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2025-09-14Merge tag 'timers-urgent-2025-09-14' of ↵Linus Torvalds1-8/+3
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Ingo Molnar: "Fix a lost-timeout CPU hotplug bug in the hrtimer code, which can trigger with certain hardware configs and regular HZ" * tag 'timers-urgent-2025-09-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: hrtimers: Unconditionally update target CPU base after offline timer migration
2025-09-11Merge tag 'pm-6.17-rc6' of ↵Linus Torvalds2-4/+26
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management fixes from Rafael Wysocki: "These fix a nasty hibernation regression introduced during the 6.16 cycle, an issue related to energy model management occurring on Intel hybrid systems where some CPUs are offline to start with, and two regressions in the amd-pstate driver: - Restore a pm_restrict_gfp_mask() call in hibernation_snapshot() that was removed incorrectly during the 6.16 development cycle (Rafael Wysocki) - Introduce a function for registering a perf domain without triggering a system-wide CPU capacity update and make the intel_pstate driver use it to avoid reocurring unsuccessful attempts to update capacities of all CPUs in the system (Rafael Wysocki) - Fix setting of CPPC.min_perf in the active mode with performance governor in the amd-pstate driver to restore its expected behavior changed recently (Gautham Shenoy) - Avoid mistakenly setting EPP to 0 in the amd-pstate driver after system resume as a result of recent code changes (Mario Limonciello)" * tag 'pm-6.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: PM: hibernate: Restrict GFP mask in hibernation_snapshot() PM: EM: Add function for registering a PD without capacity update cpufreq/amd-pstate: Fix a regression leading to EPP 0 after resume cpufreq/amd-pstate: Fix setting of CPPC.min_perf in active mode for performance governor
2025-09-11Merge tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfLinus Torvalds7-16/+36
Pull bpf fixes from Alexei Starovoitov: "A number of fixes accumulated due to summer vacations - Fix out-of-bounds dynptr write in bpf_crypto_crypt() kfunc which was misidentified as a security issue (Daniel Borkmann) - Update the list of BPF selftests maintainers (Eduard Zingerman) - Fix selftests warnings with icecc compiler (Ilya Leoshkevich) - Disable XDP/cpumap direct return optimization (Jesper Dangaard Brouer) - Fix unexpected get_helper_proto() result in unusual configuration BPF_SYSCALL=y and BPF_EVENTS=n (Jiri Olsa) - Allow fallback to interpreter when JIT support is limited (KaFai Wan) - Fix rqspinlock and choose trylock fallback for NMI waiters. Pick the simplest fix. More involved fix is targeted bpf-next (Kumar Kartikeya Dwivedi) - Fix cleanup when tcp_bpf_send_verdict() fails to allocate psock->cork (Kuniyuki Iwashima) - Disallow bpf_timer in PREEMPT_RT for now. Proper solution is being discussed for bpf-next. (Leon Hwang) - Fix XSK cq descriptor production (Maciej Fijalkowski) - Tell memcg to use allow_spinning=false path in bpf_timer_init() to avoid lockup in cgroup_file_notify() (Peilin Ye) - Fix bpf_strnstr() to handle suffix match cases (Rong Tao)" * tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: selftests/bpf: Skip timer cases when bpf_timer is not supported bpf: Reject bpf_timer for PREEMPT_RT tcp_bpf: Call sk_msg_free() when tcp_bpf_send_verdict() fails to allocate psock->cork. bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init() bpf: Allow fall back to interpreter for programs with stack size <= 512 rqspinlock: Choose trylock fallback for NMI waiters xsk: Fix immature cq descriptor production bpf: Update the list of BPF selftests maintainers selftests/bpf: Add tests for bpf_strnstr selftests/bpf: Fix "expression result unused" warnings with icecc bpf: Fix bpf_strnstr() to handle suffix match cases better selftests/bpf: Extend crypto_sanity selftest with invalid dst buffer bpf: Fix out-of-bounds dynptr write in bpf_crypto_crypt bpf: Check the helper function is valid in get_helper_proto bpf, cpumap: Disable page_pool direct xdp_return need larger scope
2025-09-11Merge branches 'pm-sleep' and 'pm-em'Rafael J. Wysocki2-4/+26
Merge a hibernation regression fix and an fix related to energy model management for 6.17-rc6 * pm-sleep: PM: hibernate: Restrict GFP mask in hibernation_snapshot() * pm-em: PM: EM: Add function for registering a PD without capacity update
2025-09-10bpf: Reject bpf_timer for PREEMPT_RTLeon Hwang1-0/+4
When enable CONFIG_PREEMPT_RT, the kernel will warn when run timer selftests by './test_progs -t timer': BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48 In order to avoid such warning, reject bpf_timer in verifier when PREEMPT_RT is enabled. Signed-off-by: Leon Hwang <leon.hwang@linux.dev> Link: https://lore.kernel.org/r/20250910125740.52172-2-leon.hwang@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-10Merge tag 'trace-v6.17-rc4' of ↵Linus Torvalds4-5/+13
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Remove redundant __GFP_NOWARN flag is kmalloc As now __GFP_NOWARN is part of __GFP_NOWAIT, it can be removed from kmalloc as it is redundant. - Use copy_from_user_nofault() instead of _inatomic() for trace markers The trace_marker files are written to to allow user space to quickly write into the tracing ring buffer. Back in 2016, the get_user_pages_fast() and the kmap() logic was replaced by a __copy_from_user_inatomic(), but didn't properly disable page faults around it. Since the time this was added, copy_from_user_nofault() was added which does the required page fault disabling for us. - Fix the assembly markup in the ftrace direct sample code The ftrace direct sample code (which is also used for selftests), had the size directive between the "leave" and the "ret" instead of after the ret. This caused objtool to think the code was unreachable. - Only call unregister_pm_notifier() on outer most fgraph registration There was an error path in register_ftrace_graph() that did not call unregister_pm_notifier() on error, so it was added in the error path. The problem with that fix, is that register_pm_notifier() is only called by the initial user of fgraph. If that succeeds, but another fgraph registration were to fail, then unregister_pm_notifier() would be called incorrectly. - Fix a crash in osnoise when zero size cpumask is passed in If a zero size CPU mask is passed in, the kmalloc() would return ZERO_SIZE_PTR which is not checked, and the code would continue thinking it had real memory and crash. If zero is passed in as the size of the write, simply return 0. - Fix possible warning in trace_pid_write() If while processing a series of numbers passed to the "set_event_pid" file, and one of the updates fails to allocate (triggered by a fault injection), it can cause a warning to trigger. Check the return value of the call to trace_pid_list_set() and break out early with an error code if it fails. * tag 'trace-v6.17-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: tracing: Silence warning when chunk allocation fails in trace_pid_write tracing/osnoise: Fix null-ptr-deref in bitmap_parselist() trace/fgraph: Fix error handling ftrace/samples: Fix function size computation tracing: Fix tracing_marker may trigger page fault during preempt_disable trace: Remove redundant __GFP_NOWARN
2025-09-10PM: hibernate: Restrict GFP mask in hibernation_snapshot()Rafael J. Wysocki1-0/+1
Commit 12ffc3b1513e ("PM: Restrict swap use to later in the suspend sequence") incorrectly removed a pm_restrict_gfp_mask() call from hibernation_snapshot(), so memory allocations involving swap are not prevented from being carried out in this code path any more which may lead to serious breakage. The symptoms of such breakage have become visible after adding a shrink_shmem_memory() call to hibernation_snapshot() in commit 2640e819474f ("PM: hibernate: shrink shmem pages after dev_pm_ops.prepare()") which caused this problem to be much more likely to manifest itself. However, since commit 2640e819474f was initially present in the DRM tree that did not include commit 12ffc3b1513e, the symptoms of this issue were not visible until merge commit 260f6f4fda93 ("Merge tag 'drm-next-2025-07-30' of https://gitlab.freedesktop.org/drm/kernel") that exposed it through an entirely reasonable merge conflict resolution. Fixes: 12ffc3b1513e ("PM: Restrict swap use to later in the suspend sequence") Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220555 Reported-by: Todd Brandt <todd.e.brandt@linux.intel.com> Tested-by: Todd Brandt <todd.e.brandt@linux.intel.com> Cc: 6.16+ <stable@vger.kernel.org> # 6.16+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
2025-09-10PM: EM: Add function for registering a PD without capacity updateRafael J. Wysocki1-4/+25
The intel_pstate driver manages CPU capacity changes itself and it does not need an update of the capacity of all CPUs in the system to be carried out after registering a PD. Moreover, in some configurations (for instance, an SMT-capable hybrid x86 system booted with nosmt in the kernel command line) the em_check_capacity_update() call at the end of em_dev_register_perf_domain() always fails and reschedules itself to run once again in 1 s, so effectively it runs in vain every 1 s forever. To address this, introduce a new variant of em_dev_register_perf_domain(), called em_dev_register_pd_no_update(), that does not invoke em_check_capacity_update(), and make intel_pstate use it instead of the original. Fixes: 7b010f9b9061 ("cpufreq: intel_pstate: EAS support for hybrid platforms") Closes: https://lore.kernel.org/linux-pm/40212796-734c-4140-8a85-854f72b8144d@panix.com/ Reported-by: Kenneth R. Crudup <kenny@panix.com> Tested-by: Kenneth R. Crudup <kenny@panix.com> Cc: 6.16+ <stable@vger.kernel.org> # 6.16+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2025-09-09bpf: Tell memcg to use allow_spinning=false path in bpf_timer_init()Peilin Ye1-2/+5
Currently, calling bpf_map_kmalloc_node() from __bpf_async_init() can cause various locking issues; see the following stack trace (edited for style) as one example: ... [10.011566] do_raw_spin_lock.cold [10.011570] try_to_wake_up (5) double-acquiring the same [10.011575] kick_pool rq_lock, causing a hardlockup [10.011579] __queue_work [10.011582] queue_work_on [10.011585] kernfs_notify [10.011589] cgroup_file_notify [10.011593] try_charge_memcg (4) memcg accounting raises an [10.011597] obj_cgroup_charge_pages MEMCG_MAX event [10.011599] obj_cgroup_charge_account [10.011600] __memcg_slab_post_alloc_hook [10.011603] __kmalloc_node_noprof ... [10.011611] bpf_map_kmalloc_node [10.011612] __bpf_async_init [10.011615] bpf_timer_init (3) BPF calls bpf_timer_init() [10.011617] bpf_prog_xxxxxxxxxxxxxxxx_fcg_runnable [10.011619] bpf__sched_ext_ops_runnable [10.011620] enqueue_task_scx (2) BPF runs with rq_lock held [10.011622] enqueue_task [10.011626] ttwu_do_activate [10.011629] sched_ttwu_pending (1) grabs rq_lock ... The above was reproduced on bpf-next (b338cf849ec8) by modifying ./tools/sched_ext/scx_flatcg.bpf.c to call bpf_timer_init() during ops.runnable(), and hacking the memcg accounting code a bit to make a bpf_timer_init() call more likely to raise an MEMCG_MAX event. We have also run into other similar variants (both internally and on bpf-next), including double-acquiring cgroup_file_kn_lock, the same worker_pool::lock, etc. As suggested by Shakeel, fix this by using __GFP_HIGH instead of GFP_ATOMIC in __bpf_async_init(), so that e.g. if try_charge_memcg() raises an MEMCG_MAX event, we call __memcg_memory_event() with @allow_spinning=false and avoid calling cgroup_file_notify() there. Depends on mm patch "memcg: skip cgroup_file_notify if spinning is not allowed": https://lore.kernel.org/bpf/20250905201606.66198-1-shakeel.butt@linux.dev/ v0 approach s/bpf_map_kmalloc_node/bpf_mem_alloc/ https://lore.kernel.org/bpf/20250905061919.439648-1-yepeilin@google.com/ v1 approach: https://lore.kernel.org/bpf/20250905234547.862249-1-yepeilin@google.com/ Fixes: b00628b1c7d5 ("bpf: Introduce bpf timers.") Suggested-by: Shakeel Butt <shakeel.butt@linux.dev> Signed-off-by: Peilin Ye <yepeilin@google.com> Link: https://lore.kernel.org/r/20250909095222.2121438-1-yepeilin@google.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-09bpf: Allow fall back to interpreter for programs with stack size <= 512KaFai Wan1-7/+9
OpenWRT users reported regression on ARMv6 devices after updating to latest HEAD, where tcpdump filter: tcpdump "not ether host 3c37121a2b3c and not ether host 184ecbca2a3a \ and not ether host 14130b4d3f47 and not ether host f0f61cf440b7 \ and not ether host a84b4dedf471 and not ether host d022be17e1d7 \ and not ether host 5c497967208b and not ether host 706655784d5b" fails with warning: "Kernel filter failed: No error information" when using config: # CONFIG_BPF_JIT_ALWAYS_ON is not set CONFIG_BPF_JIT_DEFAULT_ON=y The issue arises because commits: 1. "bpf: Fix array bounds error with may_goto" changed default runtime to __bpf_prog_ret0_warn when jit_requested = 1 2. "bpf: Avoid __bpf_prog_ret0_warn when jit fails" returns error when jit_requested = 1 but jit fails This change restores interpreter fallback capability for BPF programs with stack size <= 512 bytes when jit fails. Reported-by: Felix Fietkau <nbd@nbd.name> Closes: https://lore.kernel.org/bpf/2e267b4b-0540-45d8-9310-e127bf95fc63@nbd.name/ Fixes: 6ebc5030e0c5 ("bpf: Fix array bounds error with may_goto") Signed-off-by: KaFai Wan <kafai.wan@linux.dev> Acked-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20250909144614.2991253-1-kafai.wan@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-09rqspinlock: Choose trylock fallback for NMI waitersKumar Kartikeya Dwivedi2-1/+2
Currently, out of all 3 types of waiters in the rqspinlock slow path (i.e., pending bit waiter, wait queue head waiter, and wait queue non-head waiter), only the pending bit waiter and wait queue head waiters apply deadlock checks and a timeout on their waiting loop. The assumption here was that the wait queue head's forward progress would be sufficient to identify cases where the lock owner or pending bit waiter is stuck, and non-head waiters relying on the head waiter would prove to be sufficient for their own forward progress. However, the head waiter itself can be preempted by a non-head waiter for the same lock (AA) or a different lock (ABBA) in a manner that impedes its forward progress. In such a case, non-head waiters not performing deadlock and timeout checks becomes insufficient, and the system can enter a state of lockup. This is typically not a concern with non-NMI lock acquisitions, as lock holders which in run in different contexts (IRQ, non-IRQ) use "irqsave" variants of the lock APIs, which naturally excludes such lock holders from preempting one another on the same CPU. It might seem likely that a similar case may occur for rqspinlock when programs are attached to contention tracepoints (begin, end), however, these tracepoints either precede the enqueue into the wait queue, or succeed it, therefore cannot be used to preempt a head waiter's waiting loop. We must still be careful against nested kprobe and fentry programs that may attach to the middle of the head's waiting loop to stall forward progress and invoke another rqspinlock acquisition that proceeds as a non-head waiter. To this end, drop CC_FLAGS_FTRACE from the rqspinlock.o object file. For now, this issue is resolved by falling back to a repeated trylock on the lock word from NMI context, while performing the deadlock checks to break out early in case forward progress is impossible, and use the timeout as a final fallback. A more involved fix to terminate the queue when such a condition occurs will be made as a follow up. A selftest to stress this aspect of nested NMI/non-NMI locking attempts will be added in a subsequent patch to the bpf-next tree when this fix lands and trees are synchronized. Reported-by: Josef Bacik <josef@toxicpanda.com> Fixes: 164c246571e9 ("rqspinlock: Protect waiters in queue from stalls") Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com> Link: https://lore.kernel.org/r/20250909184959.3509085-1-memxor@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-09bpf: Fix bpf_strnstr() to handle suffix match cases betterRong Tao1-1/+8
bpf_strnstr() should not treat the ending '\0' of s2 as a matching character if the parameter 'len' equal to s2 string length, for example: 1. bpf_strnstr("openat", "open", 4) = -ENOENT 2. bpf_strnstr("openat", "open", 5) = 0 This patch makes (1) return 0, fix just the `len == strlen(s2)` case. And fix a more general case when s2 is a suffix of the first len characters of s1. Fixes: e91370550f1f ("bpf: Add kfuncs for read-only string operations") Signed-off-by: Rong Tao <rongtao@cestc.cn> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/tencent_17DC57B9D16BC443837021BEACE84B7C1507@qq.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-09bpf: Fix out-of-bounds dynptr write in bpf_crypto_cryptDaniel Borkmann1-1/+1
Stanislav reported that in bpf_crypto_crypt() the destination dynptr's size is not validated to be at least as large as the source dynptr's size before calling into the crypto backend with 'len = src_len'. This can result in an OOB write when the destination is smaller than the source. Concretely, in mentioned function, psrc and pdst are both linear buffers fetched from each dynptr: psrc = __bpf_dynptr_data(src, src_len); [...] pdst = __bpf_dynptr_data_rw(dst, dst_len); [...] err = decrypt ? ctx->type->decrypt(ctx->tfm, psrc, pdst, src_len, piv) : ctx->type->encrypt(ctx->tfm, psrc, pdst, src_len, piv); The crypto backend expects pdst to be large enough with a src_len length that can be written. Add an additional src_len > dst_len check and bail out if it's the case. Note that these kfuncs are accessible under root privileges only. Fixes: 3e1c6f35409f ("bpf: make common crypto API for TC/XDP programs") Reported-by: Stanislav Fort <disclosure@aisle.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Cc: Vadim Fedorenko <vadim.fedorenko@linux.dev> Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev> Link: https://lore.kernel.org/r/20250829143657.318524-1-daniel@iogearbox.net Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-09-09Merge tag 'dma-mapping-6.17-2025-09-09' of ↵Linus Torvalds3-3/+69
git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux Pull dma-mapping fix from Marek Szyprowski: - one more fix for DMA API debugging infrastructure (Baochen Qiang) * tag 'dma-mapping-6.17-2025-09-09' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: dma-debug: don't enforce dma mapping check on noncoherent allocations
2025-09-09hrtimers: Unconditionally update target CPU base after offline timer migrationXiongfeng Wang1-8/+3
When testing softirq based hrtimers on an ARM32 board, with high resolution mode and NOHZ inactive, softirq based hrtimers fail to expire after being moved away from an offline CPU: CPU0 CPU1 hrtimer_start(..., HRTIMER_MODE_SOFT); cpu_down(CPU1) ... hrtimers_cpu_dying() // Migrate timers to CPU0 smp_call_function_single(CPU0, returgger_next_event); retrigger_next_event() if (!highres && !nohz) return; As retrigger_next_event() is a NOOP when both high resolution timers and NOHZ are inactive CPU0's hrtimer_cpu_base::softirq_expires_next is not updated and the migrated softirq timers never expire unless there is a softirq based hrtimer queued on CPU0 later. Fix this by removing the hrtimer_hres_active() and tick_nohz_active() check in retrigger_next_event(), which enforces a full update of the CPU base. As this is not a fast path the extra cost does not matter. [ tglx: Massaged change log ] Fixes: 5c0930ccaad5 ("hrtimers: Push pending hrtimers away from outgoing CPU earlier") Co-developed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250805081025.54235-1-wangxiongfeng2@huawei.com
2025-09-08tracing: Silence warning when chunk allocation fails in trace_pid_writePu Lehui1-1/+5
Syzkaller trigger a fault injection warning: WARNING: CPU: 1 PID: 12326 at tracepoint_add_func+0xbfc/0xeb0 Modules linked in: CPU: 1 UID: 0 PID: 12326 Comm: syz.6.10325 Tainted: G U 6.14.0-rc5-syzkaller #0 Tainted: [U]=USER Hardware name: Google Compute Engine/Google Compute Engine RIP: 0010:tracepoint_add_func+0xbfc/0xeb0 kernel/tracepoint.c:294 Code: 09 fe ff 90 0f 0b 90 0f b6 74 24 43 31 ff 41 bc ea ff ff ff RSP: 0018:ffffc9000414fb48 EFLAGS: 00010283 RAX: 00000000000012a1 RBX: ffffffff8e240ae0 RCX: ffffc90014b78000 RDX: 0000000000080000 RSI: ffffffff81bbd78b RDI: 0000000000000001 RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffffffffef R13: 0000000000000000 R14: dffffc0000000000 R15: ffffffff81c264f0 FS: 00007f27217f66c0(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2e80dff8 CR3: 00000000268f8000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> tracepoint_probe_register_prio+0xc0/0x110 kernel/tracepoint.c:464 register_trace_prio_sched_switch include/trace/events/sched.h:222 [inline] register_pid_events kernel/trace/trace_events.c:2354 [inline] event_pid_write.isra.0+0x439/0x7a0 kernel/trace/trace_events.c:2425 vfs_write+0x24c/0x1150 fs/read_write.c:677 ksys_write+0x12b/0x250 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f We can reproduce the warning by following the steps below: 1. echo 8 >> set_event_notrace_pid. Let tr->filtered_pids owns one pid and register sched_switch tracepoint. 2. echo ' ' >> set_event_pid, and perform fault injection during chunk allocation of trace_pid_list_alloc. Let pid_list with no pid and assign to tr->filtered_pids. 3. echo ' ' >> set_event_pid. Let pid_list is NULL and assign to tr->filtered_pids. 4. echo 9 >> set_event_pid, will trigger the double register sched_switch tracepoint warning. The reason is that syzkaller injects a fault into the chunk allocation in trace_pid_list_alloc, causing a failure in trace_pid_list_set, which may trigger double register of the same tracepoint. This only occurs when the system is about to crash, but to suppress this warning, let's add failure handling logic to trace_pid_list_set. Link: https://lore.kernel.org/20250908024658.2390398-1-pulehui@huaweicloud.com Fixes: 8d6e90983ade ("tracing: Create a sparse bitmask for pid filtering") Reported-by: syzbot+161412ccaeff20ce4dde@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/67cb890e.050a0220.d8275.022e.GAE@google.com Signed-off-by: Pu Lehui <pulehui@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-09-07Merge tag 'timers-urgent-2025-09-07' of ↵Linus Torvalds2-4/+10
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Ingo Molnar: "Fix a severe slowdown regression in the timer vDSO code related to the while() loop in __iter_div_u64_rem(), when the AUX-clock is enabled" * tag 'timers-urgent-2025-09-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: vdso/vsyscall: Avoid slow division loop in auxiliary clock update
2025-09-07Merge tag 'locking-urgent-2025-09-07' of ↵Linus Torvalds2-5/+13
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fix from Ingo Molnar: "Fix an 'allocation from atomic context' regression in the futex vmalloc variant" * tag 'locking-urgent-2025-09-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Move futex_hash_free() back to __mmput()
2025-09-07Merge tag 'perf-urgent-2025-09-07' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf event fix from Ingo Molnar: "Fix regression where PERF_EVENT_IOC_REFRESH counters miss a PMU-stop" * tag 'perf-urgent-2025-09-07' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix the POLL_HUP delivery breakage
2025-09-06tracing/osnoise: Fix null-ptr-deref in bitmap_parselist()Wang Liang1-0/+3
A crash was observed with the following output: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 92 Comm: osnoise_cpus Not tainted 6.17.0-rc4-00201-gd69eb204c255 #138 PREEMPT(voluntary) RIP: 0010:bitmap_parselist+0x53/0x3e0 Call Trace: <TASK> osnoise_cpus_write+0x7a/0x190 vfs_write+0xf8/0x410 ? do_sys_openat2+0x88/0xd0 ksys_write+0x60/0xd0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK> This issue can be reproduced by below code: fd=open("/sys/kernel/debug/tracing/osnoise/cpus", O_WRONLY); write(fd, "0-2", 0); When user pass 'count=0' to osnoise_cpus_write(), kmalloc() will return ZERO_SIZE_PTR (16) and cpulist_parse() treat it as a normal value, which trigger the null pointer dereference. Add check for the parameter 'count'. Cc: <mhiramat@kernel.org> Cc: <mathieu.desnoyers@efficios.com> Cc: <tglozar@redhat.com> Link: https://lore.kernel.org/20250906035610.3880282-1-wangliang74@huawei.com Fixes: 17f89102fe23 ("tracing/osnoise: Allow arbitrarily long CPU string") Signed-off-by: Wang Liang <wangliang74@huawei.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-09-06trace/fgraph: Fix error handlingGuenter Roeck1-1/+2
Commit edede7a6dcd7 ("trace/fgraph: Fix the warning caused by missing unregister notifier") added a call to unregister the PM notifier if register_ftrace_graph() failed. It does so unconditionally. However, the PM notifier is only registered with the first call to register_ftrace_graph(). If the first registration was successful and a subsequent registration failed, the notifier is now unregistered even if ftrace graphs are still registered. Fix the problem by only unregistering the PM notifier during error handling if there are no active fgraph registrations. Fixes: edede7a6dcd7 ("trace/fgraph: Fix the warning caused by missing unregister notifier") Closes: https://lore.kernel.org/all/63b0ba5a-a928-438e-84f9-93028dd72e54@roeck-us.net/ Cc: Ye Weihua <yeweihua4@huawei.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20250906050618.2634078-1-linux@roeck-us.net Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-09-05Merge tag 'audit-pr-20250905' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit Pull audit fix from Paul Moore: "A single small audit patch to fix a potential out-of-bounds read caused by a negative array index when comparing paths" * tag 'audit-pr-20250905' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit: audit: fix out-of-bounds read in audit_compare_dname_path()
2025-09-03audit: fix out-of-bounds read in audit_compare_dname_path()Stanislav Fort1-1/+1
When a watch on dir=/ is combined with an fsnotify event for a single-character name directly under / (e.g., creating /a), an out-of-bounds read can occur in audit_compare_dname_path(). The helper parent_len() returns 1 for "/". In audit_compare_dname_path(), when parentlen equals the full path length (1), the code sets p = path + 1 and pathlen = 1 - 1 = 0. The subsequent loop then dereferences p[pathlen - 1] (i.e., p[-1]), causing an out-of-bounds read. Fix this by adding a pathlen > 0 check to the while loop condition to prevent the out-of-bounds access. Cc: stable@vger.kernel.org Fixes: e92eebb0d611 ("audit: fix suffixed '/' filename matching") Reported-by: Stanislav Fort <disclosure@aisle.com> Suggested-by: Linus Torvalds <torvalds@linuxfoundation.org> Signed-off-by: Stanislav Fort <stanislav.fort@aisle.com> [PM: subject tweak, sign-off email fixes] Signed-off-by: Paul Moore <paul@paul-moore.com>
2025-09-03sched: Fix sched_numa_find_nth_cpu() if mask offlineChristian Loehle1-0/+2
sched_numa_find_nth_cpu() uses a bsearch to look for the 'closest' CPU in sched_domains_numa_masks and given cpus mask. However they might not intersect if all CPUs in the cpus mask are offline. bsearch will return NULL in that case, bail out instead of dereferencing a bogus pointer. The previous behaviour lead to this bug when using maxcpus=4 on an rk3399 (LLLLbb) (i.e. booting with all big CPUs offline): [ 1.422922] Unable to handle kernel paging request at virtual address ffffff8000000000 [ 1.423635] Mem abort info: [ 1.423889] ESR = 0x0000000096000006 [ 1.424227] EC = 0x25: DABT (current EL), IL = 32 bits [ 1.424715] SET = 0, FnV = 0 [ 1.424995] EA = 0, S1PTW = 0 [ 1.425279] FSC = 0x06: level 2 translation fault [ 1.425735] Data abort info: [ 1.425998] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000 [ 1.426499] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 1.426952] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 1.427428] swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000004a9f000 [ 1.428038] [ffffff8000000000] pgd=18000000f7fff403, p4d=18000000f7fff403, pud=18000000f7fff403, pmd=0000000000000000 [ 1.429014] Internal error: Oops: 0000000096000006 [#1] SMP [ 1.429525] Modules linked in: [ 1.429813] CPU: 3 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.17.0-rc4-dirty #343 PREEMPT [ 1.430559] Hardware name: Pine64 RockPro64 v2.1 (DT) [ 1.431012] pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 1.431634] pc : sched_numa_find_nth_cpu+0x2a0/0x488 [ 1.432094] lr : sched_numa_find_nth_cpu+0x284/0x488 [ 1.432543] sp : ffffffc084e1b960 [ 1.432843] x29: ffffffc084e1b960 x28: ffffff80078a8800 x27: ffffffc0846eb1d0 [ 1.433495] x26: 0000000000000000 x25: 0000000000000000 x24: 0000000000000000 [ 1.434144] x23: 0000000000000000 x22: fffffffffff7f093 x21: ffffffc081de6378 [ 1.434792] x20: 0000000000000000 x19: 0000000ffff7f093 x18: 00000000ffffffff [ 1.435441] x17: 3030303866666666 x16: 66663d736b73616d x15: ffffffc104e1b5b7 [ 1.436091] x14: 0000000000000000 x13: ffffffc084712860 x12: 0000000000000372 [ 1.436739] x11: 0000000000000126 x10: ffffffc08476a860 x9 : ffffffc084712860 [ 1.437389] x8 : 00000000ffffefff x7 : ffffffc08476a860 x6 : 0000000000000000 [ 1.438036] x5 : 000000000000bff4 x4 : 0000000000000000 x3 : 0000000000000000 [ 1.438683] x2 : 0000000000000000 x1 : ffffffc0846eb000 x0 : ffffff8000407b68 [ 1.439332] Call trace: [ 1.439559] sched_numa_find_nth_cpu+0x2a0/0x488 (P) [ 1.440016] smp_call_function_any+0xc8/0xd0 [ 1.440416] armv8_pmu_init+0x58/0x27c [ 1.440770] armv8_cortex_a72_pmu_init+0x20/0x2c [ 1.441199] arm_pmu_device_probe+0x1e4/0x5e8 [ 1.441603] armv8_pmu_device_probe+0x1c/0x28 [ 1.442007] platform_probe+0x5c/0xac [ 1.442347] really_probe+0xbc/0x298 [ 1.442683] __driver_probe_device+0x78/0x12c [ 1.443087] driver_probe_device+0xdc/0x160 [ 1.443475] __driver_attach+0x94/0x19c [ 1.443833] bus_for_each_dev+0x74/0xd4 [ 1.444190] driver_attach+0x24/0x30 [ 1.444525] bus_add_driver+0xe4/0x208 [ 1.444874] driver_register+0x60/0x128 [ 1.445233] __platform_driver_register+0x24/0x30 [ 1.445662] armv8_pmu_driver_init+0x28/0x4c [ 1.446059] do_one_initcall+0x44/0x25c [ 1.446416] kernel_init_freeable+0x1dc/0x3bc [ 1.446820] kernel_init+0x20/0x1d8 [ 1.447151] ret_from_fork+0x10/0x20 [ 1.447493] Code: 90022e21 f000e5f5 910de2b5 2a1703e2 (f8767803) [ 1.448040] ---[ end trace 0000000000000000 ]--- [ 1.448483] note: swapper/0[1] exited with preempt_count 1 [ 1.449047] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 1.449741] SMP: stopping secondary CPUs [ 1.450105] Kernel Offset: disabled [ 1.450419] CPU features: 0x000000,00080000,20002001,0400421b [ 1.450935] Memory Limit: none [ 1.451217] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- Yury: with the fix, the function returns cpu == nr_cpu_ids, and later in smp_call_function_any -> smp_call_function_single -> generic_exec_single we test the cpu for '>= nr_cpu_ids' and return -ENXIO. So everything is handled correctly. Fixes: cd7f55359c90 ("sched: add sched_numa_find_nth_cpu()") Cc: stable@vger.kernel.org Signed-off-by: Christian Loehle <christian.loehle@arm.com> Signed-off-by: Yury Norov (NVIDIA) <yury.norov@gmail.com>
2025-09-03vdso/vsyscall: Avoid slow division loop in auxiliary clock updateThomas Weißschuh2-4/+10
The call to __iter_div_u64_rem() in vdso_time_update_aux() is a wrapper around subtraction. It cannot be used to divide large numbers, as that introduces long, computationally expensive delays. A regular u64 division is also not possible in the timekeeper update path as it can be too slow. Instead of splitting the ktime_t offset into into second and subsecond components during the timekeeper update fast-path, do it together with the adjustment of tk->offs_aux in the slow-path. Equivalent to the handling of offs_boot and monotonic_to_boot. Reuse the storage of monotonic_to_boot for the new field, as it is not used by auxiliary timekeepers. Fixes: 380b84e168e5 ("vdso/vsyscall: Update auxiliary clock data in the datapage") Reported-by: Miroslav Lichvar <mlichvar@redhat.com> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20250825-vdso-auxclock-division-v1-1-a1d32a16a313@linutronix.de Closes: https://lore.kernel.org/lkml/aKwsNNWsHJg8IKzj@localhost/
2025-09-03perf: Fix the POLL_HUP delivery breakageKan Liang1-0/+1
The event_limit can be set by the PERF_EVENT_IOC_REFRESH to limit the number of events. When the event_limit reaches 0, the POLL_HUP signal should be sent. But it's missed. The corresponding counter should be stopped when the event_limit reaches 0. It was implemented in the ARCH-specific code. However, since the commit 9734e25fbf5a ("perf: Fix the throttle logic for a group"), all the ARCH-specific code has been moved to the generic code. The code to handle the event_limit was lost. Add the event->pmu->stop(event, 0); back. Fixes: 9734e25fbf5a ("perf: Fix the throttle logic for a group") Closes: https://lore.kernel.org/lkml/aICYAqM5EQUlTqtX@li-2b55cdcc-350b-11b2-a85c-a78bff51fc11.ibm.com/ Reported-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Tested-by: Sumanth Korikkar <sumanthk@linux.ibm.com> Link: https://lkml.kernel.org/r/20250811182644.1305952-1-kan.liang@linux.intel.com
2025-09-02tracing: Fix tracing_marker may trigger page fault during preempt_disableLuo Gengkun1-2/+2
Both tracing_mark_write and tracing_mark_raw_write call __copy_from_user_inatomic during preempt_disable. But in some case, __copy_from_user_inatomic may trigger page fault, and will call schedule() subtly. And if a task is migrated to other cpu, the following warning will be trigger: if (RB_WARN_ON(cpu_buffer, !local_read(&cpu_buffer->committing))) An example can illustrate this issue: process flow CPU --------------------------------------------------------------------- tracing_mark_raw_write(): cpu:0 ... ring_buffer_lock_reserve(): cpu:0 ... cpu = raw_smp_processor_id() cpu:0 cpu_buffer = buffer->buffers[cpu] cpu:0 ... ... __copy_from_user_inatomic(): cpu:0 ... # page fault do_mem_abort(): cpu:0 ... # Call schedule schedule() cpu:0 ... # the task schedule to cpu1 __buffer_unlock_commit(): cpu:1 ... ring_buffer_unlock_commit(): cpu:1 ... cpu = raw_smp_processor_id() cpu:1 cpu_buffer = buffer->buffers[cpu] cpu:1 As shown above, the process will acquire cpuid twice and the return values are not the same. To fix this problem using copy_from_user_nofault instead of __copy_from_user_inatomic, as the former performs 'access_ok' before copying. Link: https://lore.kernel.org/20250819105152.2766363-1-luogengkun@huaweicloud.com Fixes: 656c7f0d2d2b ("tracing: Replace kmap with copy_from_user() in trace_marker writing") Signed-off-by: Luo Gengkun <luogengkun@huaweicloud.com> Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-09-02trace: Remove redundant __GFP_NOWARNQianfeng Rong1-1/+1
Commit 16f5dfbc851b ("gfp: include __GFP_NOWARN in GFP_NOWAIT") made GFP_NOWAIT implicitly include __GFP_NOWARN. Therefore, explicit __GFP_NOWARN combined with GFP_NOWAIT (e.g., `GFP_NOWAIT | __GFP_NOWARN`) is now redundant. Let's clean up these redundant flags across subsystems. No functional changes. Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Link: https://lore.kernel.org/20250805023630.335719-1-rongqianfeng@vivo.com Signed-off-by: Qianfeng Rong <rongqianfeng@vivo.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-09-02dma-debug: don't enforce dma mapping check on noncoherent allocationsBaochen Qiang3-3/+69
As discussed in [1], there is no need to enforce dma mapping check on noncoherent allocations, a simple test on the returned CPU address is good enough. Add a new pair of debug helpers and use them for noncoherent alloc/free to fix this issue. Fixes: efa70f2fdc84 ("dma-mapping: add a new dma_alloc_pages API") Link: https://lore.kernel.org/all/ff6c1fe6-820f-4e58-8395-df06aa91706c@oss.qualcomm.com # 1 Signed-off-by: Baochen Qiang <baochen.qiang@oss.qualcomm.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Link: https://lore.kernel.org/r/20250828-dma-debug-fix-noncoherent-dma-check-v1-1-76e9be0dd7fc@oss.qualcomm.com
2025-08-31Merge tag 'sched_urgent_for_v6.17_rc4' of ↵Linus Torvalds2-10/+14
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Borislav Petkov: - Fix a stall on the CPU offline path due to mis-counting a deadline server task twice as part of the runqueue's running tasks count - Fix a realtime tasks starvation case where failure to enqueue a timer whose expiration time is already in the past would cause repeated attempts to re-enqueue a deadline server task which leads to starving the former, realtime one - Prevent a delayed deadline server task stop from breaking the per-runqueue bandwidth tracking - Have a function checking whether the deadline server task has stopped, return the correct value * tag 'sched_urgent_for_v6.17_rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched/deadline: Don't count nr_running for dl_server proxy tasks sched/deadline: Fix RT task potential starvation when expiry time passed sched/deadline: Always stop dl-server before changing parameters sched/deadline: Fix dl_server_stopped()
2025-08-31futex: Move futex_hash_free() back to __mmput()Sebastian Andrzej Siewior2-5/+13
To avoid a memory leak via mm_alloc() + mmdrop() the futex cleanup code has been moved to __mmdrop(). This resulted in a warnings if the futex hash table has been allocated via vmalloc() the mmdrop() was invoked from atomic context. The free path must stay in __mmput() to ensure it is invoked from preemptible context. In order to avoid the memory leak, delay the allocation of mm_struct::mm->futex_ref to futex_hash_allocate(). This works because neither the per-CPU counter nor the private hash has been allocated and therefore - futex_private_hash() callers (such as exit_pi_state_list()) don't acquire reference if there is no private hash yet. There is also no reference put. - Regular callers (futex_hash()) fallback to global hash. No reference counting here. The futex_ref member can be allocated in futex_hash_allocate() before the private hash itself is allocated. This happens either while the first thread is created or on request. In both cases the process has just a single thread so there can be either futex operation in progress or the request to create a private hash. Move futex_hash_free() back to __mmput(); Move the allocation of mm_struct::futex_ref to futex_hash_allocate(). [ bp: Fold a follow-up fix to prevent a use-after-free: https://lore.kernel.org/r/20250830213806.sEKuuGSm@linutronix.de ] Fixes: e703b7e247503 ("futex: Move futex cleanup to __mmdrop()") Closes: https://lore.kernel.org/all/20250821102721.6deae493@kernel.org/ Reported-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Link: https://lkml.kernel.org/r/20250822141238.PfnkTjFb@linutronix.de
2025-08-28Merge tag 'dma-mapping-6.17-2025-08-28' of ↵Linus Torvalds2-4/+2
git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux Pull dma-mapping fixes from Marek Szyprowski: - another small fix for arm64 systems with memory encryption (Shanker Donthineni) - fix for arm32 systems with non-standard CMA configuration (Oreoluwa Babatunde) * tag 'dma-mapping-6.17-2025-08-28' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: dma/pool: Ensure DMA_DIRECT_REMAP allocations are decrypted of: reserved_mem: Restructure call site for dma_contiguous_early_fixup()
2025-08-26sched/deadline: Don't count nr_running for dl_server proxy tasksYicong Yang1-2/+6
On CPU offline the kernel stalled with below call trace: INFO: task kworker/0:1:11 blocked for more than 120 seconds. cpuhp hold the cpu hotplug lock endless and stalled vmstat_shepherd. This is because we count nr_running twice on cpuhp enqueuing and failed the wait condition of cpuhp: enqueue_task_fair() // pick cpuhp from idle, rq->nr_running = 0 dl_server_start() [...] add_nr_running() // rq->nr_running = 1 add_nr_running() // rq->nr_running = 2 [switch to cpuhp, waiting on balance_hotplug_wait()] rcuwait_wait_event(rq->nr_running == 1 && ...) // failed, rq->nr_running=2 schedule() // wait again It doesn't make sense to count the dl_server towards runnable tasks, since it runs other tasks. Fixes: 63ba8422f876 ("sched/deadline: Introduce deadline servers") Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20250627035420.37712-1-yangyicong@huawei.com
2025-08-26sched/deadline: Fix RT task potential starvation when expiry time passedkuyo chang1-3/+5
[Symptom] The fair server mechanism, which is intended to prevent fair starvation when higher-priority tasks monopolize the CPU. Specifically, RT tasks on the runqueue may not be scheduled as expected. [Analysis] The log "sched: DL replenish lagged too much" triggered. By memory dump of dl_server: curr = 0xFFFFFF80D6A0AC00 ( dl_server = 0xFFFFFF83CD5B1470( dl_runtime = 0x02FAF080, dl_deadline = 0x3B9ACA00, dl_period = 0x3B9ACA00, dl_bw = 0xCCCC, dl_density = 0xCCCC, runtime = 0x02FAF080, deadline = 0x0000082031EB0E80, flags = 0x0, dl_throttled = 0x0, dl_yielded = 0x0, dl_non_contending = 0x0, dl_overrun = 0x0, dl_server = 0x1, dl_server_active = 0x1, dl_defer = 0x1, dl_defer_armed = 0x0, dl_defer_running = 0x1, dl_timer = ( node = ( expires = 0x000008199756E700), _softexpires = 0x000008199756E700, function = 0xFFFFFFDB9AF44D30 = dl_task_timer, base = 0xFFFFFF83CD5A12C0, state = 0x0, is_rel = 0x0, is_soft = 0x0, clock_update_flags = 0x4, clock = 0x000008204A496900, - The timer expiration time (rq->curr->dl_server->dl_timer->expires) is already in the past, indicating the timer has expired. - The timer state (rq->curr->dl_server->dl_timer->state) is 0. [Suspected Root Cause] The relevant code flow in the throttle path of update_curr_dl_se() as follows: dequeue_dl_entity(dl_se, 0); // the DL entity is dequeued if (unlikely(is_dl_boosted(dl_se) || !start_dl_timer(dl_se))) { if (dl_server(dl_se)) // timer registration fails enqueue_dl_entity(dl_se, ENQUEUE_REPLENISH);//enqueue immediately ... } The failure of `start_dl_timer` is caused by attempting to register a timer with an expiration time that is already in the past. When this situation persists, the code repeatedly re-enqueues the DL entity without properly replenishing or restarting the timer, resulting in RT task may not be scheduled as expected. [Proposed Solution]: Instead of immediately re-enqueuing the DL entity on timer registration failure, this change ensures the DL entity is properly replenished and the timer is restarted, preventing RT potential starvation. Fixes: 63ba8422f876 ("sched/deadline: Introduce deadline servers") Signed-off-by: kuyo chang <kuyo.chang@mediatek.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Closes: https://lore.kernel.org/CAMuHMdXn4z1pioTtBGMfQM0jsLviqS2jwysaWXpoLxWYoGa82w@mail.gmail.com Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Jiri Slaby <jirislaby@kernel.org> Tested-by: Diederik de Haas <didi.debian@cknow.org> Link: https://lkml.kernel.org/r/20250615131129.954975-1-kuyo.chang@mediatek.com
2025-08-26sched/deadline: Always stop dl-server before changing parametersJuri Lelli1-4/+2
Commit cccb45d7c4295 ("sched/deadline: Less agressive dl_server handling") reduced dl-server overhead