() for strict GPs") the function rcu_read_unlock_strict()
is invoked by the inlined rcu_read_unlock() function. However,
rcu_read_unlock_strict() is an empty function in production kernels,
which are built with CONFIG_RCU_STRICT_GRACE_PERIOD=n.
There is a mention of rcu_read_unlock_strict() in the BPF verifier,
but this is in a deny-list, meaning that BPF does not care whether
rcu_read_unlock_strict() is ever called.
This commit therefore provides a slight performance improvement
by hoisting the check of CONFIG_RCU_STRICT_GRACE_PERIOD from
rcu_read_unlock_strict() into rcu_read_unlock(), thus avoiding the
pointless call to an empty function.
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The cond_resched_rcu_qs() function no longer exists, despite being mentioned
several times in kernel/rcu/tasks.h. This commit therefore updates it to
the current cond_resched_tasks_rcu_qs().
Reported-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
The trc_wait_for_one_reader() function is called at multiple stages
of trace rcu-tasks GP function, rcu_tasks_wait_gp():
- First, it is called as part of per task function -
rcu_tasks_trace_pertask(), for all non-idle tasks. As part of per task
processing, this function add the task in the holdout list and if the
task is currently running on a CPU, it sends IPI to the task's CPU.
The IPI handler takes action depending on whether task is in trace
rcu-tasks read side critical section or not:
- a. If the task is in trace rcu-tasks read side critical section
(t->trc_reader_nesting != 0), the IPI handler sets the task's
->trc_reader_special.b.need_qs, so that this task notifies exit
from its outermost read side critical section (by decrementing
trc_n_readers_need_end) to the GP handling function.
trc_wait_for_one_reader() also increments trc_n_readers_need_end,
so that the trace rcu-tasks GP handler function waits for this
task's read side exit notification. The IPI handler also sets
t->trc_reader_checked to true, and no further IPIs are sent for
this task, for this trace rcu-tasks grace period and this
task can be removed from holdout list.
- b. If the task is in the process of exiting its trace rcu-tasks
read side critical section, (t->trc_reader_nesting < 0), defer
this task's processing to future calls to trc_wait_for_one_reader().
- c. If task is not in rcu-task read side critical section,
t->trc_reader_nesting == 0, ->trc_reader_checked is set for this
task, so that this task is removed from holdout list.
- Second, trc_wait_for_one_reader() is called as part of post scan, in
function rcu_tasks_trace_postscan(), for all idle tasks.
- Third, in function check_all_holdout_tasks_trace(), this function is
called for each task in the holdout list, but only if there isn't
a pending IPI for the task (->trc_ipi_to_cpu == -1). This function
removed the task from holdout list, if IPI handler has completed the
required work, to ensure that the current trace rcu-tasks grace period
either waits for this task, or this task is not in a trace rcu-tasks
read side critical section.
Now, considering the scenario where smp_call_function_single() fails in
first case, inside rcu_tasks_trace_pertask(). In this case,
->trc_ipi_to_cpu is set to the current CPU for that task. This will
result in trc_wait_for_one_reader() getting skipped in third case,
inside check_all_holdout_tasks_trace(), for this task. This further
results in ->trc_reader_checked never getting set for this task,
and the task not getting removed from holdout list. This can cause
the current trace rcu-tasks grace period to stall.
Fix the above problem, by resetting ->trc_ipi_to_cpu to -1, on
smp_call_function_single() failure, so that future IPI calls can
be send for this task.
Note that all three of the trc_wait_for_one_reader() function's
callers (rcu_tasks_trace_pertask(), rcu_tasks_trace_postscan(),
check_all_holdout_tasks_trace()) hold cpu_read_lock(). This means
that smp_call_function_single() cannot race with CPU hotplug, and thus
should never fail. Therefore, also add a warning in order to report
any such failure in case smp_call_function_single() grows some other
reason for failure.
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
call_rcu_tasks_trace() does have read-side primitives - rcu_read_lock_trace()
and rcu_read_unlock_trace(). Fix this information in the comments.
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
RCU tasks rude variant does not check whether the current
running context on a CPU is usermode. Read side critical section ends
on transition to usermode execution, by the virtue of usermode
execution being schedulable. Clarify this in comments for
call_rcu_tasks_rude() and synchronize_rcu_tasks_rude().
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Valid CPU numbers can be zero or greater, but the checks for
->trc_ipi_to_cpu and tick_nohz_full_cpu()'s argument are for strictly
greater than. This commit therefore corrects the check for no_hz_full
cpu in show_stalled_task_trace() so as to include cpu 0.
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
In check_all_holdout_tasks_trace(), firstreport is a pointer argument;
so, check the dereferenced value, instead of checking the pointer.
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
