[ Upstream commit e64746e74f ]
cpumask_of_node() can be called for NUMA_NO_NODE inside do_map_benchmark()
resulting in the following sanitizer report:
UBSAN: array-index-out-of-bounds in ./arch/x86/include/asm/topology.h:72:28
index -1 is out of range for type 'cpumask [64][1]'
CPU: 1 PID: 990 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #29
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:117)
ubsan_epilogue (lib/ubsan.c:232)
__ubsan_handle_out_of_bounds (lib/ubsan.c:429)
cpumask_of_node (arch/x86/include/asm/topology.h:72) [inline]
do_map_benchmark (kernel/dma/map_benchmark.c:104)
map_benchmark_ioctl (kernel/dma/map_benchmark.c:246)
full_proxy_unlocked_ioctl (fs/debugfs/file.c:333)
__x64_sys_ioctl (fs/ioctl.c:890)
do_syscall_64 (arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Use cpumask_of_node() in place when binding a kernel thread to a cpuset
of a particular node.
Note that the provided node id is checked inside map_benchmark_ioctl().
It's just a NUMA_NO_NODE case which is not handled properly later.
Found by Linux Verification Center (linuxtesting.org).
Fixes: 65789daa80 ("dma-mapping: add benchmark support for streaming DMA APIs")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Barry Song <baohua@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1ff05e723f ]
While validating node ids in map_benchmark_ioctl(), node_possible() may
be provided with invalid argument outside of [0,MAX_NUMNODES-1] range
leading to:
BUG: KASAN: wild-memory-access in map_benchmark_ioctl (kernel/dma/map_benchmark.c:214)
Read of size 8 at addr 1fffffff8ccb6398 by task dma_map_benchma/971
CPU: 7 PID: 971 Comm: dma_map_benchma Not tainted 6.9.0-rc6 #37
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Call Trace:
<TASK>
dump_stack_lvl (lib/dump_stack.c:117)
kasan_report (mm/kasan/report.c:603)
kasan_check_range (mm/kasan/generic.c:189)
variable_test_bit (arch/x86/include/asm/bitops.h:227) [inline]
arch_test_bit (arch/x86/include/asm/bitops.h:239) [inline]
_test_bit at (include/asm-generic/bitops/instrumented-non-atomic.h:142) [inline]
node_state (include/linux/nodemask.h:423) [inline]
map_benchmark_ioctl (kernel/dma/map_benchmark.c:214)
full_proxy_unlocked_ioctl (fs/debugfs/file.c:333)
__x64_sys_ioctl (fs/ioctl.c:890)
do_syscall_64 (arch/x86/entry/common.c:83)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Compare node ids with sane bounds first. NUMA_NO_NODE is considered a
special valid case meaning that benchmarking kthreads won't be bound to a
cpuset of a given node.
Found by Linux Verification Center (linuxtesting.org).
Fixes: 65789daa80 ("dma-mapping: add benchmark support for streaming DMA APIs")
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 49217ea147 ]
In the cgroup v2 CPU subsystem, assuming we have a
cgroup named 'test', and we set cpu.max and cpu.max.burst:
# echo 1000000 > /sys/fs/cgroup/test/cpu.max
# echo 1000000 > /sys/fs/cgroup/test/cpu.max.burst
then we check cpu.max and cpu.max.burst:
# cat /sys/fs/cgroup/test/cpu.max
1000000 100000
# cat /sys/fs/cgroup/test/cpu.max.burst
1000000
Next we set cpu.max again and check cpu.max and
cpu.max.burst:
# echo 2000000 > /sys/fs/cgroup/test/cpu.max
# cat /sys/fs/cgroup/test/cpu.max
2000000 100000
# cat /sys/fs/cgroup/test/cpu.max.burst
1000
... we find that the cpu.max.burst value changed unexpectedly.
In cpu_max_write(), the unit of the burst value returned
by tg_get_cfs_burst() is microseconds, while in cpu_max_write(),
the burst unit used for calculation should be nanoseconds,
which leads to the bug.
To fix it, get the burst value directly from tg->cfs_bandwidth.burst.
Fixes: f4183717b3 ("sched/fair: Introduce the burstable CFS controller")
Reported-by: Qixin Liao <liaoqixin@huawei.com>
Signed-off-by: Cheng Yu <serein.chengyu@huawei.com>
Signed-off-by: Zhang Qiao <zhangqiao22@huawei.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20240424132438.514720-1-serein.chengyu@huawei.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit be3a51e68f ]
root_domain::overutilized is only used for EAS(energy aware scheduler)
to decide whether to do load balance or not. It is not used if EAS
not possible.
Currently enqueue_task_fair and task_tick_fair accesses, sometime updates
this field. In update_sd_lb_stats it is updated often. This causes cache
contention due to true sharing and burns a lot of cycles. ::overload and
::overutilized are part of the same cacheline. Updating it often invalidates
the cacheline. That causes access to ::overload to slow down due to
false sharing. Hence add EAS check before accessing/updating this field.
EAS check is optimized at compile time or it is a static branch.
Hence it shouldn't cost much.
With the patch, both enqueue_task_fair and newidle_balance don't show
up as hot routines in perf profile.
6.8-rc4:
7.18% swapper [kernel.vmlinux] [k] enqueue_task_fair
6.78% s [kernel.vmlinux] [k] newidle_balance
+patch:
0.14% swapper [kernel.vmlinux] [k] enqueue_task_fair
0.00% swapper [kernel.vmlinux] [k] newidle_balance
While at it: trace_sched_overutilized_tp expect that second argument to
be bool. So do a int to bool conversion for that.
Fixes: 2802bf3cd9 ("sched/fair: Add over-utilization/tipping point indicator")
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Qais Yousef <qyousef@layalina.io>
Reviewed-by: Srikar Dronamraju <srikar@linux.ibm.com>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Link: https://lore.kernel.org/r/20240307085725.444486-2-sshegde@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 1dd1eff161 ]
Currently, the condition "__this_cpu_read(ksoftirqd) == current" is used to
invoke rcu_softirq_qs() in ksoftirqd tasks context for non-RT kernels.
This works correctly as long as the context is actually task context but
this condition is wrong when:
- the current task is ksoftirqd
- the task is interrupted in a RCU read side critical section
- __do_softirq() is invoked on return from interrupt
Syzkaller triggered the following scenario:
-> finish_task_switch()
-> put_task_struct_rcu_user()
-> call_rcu(&task->rcu, delayed_put_task_struct)
-> __kasan_record_aux_stack()
-> pfn_valid()
-> rcu_read_lock_sched()
<interrupt>
__irq_exit_rcu()
-> __do_softirq)()
-> if (!IS_ENABLED(CONFIG_PREEMPT_RT) &&
__this_cpu_read(ksoftirqd) == current)
-> rcu_softirq_qs()
-> RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map))
The rcu quiescent state is reported in the rcu-read critical section, so
the lockdep warning is triggered.
Fix this by splitting out the inner working of __do_softirq() into a helper
function which takes an argument to distinguish between ksoftirqd task
context and interrupted context and invoke it from the relevant call sites
with the proper context information and use that for the conditional
invocation of rcu_softirq_qs().
Reported-by: syzbot+dce04ed6d1438ad69656@syzkaller.appspotmail.com
Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240427102808.29356-1-qiang.zhang1211@gmail.com
Link: https://lore.kernel.org/lkml/8f281a10-b85a-4586-9586-5bbc12dc784f@paulmck-laptop/T/#mea8aba4abfcb97bbf499d169ce7f30c4cff1b0e3
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit c2274b908d upstream.
The reader code in rb_get_reader_page() swaps a new reader page into the
ring buffer by doing cmpxchg on old->list.prev->next to point it to the
new page. Following that, if the operation is successful,
old->list.next->prev gets updated too. This means the underlying
doubly-linked list is temporarily inconsistent, page->prev->next or
page->next->prev might not be equal back to page for some page in the
ring buffer.
The resize operation in ring_buffer_resize() can be invoked in parallel.
It calls rb_check_pages() which can detect the described inconsistency
and stop further tracing:
[ 190.271762] ------------[ cut here ]------------
[ 190.271771] WARNING: CPU: 1 PID: 6186 at kernel/trace/ring_buffer.c:1467 rb_check_pages.isra.0+0x6a/0xa0
[ 190.271789] Modules linked in: [...]
[ 190.271991] Unloaded tainted modules: intel_uncore_frequency(E):1 skx_edac(E):1
[ 190.272002] CPU: 1 PID: 6186 Comm: cmd.sh Kdump: loaded Tainted: G E 6.9.0-rc6-default #5 158d3e1e6d0b091c34c3b96bfd99a1c58306d79f
[ 190.272011] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552c-rebuilt.opensuse.org 04/01/2014
[ 190.272015] RIP: 0010:rb_check_pages.isra.0+0x6a/0xa0
[ 190.272023] Code: [...]
[ 190.272028] RSP: 0018:ffff9c37463abb70 EFLAGS: 00010206
[ 190.272034] RAX: ffff8eba04b6cb80 RBX: 0000000000000007 RCX: ffff8eba01f13d80
[ 190.272038] RDX: ffff8eba01f130c0 RSI: ffff8eba04b6cd00 RDI: ffff8eba0004c700
[ 190.272042] RBP: ffff8eba0004c700 R08: 0000000000010002 R09: 0000000000000000
[ 190.272045] R10: 00000000ffff7f52 R11: ffff8eba7f600000 R12: ffff8eba0004c720
[ 190.272049] R13: ffff8eba00223a00 R14: 0000000000000008 R15: ffff8eba067a8000
[ 190.272053] FS: 00007f1bd64752c0(0000) GS:ffff8eba7f680000(0000) knlGS:0000000000000000
[ 190.272057] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 190.272061] CR2: 00007f1bd6662590 CR3: 000000010291e001 CR4: 0000000000370ef0
[ 190.272070] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 190.272073] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[ 190.272077] Call Trace:
[ 190.272098] <TASK>
[ 190.272189] ring_buffer_resize+0x2ab/0x460
[ 190.272199] __tracing_resize_ring_buffer.part.0+0x23/0xa0
[ 190.272206] tracing_resize_ring_buffer+0x65/0x90
[ 190.272216] tracing_entries_write+0x74/0xc0
[ 190.272225] vfs_write+0xf5/0x420
[ 190.272248] ksys_write+0x67/0xe0
[ 190.272256] do_syscall_64+0x82/0x170
[ 190.272363] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 190.272373] RIP: 0033:0x7f1bd657d263
[ 190.272381] Code: [...]
[ 190.272385] RSP: 002b:00007ffe72b643f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 190.272391] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007f1bd657d263
[ 190.272395] RDX: 0000000000000002 RSI: 0000555a6eb538e0 RDI: 0000000000000001
[ 190.272398] RBP: 0000555a6eb538e0 R08: 000000000000000a R09: 0000000000000000
[ 190.272401] R10: 0000555a6eb55190 R11: 0000000000000246 R12: 00007f1bd6662500
[ 190.272404] R13: 0000000000000002 R14: 00007f1bd6667c00 R15: 0000000000000002
[ 190.272412] </TASK>
[ 190.272414] ---[ end trace 0000000000000000 ]---
Note that ring_buffer_resize() calls rb_check_pages() only if the parent
trace_buffer has recording disabled. Recent commit d78ab79270
("tracing: Stop current tracer when resizing buffer") causes that it is
now always the case which makes it more likely to experience this issue.
The window to hit this race is nonetheless very small. To help
reproducing it, one can add a delay loop in rb_get_reader_page():
ret = rb_head_page_replace(reader, cpu_buffer->reader_page);
if (!ret)
goto spin;
for (unsigned i = 0; i < 1U << 26; i++) /* inserted delay loop */
__asm__ __volatile__ ("" : : : "memory");
rb_list_head(reader->list.next)->prev = &cpu_buffer->reader_page->list;
.. and then run the following commands on the target system:
echo 1 > /sys/kernel/tracing/events/sched/sched_switch/enable
while true; do
echo 16 > /sys/kernel/tracing/buffer_size_kb; sleep 0.1
echo 8 > /sys/kernel/tracing/buffer_size_kb; sleep 0.1
done &
while true; do
for i in /sys/kernel/tracing/per_cpu/*; do
timeout 0.1 cat $i/trace_pipe; sleep 0.2
done
done
To fix the problem, make sure ring_buffer_resize() doesn't invoke
rb_check_pages() concurrently with a reader operating on the same
ring_buffer_per_cpu by taking its cpu_buffer->reader_lock.
Link: https://lore.kernel.org/linux-trace-kernel/20240517134008.24529-3-petr.pavlu@suse.com
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 659f451ff2 ("ring-buffer: Add integrity check at end of iter read")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
[ Fixed whitespace ]
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d53ad5d8b2 ]
All map redirect functions except XSK maps convert xdp_buff to xdp_frame
before enqueueing it. So move this conversion of out the map functions
and into xdp_do_redirect(). This removes a bit of duplicated code, but more
importantly it makes it possible to support caller-allocated xdp_frame
structures, which will be added in a subsequent commit.
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220103150812.87914-5-toke@redhat.com
Stable-dep-of: 5bcf0dcbf9 ("xdp: use flags field to disambiguate broadcast redirect")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 37eacb9f6e ]
Long ago a map file descriptor in a pseudo ldimm64 instruction could
only be present as an immediate value insn[0].imm, and thus this value
was used in a verbose verifier message printed when the file descriptor
wasn't valid. Since addition of BPF_PSEUDO_MAP_IDX_VALUE/BPF_PSEUDO_MAP_IDX
the insn[0].imm field can also contain an index pointing to the file
descriptor in the attr.fd_array array. However, if the file descriptor
is invalid, the verifier still prints the verbose message containing
value of insn[0].imm. Patch the verifier message to always print the
actual file descriptor value.
Fixes: 387544bfa2 ("bpf: Introduce fd_idx")
Signed-off-by: Anton Protopopov <aspsk@isovalent.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240412141100.3562942-1-aspsk@isovalent.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit fe42754b94 upstream.
Rename x86's to CPU_MITIGATIONS, define it in generic code, and force it
on for all architectures exception x86. A recent commit to turn
mitigations off by default if SPECULATION_MITIGATIONS=n kinda sorta
missed that "cpu_mitigations" is completely generic, whereas
SPECULATION_MITIGATIONS is x86-specific.
Rename x86's SPECULATIVE_MITIGATIONS instead of keeping both and have it
select CPU_MITIGATIONS, as having two configs for the same thing is
unnecessary and confusing. This will also allow x86 to use the knob to
manage mitigations that aren't strictly related to speculative
execution.
Use another Kconfig to communicate to common code that CPU_MITIGATIONS
is already defined instead of having x86's menu depend on the common
CPU_MITIGATIONS. This allows keeping a single point of contact for all
of x86's mitigations, and it's not clear that other architectures *want*
to allow disabling mitigations at compile-time.
Fixes: f337a6a21e ("x86/cpu: Actually turn off mitigations by default for SPECULATION_MITIGATIONS=n")
Closes: https://lkml.kernel.org/r/20240413115324.53303a68%40canb.auug.org.au
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
Acked-by: Borislav Petkov (AMD) <bp@alien8.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240420000556.2645001-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit b5085b5ac1 which is
commit 0958b33ef5 upstream.
The change has an incorrect assumption about the return value because
in the current stable trees for versions 5.15 and before, the following
commit responsible for making 0 a success value is not present:
b8cc44a4d3 ("tracing: Remove logic for registering multiple event triggers at a time")
The return value should be 0 on failure in the current tree, because in
the functions event_trigger_callback() and event_enable_trigger_func(),
we have:
ret = cmd_ops->reg(glob, trigger_ops, trigger_data, file);
/*
* The above returns on success the # of functions enabled,
* but if it didn't find any functions it returns zero.
* Consider no functions a failure too.
*/
if (!ret) {
ret = -ENOENT;
Cc: stable@kernel.org # 5.15, 5.10, 5.4, 4.19
Signed-off-by: Siddh Raman Pant <siddh.raman.pant@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 325f3fb551 upstream.
When unloading a module, its state is changing MODULE_STATE_LIVE ->
MODULE_STATE_GOING -> MODULE_STATE_UNFORMED. Each change will take
a time. `is_module_text_address()` and `__module_text_address()`
works with MODULE_STATE_LIVE and MODULE_STATE_GOING.
If we use `is_module_text_address()` and `__module_text_address()`
separately, there is a chance that the first one is succeeded but the
next one is failed because module->state becomes MODULE_STATE_UNFORMED
between those operations.
In `check_kprobe_address_safe()`, if the second `__module_text_address()`
is failed, that is ignored because it expected a kernel_text address.
But it may have failed simply because module->state has been changed
to MODULE_STATE_UNFORMED. In this case, arm_kprobe() will try to modify
non-exist module text address (use-after-free).
To fix this problem, we should not use separated `is_module_text_address()`
and `__module_text_address()`, but use only `__module_text_address()`
once and do `try_module_get(module)` which is only available with
MODULE_STATE_LIVE.
Link: https://lore.kernel.org/all/20240410015802.265220-1-zhengyejian1@huawei.com/
Fixes: 28f6c37a29 ("kprobes: Forbid probing on trampoline and BPF code areas")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
[Fix conflict due to lack dependency
commit 223a76b268 ("kprobes: Fix coding style issues")]
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a672b2e36a upstream.
The bpf_ringbuf_submit() and bpf_ringbuf_discard() have ARG_PTR_TO_ALLOC_MEM
in their bpf_func_proto definition as their first argument, and thus both expect
the result from a prior bpf_ringbuf_reserve() call which has a return type of
RET_PTR_TO_ALLOC_MEM_OR_NULL.
While the non-NULL memory from bpf_ringbuf_reserve() can be passed to other
helpers, the two sinks (bpf_ringbuf_submit(), bpf_ringbuf_discard()) right now
only enforce a register type of PTR_TO_MEM.
This can lead to potential type confusion since it would allow other PTR_TO_MEM
memory to be passed into the two sinks which did not come from bpf_ringbuf_reserve().
Add a new MEM_ALLOC composable type attribute for PTR_TO_MEM, and enforce that:
- bpf_ringbuf_reserve() returns NULL or PTR_TO_MEM | MEM_ALLOC
- bpf_ringbuf_submit() and bpf_ringbuf_discard() only take PTR_TO_MEM | MEM_ALLOC
but not plain PTR_TO_MEM arguments via ARG_PTR_TO_ALLOC_MEM
- however, other helpers might treat PTR_TO_MEM | MEM_ALLOC as plain PTR_TO_MEM
to populate the memory area when they use ARG_PTR_TO_{UNINIT_,}MEM in their
func proto description
Fixes: 457f44363a ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Edward Liaw <edliaw@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 64620e0a1e upstream.
Both bpf_ringbuf_submit() and bpf_ringbuf_discard() have ARG_PTR_TO_ALLOC_MEM
in their bpf_func_proto definition as their first argument. They both expect
the result from a prior bpf_ringbuf_reserve() call which has a return type of
RET_PTR_TO_ALLOC_MEM_OR_NULL.
Meaning, after a NULL check in the code, the verifier will promote the register
type in the non-NULL branch to a PTR_TO_MEM and in the NULL branch to a known
zero scalar. Generally, pointer arithmetic on PTR_TO_MEM is allowed, so the
latter could have an offset.
The ARG_PTR_TO_ALLOC_MEM expects a PTR_TO_MEM register type. However, the non-
zero result from bpf_ringbuf_reserve() must be fed into either bpf_ringbuf_submit()
or bpf_ringbuf_discard() but with the original offset given it will then read
out the struct bpf_ringbuf_hdr mapping.
The verifier missed to enforce a zero offset, so that out of bounds access
can be triggered which could be used to escalate privileges if unprivileged
BPF was enabled (disabled by default in kernel).
Fixes: 457f44363a ("bpf: Implement BPF ring buffer and verifier support for it")
Reported-by: <tr3e.wang@gmail.com> (SecCoder Security Lab)
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Edward Liaw <edliaw@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6788ab2350 upstream.
Right now the assertion on check_ptr_off_reg() is only enforced for register
types PTR_TO_CTX (and open coded also for PTR_TO_BTF_ID), however, this is
insufficient since many other PTR_TO_* register types such as PTR_TO_FUNC do
not handle/expect register offsets when passed to helper functions.
Given this can slip-through easily when adding new types, make this an explicit
allow-list and reject all other current and future types by default if this is
encountered.
Also, extend check_ptr_off_reg() to handle PTR_TO_BTF_ID as well instead of
duplicating it. For PTR_TO_BTF_ID, reg->off is used for BTF to match expected
BTF ids if struct offset is used. This part still needs to be allowed, but the
dynamic off from the tnum must be rejected.
Fixes: 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper")
Fixes: eaa6bcb71e ("bpf: Introduce bpf_per_cpu_ptr()")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Edward Liaw <edliaw@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit be80a1d3f9 upstream.
Generalize the check_ctx_reg() helper function into a more generic named one
so that it can be reused for other register types as well to check whether
their offset is non-zero. No functional change.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Edward Liaw <edliaw@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3363bd0cfb upstream.
Allow passing PTR_TO_CTX, if the kfunc expects a matching struct type,
and punt to PTR_TO_MEM block if reg->type does not fall in one of
PTR_TO_BTF_ID or PTR_TO_SOCK* types. This will be used by future commits
to get access to XDP and TC PTR_TO_CTX, and pass various data (flags,
l4proto, netns_id, etc.) encoded in opts struct passed as pointer to
kfunc.
For PTR_TO_MEM support, arguments are currently limited to pointer to
scalar, or pointer to struct composed of scalars. This is done so that
unsafe scenarios (like passing PTR_TO_MEM where PTR_TO_BTF_ID of
in-kernel valid structure is expected, which may have pointers) are
avoided. Since the argument checking happens basd on argument register
type, it is not easy to ascertain what the expected type is. In the
future, support for PTR_TO_MEM for kfunc can be extended to serve other
usecases. The struct type whose pointer is passed in may have maximum
nesting depth of 4, all recursively composed of scalars or struct with
scalars.
Future commits will add negative tests that check whether these
restrictions imposed for kfunc arguments are duly rejected by BPF
verifier or not.
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211217015031.1278167-4-memxor@gmail.com
Signed-off-by: Edward Liaw <edliaw@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit f337a6a21e upstream.
Initialize cpu_mitigations to CPU_MITIGATIONS_OFF if the kernel is built
with CONFIG_SPECULATION_MITIGATIONS=n, as the help text quite clearly
states that disabling SPECULATION_MITIGATIONS is supposed to turn off all
mitigations by default.
│ If you say N, all mitigations will be disabled. You really
│ should know what you are doing to say so.
As is, the kernel still defaults to CPU_MITIGATIONS_AUTO, which results in
some mitigations being enabled in spite of SPECULATION_MITIGATIONS=n.
Fixes: f43b9876e8 ("x86/retbleed: Add fine grained Kconfig knobs")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/20240409175108.1512861-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit ffe3986fec upstream.
The "buffer_percent" logic that is used by the ring buffer splice code to
only wake up the tasks when there's no data after the buffer is filled to
the percentage of the "buffer_percent" file is dependent on three
variables that determine the amount of data that is in the ring buffer:
1) pages_read - incremented whenever a new sub-buffer is consumed
2) pages_lost - incremented every time a writer overwrites a sub-buffer
3) pages_touched - incremented when a write goes to a new sub-buffer
The percentage is the calculation of:
(pages_touched - (pages_lost + pages_read)) / nr_pages
Basically, the amount of data is the total number of sub-bufs that have been
touched, minus the number of sub-bufs lost and sub-bufs consumed. This is
divided by the total count to give the buffer percentage. When the
percentage is greater than the value in the "buffer_percent" file, it
wakes up splice readers waiting for that amount.
It was observed that over time, the amount read from the splice was
constantly decreasing the longer the trace was running. That is, if one
asked for 60%, it would read over 60% when it first starts tracing, but
then it would be woken up at under 60% and would slowly decrease the
amount of data read after being woken up, where the amount becomes much
less than the buffer percent.
This was due to an accounting of the pages_touched incrementation. This
value is incremented whenever a writer transfers to a new sub-buffer. But
the place where it was incremented was incorrect. If a writer overflowed
the current sub-buffer it would go to the next one. If it gets preempted
by an interrupt at that time, and the interrupt performs a trace, it too
will end up going to the next sub-buffer. But only one should increment
the counter. Unfortunately, that was not the case.
Change the cmpxchg() that does the real switch of the tail-page into a
try_cmpxchg(), and on success, perform the increment of pages_touched. This
will only increment the counter once for when the writer moves to a new
sub-buffer, and not when there's a race and is incremented for when a
writer and its preempting writer both move to the same new sub-buffer.
Link: https://lore.kernel.org/linux-trace-kernel/20240409151309.0d0e5056@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 2c2b0a78b3 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit d988d9a9b9 ]
If the kernel crashes in a context where printk() calls always
defer printing (such as in NMI or inside a printk_safe section)
then the final panic messages will be deferred to irq_work. But
if irq_work is not available, the messages will not get printed
unless explicitly flushed. The result is that the final
"end Kernel panic" banner does not get printed.
Add one final flush after the last printk() call to make sure
the final panic messages make it out as well.
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20240207134103.1357162-14-john.ogness@linutronix.de
Signed-off-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 48dfb5d256 upstream.
Make the region inside the rwsem_write_trylock non preemptible.
We observe RT task is hogging CPU when trying to acquire rwsem lock
which was acquired by a kworker task but before the rwsem owner was set.
Here is the scenario:
1. CFS task (affined to a particular CPU) takes rwsem lock.
2. CFS task gets preempted by a RT task before setting owner.
3. RT task (FIFO) is trying to acquire the lock, but spinning until
RT throttling happens for the lock as the lock was taken by CFS task.
This patch attempts to fix the above issue by disabling preemption
until owner is set for the lock. While at it also fix the issues
at the places where rwsem_{set,clear}_owner() are called.
This also adds lockdep annotation of preemption disable in
rwsem_{set,clear}_owner() on Peter Z. suggestion.
Signed-off-by: Gokul krishna Krishnakumar <quic_gokukris@quicinc.com>
Signed-off-by: Mukesh Ojha <quic_mojha@quicinc.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Waiman Long <longman@redhat.com>
Link: https://lore.kernel.org/r/1662661467-24203-1-git-send-email-quic_mojha@quicinc.com
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 6b959ba22d upstream.
perf_output_read_group may respond to IPI request of other cores and invoke
__perf_install_in_context function. As a result, hwc configuration is modified.
causing inconsistency and unexpected consequences.
Interrupts are not disabled when perf_output_read_group reads PMU counter.
In this case, IPI request may be received from other cores.
As a result, PMU configuration is modified and an error occurs when
reading PMU counter:
CPU0 CPU1
__se_sys_perf_event_open
perf_install_in_context
perf_output_read_group smp_call_function_single
for_each_sibling_event(sub, leader) { generic_exec_single
if ((sub != event) && remote_function
(sub->state == PERF_EVENT_STATE_ACTIVE)) |
<enter IPI handler: __perf_install_in_context> <----RAISE IPI-----+
__perf_install_in_context
ctx_resched
event_sched_out
armpmu_del
...
hwc->idx = -1; // event->hwc.idx is set to -1
...
<exit IPI>
sub->pmu->read(sub);
armpmu_read
armv8pmu_read_counter
armv8pmu_read_hw_counter
int idx = event->hw.idx; // idx = -1
u64 val = armv8pmu_read_evcntr(idx);
u32 counter = ARMV8_IDX_TO_COUNTER(idx); // invalid counter = 30
read_pmevcntrn(counter) // undefined instruction
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20220902082918.179248-1-yangjihong1@huawei.com
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit f3010343d9 ]
Instead of passing the allow_dups argument to fsnotify_add_mark()
as an argument, define the group flag FSNOTIFY_GROUP_DUPS to express
the allow_dups behavior and set this behavior at group creation time
for all calls of fsnotify_add_mark().
Rename the allow_dups argument to generic add_flags argument for future
use.
Link: https://lore.kernel.org/r/20220422120327.3459282-6-amir73il@gmail.com
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit 867a448d58 ]
Add flags argument to fsnotify_alloc_group(), define and use the flag
FSNOTIFY_GROUP_USER in inotify and fanotify instead of the helper
fsnotify_alloc_user_group() to indicate user allocation.
Although the flag FSNOTIFY_GROUP_USER is currently not used after group
allocation, we store the flags argument in the group struct for future
use of other group flags.
Link: https://lore.kernel.org/r/20220422120327.3459282-5-amir73il@gmail.com
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit f49169c97f ]
struct svc_serv_ops is about to be removed.
Neil Brown says:
> I suspect svo_module can go as well - I don't think the thread is
> ever the thing that primarily keeps a module active.
A random sample of kthread_create() callers shows sunrpc is the only
one that manages module reference count in this way.
Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit ca3574bd65 ]
Update module_put_and_exit to call kthread_exit instead of do_exit.
Change the name to reflect this change in functionality. All of the
users of module_put_and_exit are causing the current kthread to exit
so this change makes it clear what is happening. There is no
functional change.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit bbda86e988 ]
The way the per task_struct exit_code is used by kernel threads is not
quite compatible how it is used by userspace applications. The low
byte of the userspace exit_code value encodes the exit signal. While
kthreads just use the value as an int holding ordinary kernel function
exit status like -EPERM.
Add kthread_exit to clearly separate the two kinds of uses.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Stable-dep-of: ca3574bd65 ("exit: Rename module_put_and_exit to module_put_and_kthread_exit")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Upstream commit a229cc14f3 ]
Streaming DMA mapping involving an IOMMU may be much slower for larger
total mapping size. This is because every IOMMU DMA mapping requires an
IOVA to be allocated and freed. IOVA sizes above a certain limit are not
cached, which can have a big impact on DMA mapping performance.
Provide an API for device drivers to know this "optimal" limit, such that
they may try to produce mapping which don't exceed it.
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Stable-dep-of: afc5aa46ed ("iommu/dma: Force swiotlb_max_mapping_size on an untrusted device")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 51b30ecb73 ]
Nicolin reports that swiotlb buffer allocations fail for an NVME device
behind an IOMMU using 64KiB pages. This is because we end up with a
minimum allocation alignment of 64KiB (for the IOMMU to map the buffer
safely) but a minimum DMA alignment mask corresponding to a 4KiB NVME
page (i.e. preserving the 4KiB page offset from the original allocation).
If the original address is not 4KiB-aligned, the allocation will fail
because swiotlb_search_pool_area() erroneously compares these unmasked
bits with the 64KiB-aligned candidate allocation.
Tweak swiotlb_search_pool_area() so that the DMA alignment mask is
reduced based on the required alignment of the allocation.
Fixes: 82612d66d5 ("iommu: Allow the dma-iommu api to use bounce buffers")
Link: https://lore.kernel.org/r/cover.1707851466.git.nicolinc@nvidia.com
Reported-by: Nicolin Chen <nicolinc@nvidia.com>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit fb13b11d53 ]
When a probe is registered at the trace_sys_enter() tracepoint, and that
probe changes the system call number, the old system call still gets
executed. This worked correctly until commit b6ec413461 ("core/entry:
Report syscall correctly for trace and audit"), which removed the
re-evaluation of the syscall number after the trace point.
Restore the original semantics by re-evaluating the system call number
after trace_sys_enter().
The performance impact of this re-evaluation is minimal because it only
takes place when a trace point is active, and compared to the actual trace
point overhead the read from a cache hot variable is negligible.
Fixes: b6ec413461 ("core/entry: Report syscall correctly for trace and audit")
Signed-off-by: André Rösti <an.roesti@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20240311211704.7262-1-an.roesti@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit e5d7c19165 upstream.
The .release() function does not get called until all readers of a file
descriptor are finished.
If a thread is blocked on reading a file descriptor in ring_buffer_wait(),
and another thread closes the file descriptor, it will not wake up the
other thread as ring_buffer_wake_waiters() is called by .release(), and
that will not get called until the .read() is finished.
The issue originally showed up in trace-cmd, but the readers are actually
other processes with their own file descriptors. So calling close() would wake
up the other tasks because they are blocked on another descriptor then the
one that was closed(). But there's other wake ups that solve that issue.
When a thread is blocked on a read, it can still hang even when another
thread closed its descriptor.
This is what the .flush() callback is for. Have the .flush() wake up the
readers.
Link: https://lore.kernel.org/linux-trace-kernel/20240308202432.107909457@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: f3ddb74ad0 ("tracing: Wake up ring buffer waiters on closing of the file")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 8145f1c35f ]
If a reader of the ring buffer is doing a poll, and waiting for the ring
buffer to hit a specific watermark, there could be a case where it gets
into an infinite ping-pong loop.
The poll code has:
rbwork->full_waiters_pending = true;
if (!cpu_buffer->shortest_full ||
cpu_buffer->shortest_full > full)
cpu_buffer->shortest_full = full;
The writer will see full_waiters_pending and check if the ring buffer is
filled over the percentage of the shortest_full value. If it is, it calls
an irq_work to wake up all the waiters.
But the code could get into a circular loop:
CPU 0 CPU 1
----- -----
[ Poll ]
[ shortest_full = 0 ]
rbwork->full_waiters_pending = true;
if (rbwork->full_waiters_pending &&
[ buffer percent ] > shortest_full) {
rbwork->wakeup_full = true;
[ queue_irqwork ]
cpu_buffer->shortest_full = full;
[ IRQ work ]
if (rbwork->wakeup_full) {
cpu_buffer->shortest_full = 0;
wakeup poll waiters;
[woken]
if ([ buffer percent ] > full)
break;
rbwork->full_waiters_pending = true;
if (rbwork->full_waiters_pending &&
[ buffer percent ] > shortest_full) {
rbwork->wakeup_full = true;
[ queue_irqwork ]
cpu_buffer->shortest_full = full;
[ IRQ work ]
if (rbwork->wakeup_full) {
cpu_buffer->shortest_full = 0;
wakeup poll waiters;
[woken]
[ Wash, rinse, repeat! ]
In the poll, the shortest_full needs to be set before the
full_pending_waiters, as once that is set, the writer will compare the
current shortest_full (which is incorrect) to decide to call the irq_work,
which will reset the shortest_full (expecting the readers to update it).
Also move the setting of full_waiters_pending after the check if the ring
buffer has the required percentage filled. There's no reason to tell the
writer to wake up waiters if there are no waiters.
Link: https://lore.kernel.org/linux-trace-kernel/20240312131952.630922155@goodmis.org
Cc: stable@vger.kernel.org
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 68282dd930 ]
The "shortest_full" variable is used to keep track of the waiter that is
waiting for the smallest amount on the ring buffer before being woken up.
When a tasks waits on the ring buffer, it passes in a "full" value that is
a percentage. 0 means wake up on any data. 1-100 means wake up from 1% to
100% full buffer.
As all waiters are on the same wait queue, the wake up happens for the
waiter with the smallest percentage.
The problem is that the smallest_full on the cpu_buffer that stores the
smallest amount doesn't get reset when all the waiters are woken up. It
does get reset when the ring buffer is reset (echo > /sys/kernel/tracing/trace).
This means that tasks may be woken up more often then when they want to
be. Instead, have the shortest_full field get reset just before waking up
all the tasks. If the tasks wait again, they will update the shortest_full
before sleeping.
Also add locking around setting of shortest_full in the poll logic, and
change "work" to "rbwork" to match the variable name for rb_irq_work
structures that are used in other places.
Link: https://lore.kernel.org/linux-trace-kernel/20240308202431.948914369@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: 2c2b0a78b3 ("ring-buffer: Add percentage of ring buffer full to wake up reader")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 8145f1c35f ("ring-buffer: Fix full_waiters_pending in poll")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 761d9473e2 ]
The rb_watermark_hit() checks if the amount of data in the ring buffer is
above the percentage level passed in by the "full" variable. If it is, it
returns true.
But it also sets the "shortest_full" field of the cpu_buffer that informs
writers that it needs to call the irq_work if the amount of data on the
ring buffer is above the requested amount.
The rb_watermark_hit() always sets the shortest_full even if the amount in
the ring buffer is what it wants. As it is not going to wait, because it
has what it wants, there's no reason to set shortest_full.
Link: https://lore.kernel.org/linux-trace-kernel/20240312115641.6aa8ba08@gandalf.local.home
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Fixes: 42fb0a1e84 ("tracing/ring-buffer: Have polling block on watermark")
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit b359457368 ]
A task can wait on a ring buffer for when it fills up to a specific
watermark. The writer will check the minimum watermark that waiters are
waiting for and if the ring buffer is past that, it will wake up all the
waiters.
The waiters are in a wait loop, and will first check if a signal is
pending and then check if the ring buffer is at the desired level where it
should break out of the loop.
If a file that uses a ring buffer closes, and there's threads waiting on
the ring buffer, it needs to wake up those threads. To do this, a
"wait_index" was used.
Before entering the wait loop, the waiter will read the wait_index. On
wakeup, it will check if the wait_index is different than when it entered
the loop, and will exit the loop if it is. The waker will only need to
update the wait_index before waking up the waiters.
This had a couple of bugs. One trivial one and one broken by design.
The trivial bug was that the waiter checked the wait_index after the
schedule() call. It had to be checked between the prepare_to_wait() and
the schedule() which it was not.
The main bug is that the first check to set the default wait_index will
always be outside the prepare_to_wait() and the schedule(). That's because
the ring_buffer_wait() doesn't have enough context to know if it should
break out of the loop.
The loop itself is not needed, because all the callers to the
ring_buffer_wait() also has their own loop, as the callers have a better
sense of what the context is to decide whether to break out of the loop
or not.
Just have the ring_buffer_wait() block once, and if it gets woken up, exit
the function and let the callers decide what to do next.
Link: https://lore.kernel.org/all/CAHk-=whs5MdtNjzFkTyaUy=vHi=qwWgPi0JgTe6OYUYMNSRZfg@mail.gmail.com/
Link: https://lore.kernel.org/linux-trace-kernel/20240308202431.792933613@goodmis.org
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linke li <lilinke99@qq.com>
Cc: Rabin Vincent <rabin@rab.in>
Fixes: e30f53aad2 ("tracing: Do not busy wait in buffer splice")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 761d9473e2 ("ring-buffer: Do not set shortest_full when full target is hit")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 801410b26a ]
During the handoff from earlycon to the real console driver, we have
two separate drivers operating on the same device concurrently. In the
case of the 8250 driver these concurrent accesses cause problems due
to the driver's use of banked registers, controlled by LCR.DLAB. It is
possible for the setup(), config_port(), pm() and set_mctrl() callbacks
to set DLAB, which can cause the earlycon code that intends to access
TX to instead access DLL, leading to missed output and corruption on
the serial line due to unintended modifications to the baud rate.
In particular, for setup() we have:
univ8250_console_setup()
-> serial8250_console_setup()
-> uart_set_options()
-> serial8250_set_termios()
-> serial8250_do_set_termios()
-> serial8250_do_set_divisor()
For config_port() we have:
serial8250_config_port()
-> autoconfig()
For pm() we have:
serial8250_pm()
-> serial8250_do_pm()
-> serial8250_set_sleep()
For set_mctrl() we have (for some devices):
serial8250_set_mctrl()
-> omap8250_set_mctrl()
-> __omap8250_set_mctrl()
To avoid such problems, let's make it so that the console is locked
during pre-registration calls to these callbacks, which will prevent
the earlycon driver from running concurrently.
Remove the partial solution to this problem in the 8250 driver
that locked the console only during autoconfig_irq(), as this would
result in a deadlock with the new approach. The console continues
to be locked during autoconfig_irq() because it can only be called
through uart_configure_port().
Although this patch introduces more locking than strictly necessary
(and in particular it also locks during the call to rs485_config()
which is not affected by this issue as far as I can tell), it follows
the principle that it is the responsibility of the generic console
code to manage the earlycon handoff by ensuring that earlycon and real
console driver code cannot run concurrently, and not the individual
drivers.
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: John Ogness <john.ogness@linutronix.de>
Link: https://linux-review.googlesource.com/id/I7cf8124dcebf8618e6b2ee543fa5b25532de55d8
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240304214350.501253-1-pcc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit ed758b30d5 ]
Put the code enabling a console by default into a separate function
called try_enable_default_console().
Rename try_enable_new_console() to try_enable_preferred_console() to
make the purpose of the different variants more clear.
It is a code refactoring without any functional change.
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Link: https://lore.kernel.org/r/20211122132649.12737-2-pmladek@suse.com
Stable-dep-of: 801410b26a ("serial: Lock console when calling into driver before registration")
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 9bc4ffd32e ]
psci_init_system_suspend() invokes suspend_set_ops() very early during
bootup even before kernel command line for mem_sleep_default is setup.
This leads to kernel command line mem_sleep_default=s2idle not working
as mem_sleep_current gets changed to deep via suspend_set_ops() and never
changes back to s2idle.
Set mem_sleep_current along with mem_sleep_default during kernel command
line setup as default suspend mode.
Fixes: faf7ec4a92 ("drivers: firmware: psci: add system suspend support")
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: Maulik Shah <quic_mkshah@quicinc.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Jakub Sitnicki