[Bug 2129580] Re: [questing] kernel BUG at lib/string_helpers.c:1043!

Frode Nordahl 2129580 at bugs.launchpad.net
Wed Oct 29 00:28:58 UTC 2025


$ git bisect bad
34451f435c99988c2b02ab24c591db4a0315c495 is the first bad commit
commit 34451f435c99988c2b02ab24c591db4a0315c495 (HEAD)
Author: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
Date:   Tue Aug 5 14:38:08 2025 +0200

    fs: always return zero on success from replace_fd()

    commit 708c04a5c2b78e22f56e2350de41feba74dfccd9 upstream.

    replace_fd() returns the number of the new file descriptor through the
    return value of do_dup2(). However its callers never care about the
    specific returned number. In fact the caller in receive_fd_replace() treats
    any non-zero return value as an error and therefore never calls
    __receive_sock() for most file descriptors, which is a bug.

    To fix the bug in receive_fd_replace() and to avoid the same issue
    happening in future callers, signal success through a plain zero.

    Suggested-by: Al Viro <viro at zeniv.linux.org.uk>
    Link: https://lore.kernel.org/lkml/20250801220215.GS222315@ZenIV/
    Fixes: 173817151b15 ("fs: Expand __receive_fd() to accept existing fd")
    Fixes: 42eb0d54c08a ("fs: split receive_fd_replace from __receive_fd")
    Cc: stable at vger.kernel.org
    Signed-off-by: Thomas Weißschuh <thomas.weissschuh at linutronix.de>
    Link: https://lore.kernel.org/20250805-fix-receive_fd_replace-v3-1-b72ba8b34bac@linutronix.de
    Signed-off-by: Christian Brauner <brauner at kernel.org>
    Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>

 fs/file.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)


** Changed in: linux (Ubuntu)
       Status: Incomplete => New

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https://bugs.launchpad.net/bugs/2129580

Title:
  [questing] kernel BUG at lib/string_helpers.c:1043!

Status in linux package in Ubuntu:
  New
Status in openvswitch package in Ubuntu:
  New

Bug description:
  Steps to reproduce the issue:
  1. sudo apt build-dep openvswitch
  2. git clone https://github.com/openvswitch/ovs.git
  3. cd ovs
  4. ./boot.sh && ./configure && make -j$(nproc)
  5. sudo make check-kernel TESTSUITEFLAGS="-j1 18"

  [  113.572334] kernel BUG at lib/string_helpers.c:1043!
  [  113.574460] Oops: invalid opcode: 0000 [#1] SMP NOPTI
  [  113.576569] CPU: 28 UID: 0 PID: 621 Comm: kworker/28:2 Tainted: G        W           6.17.0-6-generic #6-Ubuntu PREEMPT(voluntary) 
  [  113.585277] Tainted: [W]=WARN
  [  113.586715] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009)/LXD, BIOS unknown 2/2/2022
  [  113.590549] Workqueue: mld mld_ifc_work
  [  113.592104] RIP: 0010:__fortify_panic+0xd/0xf
  [  113.593853] Code: e9 12 8f 9c 00 e9 38 8f 9c 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 40 0f b6 ff 48 89 e5 e8 93 a8 9c 00 <0f> 0b 48 8b 95 28 ff ff ff 48 8b b5 30 ff ff ff 4c 89 e9 48 c7 c7
  [  113.601212] RSP: 0018:ffffd16440870bb0 EFLAGS: 00010246
  [  113.603298] RAX: 0000000000000000 RBX: ffff8be7c788b600 RCX: 0000000000000000
  [  113.606140] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
  [  113.609031] RBP: ffffd16440870bb0 R08: 0000000000000000 R09: 0000000000000000
  [  113.611856] R10: 0000000000000000 R11: 0000000000000000 R12: ffffd16440870c38
  [  113.614690] R13: 0000000000000004 R14: 0000000000000001 R15: ffff8be7ef7e1a80
  [  113.617556] FS:  0000000000000000(0000) GS:ffff8bef6dc7f000(0000) knlGS:0000000000000000
  [  113.620752] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [  113.623048] CR2: 00007ef5f13e0c47 CR3: 0000000509840000 CR4: 0000000000350ef0
  [  113.625880] Call Trace:
  [  113.626883]  <IRQ>
  [  113.627725]  erspan_rcv.cold+0x68/0x83 [ip_gre]
  [  113.629547]  ? ip_route_input_slow+0x816/0x9d0
  [  113.631334]  gre_rcv+0x1b2/0x1c0 [ip_gre]
  [  113.632949]  gre_rcv+0x8e/0x100 [gre]
  [  113.634428]  ? raw_v4_input+0x250/0x280
  [  113.635974]  ip_protocol_deliver_rcu+0x1ea/0x210
  [  113.637830]  ip_local_deliver_finish+0x86/0x110
  [  113.639699]  ip_local_deliver+0x65/0x110
  [  113.641285]  ? ip_rcv_finish_core+0xd6/0x370
  [  113.643010]  ip_rcv+0x186/0x1a0
  [  113.644287]  __netif_receive_skb_one_core+0x8d/0xa0
  [  113.646246]  __netif_receive_skb+0x16/0x70
  [  113.647891]  ? _raw_spin_unlock_irq+0xe/0x60
  [  113.649616]  process_backlog+0x90/0x160
  [  113.651163]  __napi_poll+0x35/0x200
  [  113.652576]  net_rx_action+0x20b/0x3f0
  [  113.654087]  ? __run_timers+0x1c8/0x2c0
  [  113.655635]  handle_softirqs+0xdf/0x330
  [  113.657183]  __do_softirq+0x10/0x18
  [  113.658604]  do_softirq.part.0+0x3f/0x80
  [  113.660182]  </IRQ>
  [  113.661051]  <TASK>
  [  113.661914]  __local_bh_enable_ip+0x6a/0x70
  [  113.663598]  __dev_queue_xmit+0x44f/0x850
  [  113.665211]  ? __kmalloc_noprof+0x2b8/0x580
  [  113.666885]  ? ndisc_mc_map+0x41/0xe0
  [  113.668411]  ? ndisc_constructor+0x1f6/0x3f0
  [  113.670424]  ? _raw_write_unlock_bh+0x1a/0x30
  [  113.672456]  ? ___neigh_create+0x755/0x9d0
  [  113.674378]  neigh_resolve_output+0x122/0x200
  [  113.676402]  ip6_finish_output2+0x212/0x620
  [  113.678349]  ? __kmalloc_node_track_caller_noprof+0x282/0x5a0
  [  113.680904]  ? __alloc_skb+0x87/0x1b0
  [  113.682635]  ? sched_balance_rq+0x100/0x9c0
  [  113.684567]  ip6_finish_output+0x1ea/0x4a0
  [  113.686461]  ? nf_hook_slow+0x48/0x120
  [  113.688225]  ip6_output+0x75/0x1b0
  [  113.689834]  ? __pfx_ip6_finish_output+0x10/0x10
  [  113.691914]  NF_HOOK.constprop.0+0x4e/0x130
  [  113.693696]  ? xfrm_lookup+0x11/0x30
  [  113.695013]  ? icmp6_dst_alloc+0x16f/0x230
  [  113.696486]  mld_sendpack+0x196/0x270
  [  113.697832]  mld_send_cr+0x2c1/0x340
  [  113.699220]  mld_ifc_work+0x32/0x170
  [  113.700530]  process_one_work+0x18e/0x370
  [  113.701983]  worker_thread+0x317/0x450
  [  113.703345]  ? _raw_spin_unlock_irqrestore+0x11/0x60
  [  113.705086]  ? __pfx_worker_thread+0x10/0x10
  [  113.706598]  kthread+0x10b/0x220
  [  113.707795]  ? _raw_spin_unlock_irq+0xe/0x60
  [  113.709317]  ? __pfx_kthread+0x10/0x10
  [  113.710670]  ret_from_fork+0x134/0x150
  [  113.712030]  ? __pfx_kthread+0x10/0x10
  [  113.713378]  ret_from_fork_asm+0x1a/0x30
  [  113.714786]  </TASK>
  [  113.715655] Modules linked in: vport_vxlan vxlan vport_gre ip_gre vport_geneve geneve openvswitch ip6_gre ip6_tunnel tunnel6 bonding tls 8021q garp mrp stp llc veth nfnetlink_cttimeout ip_tunnel gre ip6_udp_tunnel udp_tunnel nsh nf_conncount nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 psample qrtr cfg80211 binfmt_misc nls_iso8859_1 intel_rapl_msr intel_rapl_common kvm_amd ccp 9pnet_virtio 9pnet kvm netfs virtiofs irqbypass i2c_i801 i2c_smbus lpc_ich vmw_vsock_virtio_transport virtio_input i2c_mux vmgenid joydev input_leds mac_hid sch_fq_codel msr efi_pstore dm_multipath nfnetlink vsock_loopback vmw_vsock_virtio_transport_common vmw_vsock_vmci_transport vsock vmw_vmci dmi_sysfs qemu_fw_cfg ip_tables x_tables autofs4 btrfs blake2b_generic raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq raid1 raid0 linear polyval_clmulni psmouse ahci virtio_gpu ghash_clmulni_intel serio_raw libahci virtio_dma_buf virtio_rng aesni_intel [last unloaded: geneve]
  [  113.744262] ---[ end trace 0000000000000000 ]---
  [  115.172377] RIP: 0010:__fortify_panic+0xd/0xf
  [  115.178114] Code: e9 12 8f 9c 00 e9 38 8f 9c 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 55 40 0f b6 ff 48 89 e5 e8 93 a8 9c 00 <0f> 0b 48 8b 95 28 ff ff ff 48 8b b5 30 ff ff ff 4c 89 e9 48 c7 c7
  [  115.186507] RSP: 0018:ffffd16440870bb0 EFLAGS: 00010246
  [  115.188985] RAX: 0000000000000000 RBX: ffff8be7c788b600 RCX: 0000000000000000
  [  115.192253] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
  [  115.195447] RBP: ffffd16440870bb0 R08: 0000000000000000 R09: 0000000000000000
  [  115.198650] R10: 0000000000000000 R11: 0000000000000000 R12: ffffd16440870c38
  [  115.201849] R13: 0000000000000004 R14: 0000000000000001 R15: ffff8be7ef7e1a80
  [  115.205063] FS:  0000000000000000(0000) GS:ffff8bef6dc7f000(0000) knlGS:0000000000000000
  [  115.208651] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [  115.211321] CR2: 00007ef5f13e0c47 CR3: 0000000509840000 CR4: 0000000000350ef0
  [  115.214550] Kernel panic - not syncing: Fatal exception in interrupt
  [  115.217563] Kernel Offset: 0x2ce00000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
  [  116.452155] ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---

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