* [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support [not found] <20260413094442.1376022-1-hawk@kernel.org> @ 2026-04-13 19:49 ` syzbot ci 2026-04-14 8:06 ` Jesper Dangaard Brouer ` (2 more replies) 0 siblings, 3 replies; 7+ messages in thread From: syzbot ci @ 2026-04-13 19:49 UTC (permalink / raw) To: andrew, ast, bpf, corbet, daniel, davem, edumazet, frederic, hawk, horms, j.koeppeler, jhs, jiri, john.fastabend, kernel-team, krikku, kuba, kuniyu, linux-doc, linux-kernel, linux-kselftest, netdev, pabeni, sdf, shuah, skhan, yajun.deng Cc: syzbot, syzkaller-bugs syzbot ci has tested the following series [v2] veth: add Byte Queue Limits (BQL) support https://lore.kernel.org/all/20260413094442.1376022-1-hawk@kernel.org * [PATCH net-next v2 1/5] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices * [PATCH net-next v2 2/5] veth: implement Byte Queue Limits (BQL) for latency reduction * [PATCH net-next v2 3/5] veth: add tx_timeout watchdog as BQL safety net * [PATCH net-next v2 4/5] net: sched: add timeout count to NETDEV WATCHDOG message * [PATCH net-next v2 5/5] selftests: net: add veth BQL stress test and found the following issue: WARNING in veth_napi_del_range Full report is available here: https://ci.syzbot.org/series/ee732006-8545-4abd-a105-b4b1592a7baf *** WARNING in veth_napi_del_range tree: net-next URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net-next.git base: 8806d502e0a7e7d895b74afbd24e8550a65a2b17 arch: amd64 compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 config: https://ci.syzbot.org/builds/90743a26-f003-44cf-abcc-5991c47588b2/config syz repro: https://ci.syzbot.org/findings/d068bfb2-9f8b-466a-95b4-cd7e7b00006c/syz_repro ------------[ cut here ]------------ index >= dev->num_tx_queues WARNING: ./include/linux/netdevice.h:2672 at netdev_get_tx_queue include/linux/netdevice.h:2672 [inline], CPU#0: syz.1.27/6002 WARNING: ./include/linux/netdevice.h:2672 at veth_napi_del_range+0x3b7/0x4e0 drivers/net/veth.c:1142, CPU#0: syz.1.27/6002 Modules linked in: CPU: 0 UID: 0 PID: 6002 Comm: syz.1.27 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 RIP: 0010:netdev_get_tx_queue include/linux/netdevice.h:2672 [inline] RIP: 0010:veth_napi_del_range+0x3b7/0x4e0 drivers/net/veth.c:1142 Code: 00 e8 ad 96 69 fe 44 39 6c 24 10 74 5e e8 41 61 44 fb 41 ff c5 49 bc 00 00 00 00 00 fc ff df e9 6d ff ff ff e8 2a 61 44 fb 90 <0f> 0b 90 42 80 3c 23 00 75 8e eb 94 48 8b 0c 24 80 e1 07 80 c1 03 RSP: 0018:ffffc90003adf918 EFLAGS: 00010293 RAX: ffffffff86814ec6 RBX: 1ffff110227a6c03 RCX: ffff888103a857c0 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002 RBP: 1ffff110227a6c9a R08: ffff888113f01ab7 R09: 0000000000000000 R10: ffff888113f01a98 R11: ffffed10227e0357 R12: dffffc0000000000 R13: 0000000000000002 R14: 0000000000000002 R15: ffff888113d36018 FS: 000055555ea16500(0000) GS:ffff88818de4a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007efc287456b8 CR3: 000000010cdd0000 CR4: 00000000000006f0 Call Trace: <TASK> veth_napi_del drivers/net/veth.c:1153 [inline] veth_disable_xdp+0x1b0/0x310 drivers/net/veth.c:1255 veth_xdp_set drivers/net/veth.c:1693 [inline] veth_xdp+0x48e/0x730 drivers/net/veth.c:1717 dev_xdp_propagate+0x125/0x260 net/core/dev_api.c:348 bond_xdp_set drivers/net/bonding/bond_main.c:5715 [inline] bond_xdp+0x3ca/0x830 drivers/net/bonding/bond_main.c:5761 dev_xdp_install+0x42c/0x600 net/core/dev.c:10387 dev_xdp_detach_link net/core/dev.c:10579 [inline] bpf_xdp_link_release+0x362/0x540 net/core/dev.c:10595 bpf_link_free+0x103/0x480 kernel/bpf/syscall.c:3292 bpf_link_put_direct kernel/bpf/syscall.c:3344 [inline] bpf_link_release+0x6b/0x80 kernel/bpf/syscall.c:3351 __fput+0x44f/0xa70 fs/file_table.c:469 task_work_run+0x1d9/0x270 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:67 [inline] exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5bda39c819 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffdca2969e8 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f5bda617da0 RCX: 00007f5bda39c819 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f5bda617da0 R08: 00007f5bda616128 R09: 0000000000000000 R10: 000000000003fd78 R11: 0000000000000246 R12: 0000000000010fb8 R13: 00007f5bda61609c R14: 0000000000010cdd R15: 00007ffdca296af0 </TASK> *** If these findings have caused you to resend the series or submit a separate fix, please add the following tag to your commit message: Tested-by: syzbot@syzkaller.appspotmail.com --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. To test a patch for this bug, please reply with `#syz test` (should be on a separate line). The patch should be attached to the email. Note: arguments like custom git repos and branches are not supported. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support 2026-04-13 19:49 ` [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support syzbot ci @ 2026-04-14 8:06 ` Jesper Dangaard Brouer 2026-04-14 8:08 ` syzbot ci 2026-04-14 8:33 ` Aleksandr Nogikh 2026-04-15 13:05 ` Aleksandr Nogikh 2 siblings, 1 reply; 7+ messages in thread From: Jesper Dangaard Brouer @ 2026-04-14 8:06 UTC (permalink / raw) To: syzbot ci, andrew, ast, bpf, corbet, daniel, davem, edumazet, frederic, horms, j.koeppeler, john.fastabend, kernel-team, kuba, linux-doc, linux-kernel, linux-kselftest, netdev, pabeni, sdf, shuah Cc: syzbot, syzkaller-bugs [-- Attachment #1: Type: text/plain, Size: 4594 bytes --] On 13/04/2026 21.49, syzbot ci wrote: > syzbot ci has tested the following series > > [v2] veth: add Byte Queue Limits (BQL) support > https://lore.kernel.org/all/20260413094442.1376022-1-hawk@kernel.org > * [PATCH net-next v2 1/5] net: add dev->bql flag to allow BQL sysfs for IFF_NO_QUEUE devices > * [PATCH net-next v2 2/5] veth: implement Byte Queue Limits (BQL) for latency reduction > * [PATCH net-next v2 3/5] veth: add tx_timeout watchdog as BQL safety net > * [PATCH net-next v2 4/5] net: sched: add timeout count to NETDEV WATCHDOG message > * [PATCH net-next v2 5/5] selftests: net: add veth BQL stress test > > and found the following issue: > WARNING in veth_napi_del_range > > Full report is available here: > https://ci.syzbot.org/series/ee732006-8545-4abd-a105-b4b1592a7baf > > *** > > WARNING in veth_napi_del_range > Attached a reproducer myself. - I have V3 ready see below for diff > tree: net-next > URL: https://kernel.googlesource.com/pub/scm/linux/kernel/git/netdev/net-next.git > base: 8806d502e0a7e7d895b74afbd24e8550a65a2b17 > arch: amd64 > compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 > config: https://ci.syzbot.org/builds/90743a26-f003-44cf-abcc-5991c47588b2/config > syz repro: https://ci.syzbot.org/findings/d068bfb2-9f8b-466a-95b4-cd7e7b00006c/syz_repro > > ------------[ cut here ]------------ > index >= dev->num_tx_queues > WARNING: ./include/linux/netdevice.h:2672 at netdev_get_tx_queue include/linux/netdevice.h:2672 [inline], CPU#0: syz.1.27/6002 > WARNING: ./include/linux/netdevice.h:2672 at veth_napi_del_range+0x3b7/0x4e0 drivers/net/veth.c:1142, CPU#0: syz.1.27/6002 > Modules linked in: > CPU: 0 UID: 0 PID: 6002 Comm: syz.1.27 Not tainted syzkaller #0 PREEMPT(full) > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014 > RIP: 0010:netdev_get_tx_queue include/linux/netdevice.h:2672 [inline] > RIP: 0010:veth_napi_del_range+0x3b7/0x4e0 drivers/net/veth.c:1142 > Code: 00 e8 ad 96 69 fe 44 39 6c 24 10 74 5e e8 41 61 44 fb 41 ff c5 49 bc 00 00 00 00 00 fc ff df e9 6d ff ff ff e8 2a 61 44 fb 90 <0f> 0b 90 42 80 3c 23 00 75 8e eb 94 48 8b 0c 24 80 e1 07 80 c1 03 > RSP: 0018:ffffc90003adf918 EFLAGS: 00010293 > RAX: ffffffff86814ec6 RBX: 1ffff110227a6c03 RCX: ffff888103a857c0 > RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000000000002 > RBP: 1ffff110227a6c9a R08: ffff888113f01ab7 R09: 0000000000000000 > R10: ffff888113f01a98 R11: ffffed10227e0357 R12: dffffc0000000000 > R13: 0000000000000002 R14: 0000000000000002 R15: ffff888113d36018 > FS: 000055555ea16500(0000) GS:ffff88818de4a000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 00007efc287456b8 CR3: 000000010cdd0000 CR4: 00000000000006f0 > Call Trace: > <TASK> > veth_napi_del drivers/net/veth.c:1153 [inline] > veth_disable_xdp+0x1b0/0x310 drivers/net/veth.c:1255 > veth_xdp_set drivers/net/veth.c:1693 [inline] > veth_xdp+0x48e/0x730 drivers/net/veth.c:1717 > dev_xdp_propagate+0x125/0x260 net/core/dev_api.c:348 > bond_xdp_set drivers/net/bonding/bond_main.c:5715 [inline] > bond_xdp+0x3ca/0x830 drivers/net/bonding/bond_main.c:5761 > dev_xdp_install+0x42c/0x600 net/core/dev.c:10387 > dev_xdp_detach_link net/core/dev.c:10579 [inline] > bpf_xdp_link_release+0x362/0x540 net/core/dev.c:10595 > bpf_link_free+0x103/0x480 kernel/bpf/syscall.c:3292 > bpf_link_put_direct kernel/bpf/syscall.c:3344 [inline] > bpf_link_release+0x6b/0x80 kernel/bpf/syscall.c:3351 > __fput+0x44f/0xa70 fs/file_table.c:469 > task_work_run+0x1d9/0x270 kernel/task_work.c:233 The BQL reset loop in veth_napi_del_range() iterates dev->real_num_rx_queues but indexes into peer's TX queues, which goes out of bounds when the peer has fewer TX queues (e.g. veth enslaved to a bond with XDP). Fix is to clamp the loop to the peer's real_num_tx_queues. Will be included in the V3 submission. #syz test --- drivers/net/veth.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 911e7e36e166..9d7b085c9548 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1138,7 +1138,9 @@ static void veth_napi_del_range(struct net_device *dev, int start, int end) */ peer = rtnl_dereference(priv->peer); if (peer) { - for (i = start; i < end; i++) + int peer_end = min(end, (int)peer->real_num_tx_queues); + + for (i = start; i < peer_end; i++) netdev_tx_reset_queue(netdev_get_tx_queue(peer, i)); } [-- Attachment #2: repro-syzbot-veth-bql.sh --] [-- Type: application/x-shellscript, Size: 2967 bytes --] ^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: Re: [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support 2026-04-14 8:06 ` Jesper Dangaard Brouer @ 2026-04-14 8:08 ` syzbot ci 0 siblings, 0 replies; 7+ messages in thread From: syzbot ci @ 2026-04-14 8:08 UTC (permalink / raw) To: hawk Cc: andrew, ast, bpf, corbet, daniel, davem, edumazet, frederic, hawk, horms, j.koeppeler, john.fastabend, kernel-team, kuba, linux-doc, linux-kernel, linux-kselftest, netdev, pabeni, sdf, shuah, syzbot, syzkaller-bugs Please attach the patch to act upon. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support 2026-04-13 19:49 ` [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support syzbot ci 2026-04-14 8:06 ` Jesper Dangaard Brouer @ 2026-04-14 8:33 ` Aleksandr Nogikh 2026-04-14 17:05 ` syzbot ci 2026-04-15 13:05 ` Aleksandr Nogikh 2 siblings, 1 reply; 7+ messages in thread From: Aleksandr Nogikh @ 2026-04-14 8:33 UTC (permalink / raw) To: syzbot+cib904ea9ebb647254, hawk Cc: netdev, linux-kernel, syzkaller-bugs, syzbot (forgotten to Cc the right list) Hmm, just fixed a problem that may have affected `syz test` processing, let's try again: #syz test --- drivers/net/veth.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 911e7e36e166..9d7b085c9548 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1138,7 +1138,9 @@ static void veth_napi_del_range(struct net_device *dev, int start, int end) */ peer = rtnl_dereference(priv->peer); if (peer) { - for (i = start; i < end; i++) + int peer_end = min(end, (int)peer->real_num_tx_queues); + + for (i = start; i < peer_end; i++) netdev_tx_reset_queue(netdev_get_tx_queue(peer, i)); } ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support 2026-04-14 8:33 ` Aleksandr Nogikh @ 2026-04-14 17:05 ` syzbot ci 0 siblings, 0 replies; 7+ messages in thread From: syzbot ci @ 2026-04-14 17:05 UTC (permalink / raw) To: nogikh, hawk, linux-kernel, netdev, syzbot, syzkaller-bugs Cc: syzbot, syzkaller-bugs syzbot ci has tested the suggested fix patch on top of the following series: [v2] veth: add Byte Queue Limits (BQL) support https://lore.kernel.org/all/20260413094442.1376022-1-hawk@kernel.org Patch: https://ci.syzbot.org/jobs/bf27b11f-8196-4c99-bc10-11843ded8a31/patch The patch testing request could not be completed: tree "net-next" is no longer known Full report is available here: https://ci.syzbot.org/session/31e795da-e7ea-4f46-8412-c30d420a5f1e --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support 2026-04-13 19:49 ` [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support syzbot ci 2026-04-14 8:06 ` Jesper Dangaard Brouer 2026-04-14 8:33 ` Aleksandr Nogikh @ 2026-04-15 13:05 ` Aleksandr Nogikh 2026-04-15 16:22 ` syzbot ci 2 siblings, 1 reply; 7+ messages in thread From: Aleksandr Nogikh @ 2026-04-15 13:05 UTC (permalink / raw) To: syzbot+cib904ea9ebb647254, hawk Cc: netdev, linux-kernel, syzkaller-bugs, syzbot ... okay, one more fixed bug, one more try. #syz test --- drivers/net/veth.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 911e7e36e166..9d7b085c9548 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1138,7 +1138,9 @@ static void veth_napi_del_range(struct net_device *dev, int start, int end) */ peer = rtnl_dereference(priv->peer); if (peer) { - for (i = start; i < end; i++) + int peer_end = min(end, (int)peer->real_num_tx_queues); + + for (i = start; i < peer_end; i++) netdev_tx_reset_queue(netdev_get_tx_queue(peer, i)); } ^ permalink raw reply related [flat|nested] 7+ messages in thread
* [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support 2026-04-15 13:05 ` Aleksandr Nogikh @ 2026-04-15 16:22 ` syzbot ci 0 siblings, 0 replies; 7+ messages in thread From: syzbot ci @ 2026-04-15 16:22 UTC (permalink / raw) To: nogikh, hawk, linux-kernel, netdev, syzbot, syzkaller-bugs Cc: syzbot, syzkaller-bugs syzbot ci has tested the suggested fix patch on top of the following series: [v2] veth: add Byte Queue Limits (BQL) support https://lore.kernel.org/all/20260413094442.1376022-1-hawk@kernel.org Patch: https://ci.syzbot.org/jobs/4a19c4e7-8505-49e5-b80f-6107406612b0/patch The patch testing request could not be completed: Testing failed due to an infrastructure error. Testing results: * [build 0] Build Patched: error Full report is available here: https://ci.syzbot.org/session/67022682-86d9-4483-a528-4d95990f8038 --- This report is generated by a bot. It may contain errors. syzbot ci engineers can be reached at syzkaller@googlegroups.com. ^ permalink raw reply [flat|nested] 7+ messages in thread
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[not found] <20260413094442.1376022-1-hawk@kernel.org>
2026-04-13 19:49 ` [syzbot ci] Re: veth: add Byte Queue Limits (BQL) support syzbot ci
2026-04-14 8:06 ` Jesper Dangaard Brouer
2026-04-14 8:08 ` syzbot ci
2026-04-14 8:33 ` Aleksandr Nogikh
2026-04-14 17:05 ` syzbot ci
2026-04-15 13:05 ` Aleksandr Nogikh
2026-04-15 16:22 ` syzbot ci
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