Re: Bad vmalloc address during BPF hooks unload

[Jiri Olsa <olsajiri@gmail.com>]

On Tue, Jun 03, 2025 at 04:13:18PM -0400, Andrey Grodzovsky wrote:
> Hi, we observe bellow random warning occasionally during BPF hooks unload,
> we only see it on rhel8 kernels ranging from 8.6-8.10 so it might be
> something RHEL specific and not upstream issues, i still was hoping to get
> some advise or clues from BPF experts here.

hi,
unless you reproduce on upstream or some stable kernel I'm afraid there's not
much that can be done in here

jirka


> 
> Thanks,Andrey
> 
> [ 5714.071613] WARNING: CPU: 0 PID: 20653 at mm/vmalloc.c:330
> vmalloc_to_page+0x21e/0x230
> [ 5714.079668] Modules linked in: nft_chain_nat ipt_MASQUERADE nf_nat
> nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 veth nft_counter ipt_REJECT
> nf_reject_ipv4 nft_compat falcon_lsm_pinned_7413(E) binfmt_misc tcp_diag
> udp_diag inet_diag nf_tables nfnetlink overlay intel_rapl_msr
> intel_rapl_common amd_energy pcspkr i2c_piix4 xfs libcrc32c nvme_tcp(X)
> nvme_fabrics sd_mod sg crct10dif_pclmul crc32_pclmul crc32c_intel virtio_net
> ghash_clmulni_intel net_failover virtio_scsi failover serio_raw nvme
> nvme_core t10_pi dm_mirror dm_region_hash dm_log dm_mod fuse [last unloaded:
> falcon_nf_netcontain]
> [ 5714.131372] Red Hat flags: eBPF/event eBPF/rawtrace
> [ 5714.136351] CPU: 0 PID: 20653 Comm: falcon-sensor-b Kdump: loaded
> Tainted: G            E  X --------- -  - 4.18.0-477.10.1.el8_8.x86_64 #1
> [ 5714.148964] Hardware name: Google Google Compute Engine/Google Compute
> Engine, BIOS Google 05/07/2025
> [ 5714.158283] RIP: 0010:vmalloc_to_page+0x21e/0x230
> [ 5714.163086] Code: 28 f1 b0 00 48 81 e7 00 00 00 c0 e9 19 ff ff ff 48 8b
> 3d 55 5b 0d 01 48 81 e7 00 f0 ff ff 48 89 fa eb 8c 0f 0b e9 10 fe ff ff <0f>
> 0b 31 c0 e9 f9 f0 b0 00 66 0f 1f 84 00 00 00 00 00 0f 1f 44 00
> [ 5714.181949] RSP: 0018:ffffad99017b3d10 EFLAGS: 00010293
> [ 5714.187271] RAX: 0000000000000063 RBX: ffffdead05829d80 RCX:
> 0000000000000000
> [ 5714.194500] RDX: 0000000000000000 RSI: ffffffffc2200049 RDI:
> 0000000000000000
> [ 5714.201749] RBP: ffffffffc21ff049 R08: 0000000000000000 R09:
> 0000000000000001
> [ 5714.208977] R10: ffff8b901bb403c0 R11: 0000000000000001 R12:
> 0000000000000001
> [ 5714.216206] R13: ffffad99017b3d5f R14: ffffffffc2200049 R15:
> ffff8b900a0bdd80
> [ 5714.223438] FS:  00007ff766da4c00(0000) GS:ffff8b9137c00000(0000)
> knlGS:0000000000000000
> [ 5714.231623] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 5714.237466] CR2: 0000603000261000 CR3: 00000001b3438004 CR4:
> 0000000000370ef0
> [ 5714.244699] Call Trace:
> [ 5714.247245]  __text_poke+0x207/0x260
> [ 5714.250926]  text_poke_bp_batch+0x85/0x270
> [ 5714.255122]  ? bpf_trampoline_6442489046_0+0x49/0x1000
> [ 5714.260361]  text_poke_bp+0x44/0x70
> [ 5714.263954]  __bpf_arch_text_poke+0x1a2/0x1b0
> [ 5714.268412]  bpf_tramp_image_put+0x2b/0x60
> [ 5714.272608]  bpf_trampoline_update+0x205/0x440
> [ 5714.277151]  bpf_trampoline_unlink_prog+0x7a/0xc0
> [ 5714.281954]  bpf_tracing_link_release+0x16/0x40
> [ 5714.286585]  bpf_link_free+0x2b/0x50
> [ 5714.290263]  bpf_link_release+0x11/0x20
> [ 5714.294195]  __fput+0xbe/0x250
> [ 5714.297348]  task_work_run+0x8a/0xb0
> [ 5714.301021]  exit_to_usermode_loop+0xef/0x100
> [ 5714.305477]  do_syscall_64+0x19c/0x1b0
> [ 5714.309324]  entry_SYSCALL_64_after_hwframe+0x61/0xc6
> [ 5714.314475] RIP: 0033:0x7ff766779b47
> [ 5714.318164] Code: 12 b8 03 00 00 00 0f 05 48 3d 00 f0 ff ff 77 3b c3 66
> 90 53 89 fb 48 83 ec 10 e8 e4 fb ff ff 89 df 89 c2 b8 03 00 00 00 0f 05 <48>
> 3d 00 f0 ff ff 77 2b 89 d7 89 44 24 0c e8 26 fc ff ff 8b 44 24
> [ 5714.337029] RSP: 002b:00007fff9058f3d0 EFLAGS: 00000293 ORIG_RAX:
> 0000000000000003
> [ 5714.344695] RAX: 0000000000000000 RBX: 0000000000000275 RCX:
> 00007ff766779b47
> [ 5714.351926] RDX: 0000000000000000 RSI: 00007ff766d870e0 RDI:
> 0000000000000275
> [ 5714.359156] RBP: 00007fff9058f400 R08: 0000000000000020 R09:
> 0000000000001a8c
> [ 5714.366387] R10: 00007fff9058ec48 R11: 0000000000000293 R12:
> 00007ff765fc4758
> [ 5714.373618] R13: 0000000000000029 R14: 00007ff765fc9528 R15:
> 0000619000000a80
> [ 5714.380851] ---[ end trace e6e6066ea7e090fa ]---
>