On Mon, Aug 05, 2024 at 11:20:11AM +0200, Juri Lelli wrote: SNIP > [ 154.566882] BUG: kernel NULL pointer dereference, address: 000000000000040c > [ 154.573844] #PF: supervisor read access in kernel mode > [ 154.578982] #PF: error_code(0x0000) - not-present page > [ 154.584122] PGD 146fff067 P4D 146fff067 PUD 10fc00067 PMD 0 > [ 154.589780] Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI > [ 154.594659] CPU: 28 UID: 0 PID: 2234 Comm: thread0-13 Kdump: loaded Not tainted 6.11.0-rc1 #8 > [ 154.603179] Hardware name: Dell Inc. PowerEdge R740/04FC42, BIOS 2.10.2 02/24/2021 > [ 154.610744] RIP: 0010:bpf_prog_ec8173ca2868eb50_handle__sched_pi_setprio+0x22/0xd7 > [ 154.618310] Code: cc cc cc cc cc cc cc cc 0f 1f 44 00 00 66 90 55 48 89 e5 48 81 ec 30 00 00 00 53 41 55 41 56 48 89 fb 4c 8b 6b 00 4c 8b 73 08 <41> 8b be 0c 04 00 00 48 83 ff 06 0f 85 9b 00 00 00 41 8b be c0 09 > [ 154.637052] RSP: 0018:ffffabac60aebbc0 EFLAGS: 00010086 > [ 154.642278] RAX: ffffffffc03fba5c RBX: ffffabac60aebc28 RCX: 000000000000001f > [ 154.649411] RDX: ffff95a90b4e4180 RSI: ffffabac4e639048 RDI: ffffabac60aebc28 > [ 154.656544] RBP: ffffabac60aebc08 R08: 00000023fce7674a R09: ffff95a91d85af38 > [ 154.663674] R10: ffff95a91d85a0c0 R11: 000000003357e518 R12: 0000000000000000 > [ 154.670807] R13: ffff95a90b4e4180 R14: 0000000000000000 R15: 0000000000000001 > [ 154.677939] FS: 00007ffa6d600640(0000) GS:ffff95c01bf00000(0000) knlGS:0000000000000000 > [ 154.686026] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 154.691769] CR2: 000000000000040c CR3: 000000014b9f2005 CR4: 00000000007706f0 > [ 154.698903] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > [ 154.706035] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > [ 154.713168] PKRU: 55555554 > [ 154.715879] Call Trace: > [ 154.718332] <TASK> > [ 154.720439] ? __die+0x20/0x70 > [ 154.723498] ? page_fault_oops+0x75/0x170 > [ 154.727508] ? sysvec_irq_work+0xb/0x90 > [ 154.731348] ? exc_page_fault+0x64/0x140 > [ 154.735275] ? asm_exc_page_fault+0x22/0x30 > [ 154.739461] ? 0xffffffffc03fba5c > [ 154.742780] ? bpf_prog_ec8173ca2868eb50_handle__sched_pi_setprio+0x22/0xd7 hi, reproduced.. AFAICS looks like the bpf program somehow lost the booster != NULL check and just load the policy field without it and crash when booster is rubbish int handle__sched_pi_setprio(u64 * ctx): ; int handle__sched_pi_setprio(u64 *ctx) 0: (bf) r6 = r1 ; struct task_struct *boosted = (void *) ctx[0]; 1: (79) r7 = *(u64 *)(r6 +0) ; struct task_struct *booster = (void *) ctx[1]; 2: (79) r8 = *(u64 *)(r6 +8) ; if (booster->policy != SCHED_DEADLINE) curious why the check disappeared, because object file has it, so I guess verifier took it out for some reason, will check jirka > [ 154.749737] bpf_trace_run2+0x71/0xf0 > [ 154.753405] ? raw_spin_rq_lock_nested+0x19/0x80 > [ 154.758023] rt_mutex_setprio+0x1bf/0x3d0 > [ 154.762035] ? hrtimer_nanosleep+0xb1/0x190 > [ 154.766221] ? rseq_get_rseq_cs+0x1d/0x220 > [ 154.770320] mark_wakeup_next_waiter+0x85/0xd0 > [ 154.774765] __rt_mutex_futex_unlock+0x1c/0x40 > [ 154.779211] futex_unlock_pi+0x240/0x310 > [ 154.783137] do_futex+0x149/0x1d0 > [ 154.786457] __x64_sys_futex+0x73/0x1d0 > [ 154.790294] do_syscall_64+0x79/0x150 > [ 154.793962] ? update_process_times+0x8c/0xa0 > [ 154.798319] ? timerqueue_add+0x9b/0xc0 > [ 154.802158] ? enqueue_hrtimer+0x35/0x90 > [ 154.806085] ? __hrtimer_run_queues+0x141/0x2a0 > [ 154.810616] ? ktime_get+0x34/0xc0 > [ 154.814021] ? clockevents_program_event+0x92/0x100 > [ 154.818901] ? hrtimer_interrupt+0x129/0x240 > [ 154.823174] ? sched_clock+0xc/0x30 > [ 154.826666] ? sched_clock_cpu+0xb/0x190 > [ 154.830591] ? irqtime_account_irq+0x41/0xc0 > [ 154.834865] ? clear_bhb_loop+0x45/0xa0 > [ 154.838702] ? clear_bhb_loop+0x45/0xa0 > [ 154.842542] ? clear_bhb_loop+0x45/0xa0 > [ 154.846381] entry_SYSCALL_64_after_hwframe+0x76/0x7e > [ 154.851434] RIP: 0033:0x7ffa75a8e956 > [ 154.855011] Code: 0f 86 26 fe ff ff 83 c0 16 83 e0 f7 0f 85 2d ff ff ff e9 15 fe ff ff 40 80 f6 87 45 31 d2 31 d2 4c 89 c7 b8 ca 00 00 00 0f 05 <48> 3d 00 f0 ff ff 0f 86 5b fd ff ff 83 f8 92 0f 84 52 fd ff ff 83 > [ 154.873757] RSP: 002b:00007ffa6d5ffb98 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca > [ 154.881321] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ffa75a8e956 > [ 154.888454] RDX: 0000000000000000 RSI: 0000000000000087 RDI: 000000003357e518 > [ 154.895587] RBP: 0000000000000002 R08: 000000003357e518 R09: 0000000000000000 > [ 154.902718] R10: 0000000000000000 R11: 0000000000000246 R12: 000000003357e518 > [ 154.909852] R13: 000000003357e510 R14: 0000000000000000 R15: 000000003357e8e8 > [ 154.916983] </TASK> > [ 154.919176] Modules linked in: qrtr rfkill vfat fat intel_rapl_msr intel_rapl_common intel_uncore_frequency intel_uncore_frequency_common skx_edac skx_edac_common nfit libnvdimm x86_pkg_temp_thermal coretemp ipmi_ssif rapl iTCO_wdt iTCO_vendor_support dell_pc intel_cstate dell_smbios platform_profile mei_me i2c_i801 acpi_power_meter dcdbas intel_uncore dell_wmi_descriptor wmi_bmof pcspkr ipmi_si mei i2c_smbus lpc_ich acpi_ipmi intel_pch_thermal ipmi_devintf ipmi_msghandler xfs libcrc32c sr_mod sd_mod cdrom sg uas usb_storage mgag200 drm_shmem_helper drm_kms_helper ahci crct10dif_pclmul libahci crc32_pclmul i40e drm igb crc32c_intel libata dca megaraid_sas ghash_clmulni_intel i2c_algo_bit libie wmi dm_mirror dm_region_hash dm_log dm_mod fuse > [ 154.984673] CR2: 000000000000040c > --->8--- > > Apologies for the rather long report, but I tried to provide hopefully > enough information already for whoever might have time to take a look at > this. Please let me know if I'm either wrong in what I'm trying to do or > how to proceed (if you need more info, etc.). > > Thank you in advance! > > Best, > Juri > >
