Test PR for workflow testing #7
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Signed-off-by: sgaud-quic <sgaud@qti.qualcomm.com>
Test PR for CI workflow test
sgaud-quic
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Jul 21, 2025
A crash in conntrack was reported while trying to unlink the conntrack
entry from the hash bucket list:
[exception RIP: __nf_ct_delete_from_lists+172]
[..]
#7 [ff539b5a2b043aa0] nf_ct_delete at ffffffffc124d421 [nf_conntrack]
#8 [ff539b5a2b043ad0] nf_ct_gc_expired at ffffffffc124d999 [nf_conntrack]
#9 [ff539b5a2b043ae0] __nf_conntrack_find_get at ffffffffc124efbc [nf_conntrack]
[..]
The nf_conn struct is marked as allocated from slab but appears to be in
a partially initialised state:
ct hlist pointer is garbage; looks like the ct hash value
(hence crash).
ct->status is equal to IPS_CONFIRMED|IPS_DYING, which is expected
ct->timeout is 30000 (=30s), which is unexpected.
Everything else looks like normal udp conntrack entry. If we ignore
ct->status and pretend its 0, the entry matches those that are newly
allocated but not yet inserted into the hash:
- ct hlist pointers are overloaded and store/cache the raw tuple hash
- ct->timeout matches the relative time expected for a new udp flow
rather than the absolute 'jiffies' value.
If it were not for the presence of IPS_CONFIRMED,
__nf_conntrack_find_get() would have skipped the entry.
Theory is that we did hit following race:
cpu x cpu y cpu z
found entry E found entry E
E is expired <preemption>
nf_ct_delete()
return E to rcu slab
init_conntrack
E is re-inited,
ct->status set to 0
reply tuplehash hnnode.pprev
stores hash value.
cpu y found E right before it was deleted on cpu x.
E is now re-inited on cpu z. cpu y was preempted before
checking for expiry and/or confirm bit.
->refcnt set to 1
E now owned by skb
->timeout set to 30000
If cpu y were to resume now, it would observe E as
expired but would skip E due to missing CONFIRMED bit.
nf_conntrack_confirm gets called
sets: ct->status |= CONFIRMED
This is wrong: E is not yet added
to hashtable.
cpu y resumes, it observes E as expired but CONFIRMED:
<resumes>
nf_ct_expired()
-> yes (ct->timeout is 30s)
confirmed bit set.
cpu y will try to delete E from the hashtable:
nf_ct_delete() -> set DYING bit
__nf_ct_delete_from_lists
Even this scenario doesn't guarantee a crash:
cpu z still holds the table bucket lock(s) so y blocks:
wait for spinlock held by z
CONFIRMED is set but there is no
guarantee ct will be added to hash:
"chaintoolong" or "clash resolution"
logic both skip the insert step.
reply hnnode.pprev still stores the
hash value.
unlocks spinlock
return NF_DROP
<unblocks, then
crashes on hlist_nulls_del_rcu pprev>
In case CPU z does insert the entry into the hashtable, cpu y will unlink
E again right away but no crash occurs.
Without 'cpu y' race, 'garbage' hlist is of no consequence:
ct refcnt remains at 1, eventually skb will be free'd and E gets
destroyed via: nf_conntrack_put -> nf_conntrack_destroy -> nf_ct_destroy.
To resolve this, move the IPS_CONFIRMED assignment after the table
insertion but before the unlock.
Pablo points out that the confirm-bit-store could be reordered to happen
before hlist add resp. the timeout fixup, so switch to set_bit and
before_atomic memory barrier to prevent this.
It doesn't matter if other CPUs can observe a newly inserted entry right
before the CONFIRMED bit was set:
Such event cannot be distinguished from above "E is the old incarnation"
case: the entry will be skipped.
Also change nf_ct_should_gc() to first check the confirmed bit.
The gc sequence is:
1. Check if entry has expired, if not skip to next entry
2. Obtain a reference to the expired entry.
3. Call nf_ct_should_gc() to double-check step 1.
nf_ct_should_gc() is thus called only for entries that already failed an
expiry check. After this patch, once the confirmed bit check passes
ct->timeout has been altered to reflect the absolute 'best before' date
instead of a relative time. Step 3 will therefore not remove the entry.
Without this change to nf_ct_should_gc() we could still get this sequence:
1. Check if entry has expired.
2. Obtain a reference.
3. Call nf_ct_should_gc() to double-check step 1:
4 - entry is still observed as expired
5 - meanwhile, ct->timeout is corrected to absolute value on other CPU
and confirm bit gets set
6 - confirm bit is seen
7 - valid entry is removed again
First do check 6), then 4) so the gc expiry check always picks up either
confirmed bit unset (entry gets skipped) or expiry re-check failure for
re-inited conntrack objects.
This change cannot be backported to releases before 5.19. Without
commit 8a75a2c ("netfilter: conntrack: remove unconfirmed list")
|= IPS_CONFIRMED line cannot be moved without further changes.
Cc: Razvan Cojocaru <rzvncj@gmail.com>
Link: https://lore.kernel.org/netfilter-devel/20250627142758.25664-1-fw@strlen.de/
Link: https://lore.kernel.org/netfilter-devel/4239da15-83ff-4ca4-939d-faef283471bb@gmail.com/
Fixes: 1397af5 ("netfilter: conntrack: remove the percpu dying list")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
sgaud-quic
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Oct 15, 2025
When s_start() fails to allocate memory for set_event_iter, it returns NULL before acquiring event_mutex. However, the corresponding s_stop() function always tries to unlock the mutex, causing a lock imbalance warning: WARNING: bad unlock balance detected! 6.17.0-rc7-00175-g2b2e0c04f78c #7 Not tainted ------------------------------------- syz.0.85611/376514 is trying to release lock (event_mutex) at: [<ffffffff8dafc7a4>] traverse.part.0.constprop.0+0x2c4/0x650 fs/seq_file.c:131 but there are no more locks to release! The issue was introduced by commit b355247 ("tracing: Cache ':mod:' events for modules not loaded yet") which added the kzalloc() allocation before the mutex lock, creating a path where s_start() could return without locking the mutex while s_stop() would still try to unlock it. Fix this by unconditionally acquiring the mutex immediately after allocation, regardless of whether the allocation succeeded. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20250929113238.3722055-1-sashal@kernel.org Fixes: b355247 ("tracing: Cache ":mod:" events for modules not loaded yet") Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
sgaud-quic
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Nov 17, 2025
Replace the hack added by commit f958bd2 ("KVM: x86: Fix potential put_fpu() w/o load_fpu() on MPX platform") with a more robust approach of unloading+reloading guest FPU state based on whether or not the vCPU's FPU is currently in-use, i.e. currently loaded. This fixes a bug on hosts that support CET but not MPX, where kvm_arch_vcpu_ioctl_get_mpstate() neglects to load FPU state (it only checks for MPX support) and leads to KVM attempting to put FPU state due to kvm_apic_accept_events() triggering INIT emulation. E.g. on a host with CET but not MPX, syzkaller+KASAN generates: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000004: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 211 UID: 0 PID: 20451 Comm: syz.9.26 Tainted: G S 6.18.0-smp-DEV #7 NONE Tainted: [S]=CPU_OUT_OF_SPEC Hardware name: Google Izumi/izumi, BIOS 0.20250729.1-0 07/29/2025 RIP: 0010:fpu_swap_kvm_fpstate+0x3ce/0x610 ../arch/x86/kernel/fpu/core.c:377 RSP: 0018:ff1100410c167cc0 EFLAGS: 00010202 RAX: 0000000000000004 RBX: 0000000000000020 RCX: 00000000000001aa RDX: 00000000000001ab RSI: ffffffff817bb960 RDI: 0000000022600000 RBP: dffffc0000000000 R08: ff110040d23c8007 R09: 1fe220081a479000 R10: dffffc0000000000 R11: ffe21c081a479001 R12: ff110040d23c8d98 R13: 00000000fffdc578 R14: 0000000000000000 R15: ff110040d23c8d90 FS: 00007f86dd1876c0(0000) GS:ff11007fc969b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f86dd186fa8 CR3: 00000040d1dfa003 CR4: 0000000000f73ef0 PKRU: 80000000 Call Trace: <TASK> kvm_vcpu_reset+0x80d/0x12c0 ../arch/x86/kvm/x86.c:11818 kvm_apic_accept_events+0x1cb/0x500 ../arch/x86/kvm/lapic.c:3489 kvm_arch_vcpu_ioctl_get_mpstate+0xd0/0x4e0 ../arch/x86/kvm/x86.c:12145 kvm_vcpu_ioctl+0x5e2/0xed0 ../virt/kvm/kvm_main.c:4539 __se_sys_ioctl+0x11d/0x1b0 ../fs/ioctl.c:51 do_syscall_x64 ../arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x6e/0x940 ../arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f86de71d9c9 </TASK> with a very simple reproducer: r0 = openat$kvm(0xffffffffffffff9c, &(0x7f0000000000), 0x80b00, 0x0) r1 = ioctl$KVM_CREATE_VM(r0, 0xae01, 0x0) ioctl$KVM_CREATE_IRQCHIP(r1, 0xae60) r2 = ioctl$KVM_CREATE_VCPU(r1, 0xae41, 0x0) ioctl$KVM_SET_IRQCHIP(r1, 0x8208ae63, ...) ioctl$KVM_GET_MP_STATE(r2, 0x8004ae98, &(0x7f00000000c0)) Alternatively, the MPX hack in GET_MP_STATE could be extended to cover CET, but from a "don't break existing functionality" perspective, that isn't any less risky than peeking at the state of in_use, and it's far less robust for a long term solution (as evidenced by this bug). Reported-by: Alexander Potapenko <glider@google.com> Fixes: 69cc3e8 ("KVM: x86: Add XSS support for CET_KERNEL and CET_USER") Reviewed-by: Yao Yuan <yaoyuan@linux.alibaba.com> Reviewed-by: Chao Gao <chao.gao@intel.com> Link: https://patch.msgid.link/20251030185802.3375059-2-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
sgaud-quic
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Dec 22, 2025
When interrupting perf stat in repeat mode with a signal the signal is passed to the child process but the repeat doesn't terminate: ``` $ perf stat -v --null --repeat 10 sleep 1 Control descriptor is not initialized [ perf stat: executing run #1 ... ] [ perf stat: executing run #2 ... ] ^Csleep: Interrupt [ perf stat: executing run #3 ... ] [ perf stat: executing run #4 ... ] [ perf stat: executing run #5 ... ] [ perf stat: executing run #6 ... ] [ perf stat: executing run #7 ... ] [ perf stat: executing run #8 ... ] [ perf stat: executing run #9 ... ] [ perf stat: executing run #10 ... ] Performance counter stats for 'sleep 1' (10 runs): 0.9500 +- 0.0512 seconds time elapsed ( +- 5.39% ) 0.01user 0.02system 0:09.53elapsed 0%CPU (0avgtext+0avgdata 18940maxresident)k 29944inputs+0outputs (0major+2629minor)pagefaults 0swaps ``` Terminate the repeated run and give a reasonable exit value: ``` $ perf stat -v --null --repeat 10 sleep 1 Control descriptor is not initialized [ perf stat: executing run #1 ... ] [ perf stat: executing run #2 ... ] [ perf stat: executing run #3 ... ] ^Csleep: Interrupt Performance counter stats for 'sleep 1' (10 runs): 0.680 +- 0.321 seconds time elapsed ( +- 47.16% ) Command exited with non-zero status 130 0.00user 0.01system 0:02.05elapsed 0%CPU (0avgtext+0avgdata 70688maxresident)k 0inputs+0outputs (0major+5002minor)pagefaults 0swaps ``` Note, this also changes the exit value for non-repeat runs when interrupted by a signal. Reported-by: Ingo Molnar <mingo@kernel.org> Closes: https://lore.kernel.org/lkml/aS5wjmbAM9ka3M2g@gmail.com/ Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Thomas Richter <tmricht@linux.ibm.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
sgaud-quic
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Dec 22, 2025
Since commit a735831 ("drm/nouveau: vendor in drm_encoder_slave API") nouveau appears to be broken for all dispnv04 GPUs (before NV50). Depending on the kernel version, either having no display output and hanging in kernel for a long time, or even oopsing in the cleanup path like: Hardware name: PowerMac11,2 PPC970MP 0x440101 PowerMac ... nouveau 0000:0a:00.0: drm: 0x14C5: Parsing digital output script table BUG: Unable to handle kernel data access on read at 0x00041520 Faulting instruction address: 0xc0003d0001be0844 Oops: Kernel access of bad area, sig: 11 [#1] BE PAGE_SIZE=4K MMU=Hash SMP NR_CPUS=8 NUMA PowerMac Modules linked in: windfarm_cpufreq_clamp windfarm_smu_sensors windfarm_smu_controls windfarm_pm112 snd_aoa_codec_onyx snd_aoa_fabric_layout snd_aoa windfarm_pid jo apple_mfi_fastcharge rndis_host cdc_ether usbnet mii snd_aoa_i2sbus snd_aoa_soundbus snd_pcm snd_timer snd soundcore rack_meter windfarm_smu_sat windfarm_max6690_s m75_sensor windfarm_core gpu_sched drm_gpuvm drm_exec drm_client_lib drm_ttm_helper ttm drm_display_helper drm_kms_helper drm drm_panel_orientation_quirks syscopyar _sys_fops i2c_algo_bit backlight uio_pdrv_genirq uio uninorth_agp agpgart zram dm_mod dax ipv6 nfsv4 dns_resolver nfs lockd grace sunrpc offb cfbfillrect cfbimgblt ont input_leds sr_mod cdrom sd_mod uas ata_generic hid_apple hid_generic usbhid hid usb_storage pata_macio sata_svw libata firewire_ohci scsi_mod firewire_core ohci ehci_pci ehci_hcd tg3 ohci_hcd libphy usbcore usb_common nls_base led_class CPU: 0 UID: 0 PID: 245 Comm: (udev-worker) Not tainted 6.14.0-09584-g7d06015d936c #7 PREEMPTLAZY Hardware name: PowerMac11,2 PPC970MP 0x440101 PowerMac NIP: c0003d0001be0844 LR: c0003d0001be0830 CTR: 0000000000000000 REGS: c0000000053f70e0 TRAP: 0300 Not tainted (6.14.0-09584-g7d06015d936c) MSR: 9000000000009032 <SF,HV,EE,ME,IR,DR,RI> CR: 24222220 XER: 00000000 DAR: 0000000000041520 DSISR: 40000000 IRQMASK: 0 \x0aGPR00: c0003d0001be0830 c0000000053f7380 c0003d0000911900 c000000007bc6800 \x0aGPR04: 0000000000000000 0000000000000000 c000000007bc6e70 0000000000000001 \x0aGPR08: 01f3040000000000 0000000000041520 0000000000000000 c0003d0000813958 \x0aGPR12: c000000000071a48 c000000000e28000 0000000000000020 0000000000000000 \x0aGPR16: 0000000000000000 0000000000f52630 0000000000000000 0000000000000000 \x0aGPR20: 0000000000000000 0000000000000000 0000000000000001 c0003d0000928528 \x0aGPR24: c0003d0000928598 0000000000000000 c000000007025480 c000000007025480 \x0aGPR28: c0000000010b4000 0000000000000000 c000000007bc1800 c000000007bc6800 NIP [c0003d0001be0844] nv_crtc_destroy+0x44/0xd4 [nouveau] LR [c0003d0001be0830] nv_crtc_destroy+0x30/0xd4 [nouveau] Call Trace: [c0000000053f7380] [c0003d0001be0830] nv_crtc_destroy+0x30/0xd4 [nouveau] (unreliable) [c0000000053f73c0] [c0003d00007f7bf4] drm_mode_config_cleanup+0x27c/0x30c [drm] [c0000000053f7490] [c0003d0001bdea50] nouveau_display_create+0x1cc/0x550 [nouveau] [c0000000053f7500] [c0003d0001bcc29c] nouveau_drm_device_init+0x1c8/0x844 [nouveau] [c0000000053f75e0] [c0003d0001bcc9ec] nouveau_drm_probe+0xd4/0x1e0 [nouveau] [c0000000053f7670] [c000000000557d24] local_pci_probe+0x50/0xa8 [c0000000053f76f0] [c000000000557fa8] pci_device_probe+0x22c/0x240 [c0000000053f7760] [c0000000005fff3c] really_probe+0x188/0x31c [c0000000053f77e0] [c000000000600204] __driver_probe_device+0x134/0x13c [c0000000053f7860] [c0000000006002c0] driver_probe_device+0x3c/0xb4 [c0000000053f78a0] [c000000000600534] __driver_attach+0x118/0x128 [c0000000053f78e0] [c0000000005fe038] bus_for_each_dev+0xa8/0xf4 [c0000000053f7950] [c0000000005ff460] driver_attach+0x2c/0x40 [c0000000053f7970] [c0000000005fea68] bus_add_driver+0x130/0x278 [c0000000053f7a00] [c00000000060117c] driver_register+0x9c/0x1a0 [c0000000053f7a80] [c00000000055623c] __pci_register_driver+0x5c/0x70 [c0000000053f7aa0] [c0003d0001c058a0] nouveau_drm_init+0x254/0x278 [nouveau] [c0000000053f7b10] [c00000000000e9bc] do_one_initcall+0x84/0x268 [c0000000053f7bf0] [c0000000001a0ba0] do_init_module+0x70/0x2d8 [c0000000053f7c70] [c0000000001a42bc] init_module_from_file+0xb4/0x108 [c0000000053f7d50] [c0000000001a4504] sys_finit_module+0x1ac/0x478 [c0000000053f7e10] [c000000000023230] system_call_exception+0x1a4/0x20c [c0000000053f7e50] [c00000000000c554] system_call_common+0xf4/0x258 --- interrupt: c00 at 0xfd5f988 NIP: 000000000fd5f988 LR: 000000000ff9b148 CTR: 0000000000000000 REGS: c0000000053f7e80 TRAP: 0c00 Not tainted (6.14.0-09584-g7d06015d936c) MSR: 100000000000d032 <HV,EE,PR,ME,IR,DR,RI> CR: 28222244 XER: 00000000 IRQMASK: 0 \x0aGPR00: 0000000000000161 00000000ffcdc2d0 00000000405db160 0000000000000020 \x0aGPR04: 000000000ffa2c9c 0000000000000000 000000000000001f 0000000000000045 \x0aGPR08: 0000000011a13770 0000000000000000 0000000000000000 0000000000000000 \x0aGPR12: 0000000000000000 0000000010249d8c 0000000000000020 0000000000000000 \x0aGPR16: 0000000000000000 0000000000f52630 0000000000000000 0000000000000000 \x0aGPR20: 0000000000000000 0000000000000000 0000000000000000 0000000011a11a70 \x0aGPR24: 0000000011a13580 0000000011a11950 0000000011a11a70 0000000000020000 \x0aGPR28: 000000000ffa2c9c 0000000000000000 000000000ffafc40 0000000011a11a70 NIP [000000000fd5f988] 0xfd5f988 LR [000000000ff9b148] 0xff9b148 --- interrupt: c00 Code: f821ffc1 418200ac e93f0000 e9290038 e9291468 eba90000 48026c0d e8410018 e93f06aa 3d290001 392982a4 79291f24 <7fdd482a> 2c3e0000 41820030 7fc3f378 ---[ end trace 0000000000000000 ]--- This is caused by the i2c encoder modules vendored into nouveau/ now depending on the equally vendored nouveau_i2c_encoder_destroy function. Trying to auto-load this modules hangs on nouveau initialization until timeout, and nouveau continues without i2c video encoders. Fix by avoiding nouveau dependency by __always_inlining that helper functions into those i2c video encoder modules. Fixes: a735831 ("drm/nouveau: vendor in drm_encoder_slave API") Signed-off-by: René Rebe <rene@exactco.de> Reviewed-by: Lyude Paul <lyude@redhat.com> [Lyude: fixed commit reference in description] Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patch.msgid.link/20251202.164952.2216481867721531616.rene@exactco.de
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