* Re: [RFC net v4 0/4] bnxt_en: Make RING FREE more robust
@ 2026-10-06 16:43 anmory
2026-10-06 20:00 ` Joe Damato
2026-10-06 20:22 ` Joe Damato
0 siblings, 2 replies; 6+ messages in thread
From: anmory @ 2026-10-06 16:43 UTC (permalink / raw)
To: joe; +Cc: netdev, michael.chan, pavan.chebbi, linux-kernel
[-- Attachment #1.1: Type: text/plain, Size: 2671 bytes --]
Hi Joe,
we appear to be hitting a very similar issue to the one described in
this RFC on two Broadcom BCM57504 systems.
One detail that may be particularly relevant is the ordering in our
reproductions: on both systems the AMD-Vi IO_PAGE_FAULT occurs before
the NETDEV WATCHDOG / TX timeout.
We originally encountered the problem after updating from Debian
6.12.107-1 to 6.12.111-1.
We subsequently reproduced it deliberately on two separate systems.
Test results:
affected-host-1:
BCM57504 [14e4:1751], bnxt_en
BIOS: 1.16.2
NIC FW: 36.11.55.00
FW mgmt: 236.1.153.0
6.12.107-1: stable
6.12.111-1: failure reproduced
affected-host-2:
BCM57504 [14e4:1751], bnxt_en
BIOS: 1.18.2
NIC FW: 36.11.73.00
FW mgmt: 236.1.173.0
6.12.107-1: stable
6.12.111-1: failure reproduced
The failure sequence on affected-host-1 was:
06:49:00 AMD-Vi IO_PAGE_FAULT
06:49:14 NETDEV WATCHDOG: transmit queue 0 timed out
06:49:14 TX timeout detected, starting reset task
06:49:18 HWRM/RING_FREE failures begin
06:49:25 HWRM_RING_ALLOC fails
06:49:25 bnxt_init_nic fails
06:49:25 nic open fails
On affected-host-2:
15:29:09 AMD-Vi IO_PAGE_FAULT
15:29:15 NETDEV WATCHDOG: transmit queue 4 timed out
15:29:15 TX timeout detected, starting reset task
15:29:19 HWRM/RING_FREE failures begin
15:29:37 HWRM_RING_ALLOC fails
15:29:37 bnxt_init_nic fails
15:29:37 nic open fails
So in our reproductions the IOMMU fault precedes the TX watchdog by
approximately 6-14 seconds.
We have also observed the timeout on different TX queues across
different occurrences, so it does not appear to be tied to a specific
queue.
Both interfaces were up and operating at 25 Gbit/s before the failure.
The systems use the IOMMU in translated mode.
After the reset attempt fails, the interface cannot be reopened and a
reboot is required.
The same problem therefore reproduces across:
- two physical systems
- two BIOS revisions
- two NIC firmware revisions
- different TX queues
while reverting to 6.12.107-1 has been stable with the same workload.
I've attached sanitized diagnostic output from both reproductions,
including PCI/device information, firmware versions, IOMMU
configuration and the complete failure event sequence.
We have not bisected the changes between 6.12.107 and 6.12.111 yet.
Given that the IO_PAGE_FAULT precedes the watchdog in our case, I
wonder whether this may provide some information about the initial
failure, in addition to the RING_FREE recovery problem addressed by
your RFC.
Please let me know if there are additional diagnostics that would be
useful, or if you would like us to test the RFC series on one of these
systems.
Thanks,
R.
https://proton.me/mail/home
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=== SYSTEM ===
hostname: affected-host-1
bios_version: 1.16.2
bios_date: 01/16/2026
eth1_pci_device: 0000:c4:00.2
=== NIC / DRIVER ===
c4:00.2 Ethernet controller [0200]: Broadcom Inc. and subsidiaries BCM57504 NetXtreme-E 10Gb/25Gb/40Gb/50Gb/100Gb Ethernet [14e4:1751] (rev 12)
DeviceName: Integrated NIC 1 Port 3-1
Subsystem: Broadcom Inc. and subsidiaries NetXtreme-E BCM57504 4x25G OCP3.0 [14e4:5045]
Kernel driver in use: bnxt_en
Kernel modules: bnxt_en
=== DEVLINK ===
pci/0000:c4:00.2:
driver bnxt_en
serial_number <redacted>
versions:
fixed:
board.id BCM957504
asic.id 1751
asic.rev B2
running:
fw.psid 232.0.2
fw 36.11.55.00
fw.mgmt 236.1.153.0
fw.mgmt.api 1.10.3
stored:
fw.psid 232.0.2
fw 36.11.55.00
fw.mgmt 236.1.153.0
=== CAPTURE BASELINE ===
2026-10-06T06:28:26+00:00
affected-host-1
6.12.111+deb13-amd64
1.16.2
01/16/2026
eth1 UP XX:XX:XX:XX:XX:XX <BROADCAST,MULTICAST,UP,LOWER_UP>
=== RELEVANT BOOT / HARDWARE ===
2026-10-06T06:28:25+00:00 affected-host-1 kernel: Linux version 6.12.111+deb13-amd64 (debian-kernel@lists.debian.org) (x86_64-linux-gnu-gcc-14 (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44) #1 SMP PREEMPT_DYNAMIC Debian 6.12.111-1 (2026-09-28)
2026-10-06T06:28:25+00:00 affected-host-1 kernel: DMI: Dell Inc. PowerEdge R7615, BIOS 1.16.2 01/16/2026
2026-10-06T06:28:25+00:00 affected-host-1 kernel: pci 0000:c4:00.2: [14e4:1751] type 00 class 0x020000 PCIe Endpoint
2026-10-06T06:28:25+00:00 affected-host-1 kernel: iommu: Default domain type: Translated
2026-10-06T06:28:25+00:00 affected-host-1 kernel: iommu: DMA domain TLB invalidation policy: lazy mode
2026-10-06T06:28:25+00:00 affected-host-1 kernel: pci 0000:c4:00.2: Adding to iommu group 14
2026-10-06T06:28:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth4: Broadcom BCM57504 NetXtreme-E 10Gb/25Gb/50Gb/100Gb/200Gb Ethernet found at mem cb010000, node addr XX:XX:XX:XX:XX:XX
2026-10-06T06:28:26+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: NIC Link is Up, 25000 Mbps (NRZ) full duplex, Flow control: ON - receive & transmit
2026-10-06T06:28:26+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: FEC autoneg off encoding: Clause 74 BaseR
=== FAILURE EVENTS ===
2026-10-06T06:49:00+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x000f address=0xfb387000 flags=0x0000]
2026-10-06T06:49:14+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: NETDEV WATCHDOG: CPU: 2: transmit queue 0 timed out 5312 ms
2026-10-06T06:49:14+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: TX timeout detected, starting reset task!
2026-10-06T06:49:18+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T06:49:18+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: hwrm_ring_free type 1 failed. rc:fffffff0 err:2
2026-10-06T06:49:21+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T06:49:21+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: hwrm_ring_free type 2 failed. rc:fffffff0 err:0
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: hwrm_ring_free type 4 failed. rc:fffffff0 err:0
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: hwrm_ring_alloc type 1 failed. rc:ffffffe4 err:4
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: bnxt_init_nic err: fffffffb
2026-10-06T06:49:25+00:00 affected-host-1 kernel: bnxt_en 0000:c4:00.2 eth1: nic open fail (rc: fffffffb)
[-- Attachment #3: affected-host-2-bnxt.txt --]
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=== SYSTEM ===
hostname: affected-host-2
bios_version: 1.18.2
bios_date: 07/22/2026
eth1_pci_device: 0000:c4:00.3
=== NIC / DRIVER ===
c4:00.3 Ethernet controller [0200]: Broadcom Inc. and subsidiaries BCM57504 NetXtreme-E 10Gb/25Gb/40Gb/50Gb/100Gb Ethernet [14e4:1751] (rev 12)
DeviceName: Integrated NIC 1 Port 4-1
Subsystem: Broadcom Inc. and subsidiaries NetXtreme-E BCM57504 4x25G OCP3.0 [14e4:5045]
Kernel driver in use: bnxt_en
Kernel modules: bnxt_en
=== DEVLINK ===
pci/0000:c4:00.3:
driver bnxt_en
serial_number <redacted>
versions:
fixed:
board.id BCM957504
asic.id 1751
asic.rev B2
running:
fw.psid 232.0.2
fw 36.11.73.00
fw.mgmt 236.1.173.0
fw.mgmt.api 1.10.3
stored:
fw.psid 232.0.2
fw 36.11.73.00
fw.mgmt 236.1.173.0
=== CAPTURE BASELINE ===
2026-10-06T15:29:09+00:00
affected-host-2
6.12.111+deb13-amd64
1.18.2
07/22/2026
eth1 UP XX:XX:XX:XX:XX:XX <BROADCAST,MULTICAST,UP,LOWER_UP>
=== RELEVANT BOOT / HARDWARE ===
2026-10-06T15:29:07+00:00 affected-host-2 kernel: Linux version 6.12.111+deb13-amd64 (debian-kernel@lists.debian.org) (x86_64-linux-gnu-gcc-14 (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44) #1 SMP PREEMPT_DYNAMIC Debian 6.12.111-1 (2026-09-28)
2026-10-06T15:29:07+00:00 affected-host-2 kernel: DMI: Dell Inc. PowerEdge R7615, BIOS 1.18.2 07/22/2026
2026-10-06T15:29:07+00:00 affected-host-2 kernel: pci 0000:c4:00.3: [14e4:1751] type 00 class 0x020000 PCIe Endpoint
2026-10-06T15:29:07+00:00 affected-host-2 kernel: iommu: Default domain type: Translated
2026-10-06T15:29:07+00:00 affected-host-2 kernel: iommu: DMA domain TLB invalidation policy: lazy mode
2026-10-06T15:29:07+00:00 affected-host-2 kernel: pci 0000:c4:00.3: Adding to iommu group 15
2026-10-06T15:29:07+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth5: Broadcom BCM57504 NetXtreme-E 10Gb/25Gb/50Gb/100Gb/200Gb Ethernet found at mem cb000000, node addr XX:XX:XX:XX:XX:XX
2026-10-06T15:29:09+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: NIC Link is Up, 25000 Mbps (NRZ) full duplex, Flow control: ON - receive & transmit
2026-10-06T15:29:09+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: FEC autoneg off encoding: Clause 74 BaseR
=== FAILURE EVENTS ===
2026-10-06T15:29:09+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3: AMD-Vi: Event logged [IO_PAGE_FAULT domain=0x0010 address=0xfb526000 flags=0x0000]
2026-10-06T15:29:15+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: NETDEV WATCHDOG: CPU: 23: transmit queue 4 timed out 5628 ms
2026-10-06T15:29:15+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: TX timeout detected, starting reset task!
2026-10-06T15:29:19+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T15:29:19+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 1 failed. rc:fffffff0 err:0
2026-10-06T15:29:19+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 1 failed. rc:ffffffea err:2
2026-10-06T15:29:19+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 1 failed. rc:ffffffea err:2
2026-10-06T15:29:22+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T15:29:22+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 1 failed. rc:fffffff0 err:2
2026-10-06T15:29:22+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 1 failed. rc:ffffffea err:2
2026-10-06T15:29:26+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T15:29:26+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 2 failed. rc:fffffff0 err:0
2026-10-06T15:29:30+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T15:29:30+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 4 failed. rc:fffffff0 err:0
2026-10-06T15:29:33+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T15:29:33+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 2 failed. rc:fffffff0 err:0
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: Resp cmpl intr err msg: 0x51
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 4 failed. rc:fffffff0 err:0
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_free type 0 failed. rc:fffffffb err:1
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: hwrm_ring_alloc type 1 failed. rc:ffffffe4 err:4
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: bnxt_init_nic err: fffffffb
2026-10-06T15:29:37+00:00 affected-host-2 kernel: bnxt_en 0000:c4:00.3 eth1: nic open fail (rc: fffffffb)
^ permalink raw reply [flat|nested] 6+ messages in thread* Re: [RFC net v4 0/4] bnxt_en: Make RING FREE more robust
2026-10-06 16:43 [RFC net v4 0/4] bnxt_en: Make RING FREE more robust anmory
@ 2026-10-06 20:00 ` Joe Damato
2026-10-06 20:22 ` Joe Damato
1 sibling, 0 replies; 6+ messages in thread
From: Joe Damato @ 2026-10-06 20:00 UTC (permalink / raw)
To: anmory; +Cc: netdev, michael.chan, pavan.chebbi, linux-kernel
On Tue, Oct 06, 2026 at 04:43:42PM +0000, anmory wrote:
> Hi Joe,
>
> we appear to be hitting a very similar issue to the one described in
> this RFC on two Broadcom BCM57504 systems.
>
> One detail that may be particularly relevant is the ordering in our
> reproductions: on both systems the AMD-Vi IO_PAGE_FAULT occurs before
> the NETDEV WATCHDOG / TX timeout.
>
> We originally encountered the problem after updating from Debian
> 6.12.107-1 to 6.12.111-1.
>
> We subsequently reproduced it deliberately on two separate systems.
Can you provide a sample program or explanation on how *exactly* to reproduce
this issue?
I've hit the same one you are describing (IO_PAGE_FAULT before the NETDEV TX
timeout) but have not been able to reliably reproduce it. It happens fairly
rarely on my systems, but I am very eager to debug this and fix it.
If you have a way to reliably reproduce this, that would make it *much* easier
to debug.
Thanks,
Joe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC net v4 0/4] bnxt_en: Make RING FREE more robust
2026-10-06 16:43 [RFC net v4 0/4] bnxt_en: Make RING FREE more robust anmory
2026-10-06 20:00 ` Joe Damato
@ 2026-10-06 20:22 ` Joe Damato
2026-10-06 22:22 ` anmory
1 sibling, 1 reply; 6+ messages in thread
From: Joe Damato @ 2026-10-06 20:22 UTC (permalink / raw)
To: anmory; +Cc: netdev, michael.chan, pavan.chebbi, linux-kernel
On Tue, Oct 06, 2026 at 04:43:42PM +0000, anmory wrote:
> Hi Joe,
>
> we appear to be hitting a very similar issue to the one described in
> this RFC on two Broadcom BCM57504 systems.
>
> One detail that may be particularly relevant is the ordering in our
> reproductions: on both systems the AMD-Vi IO_PAGE_FAULT occurs before
> the NETDEV WATCHDOG / TX timeout.
>
> We originally encountered the problem after updating from Debian
> 6.12.107-1 to 6.12.111-1.
BTW there was recently this patch [1] proposed by Eric which helps prevent
a bug Stefan reported [2].
I am not sure whether the bug you are hitting is Eric's bug or the bug I am
chasing.
Other than explaining how you repro'd the issue, if you want to test Eric's
patch you could apply his patch to v6.12.111 and see if the issue still
occurs.
If it stops, it's probably the bug Eric fixed and not the one I'm chasing :)
but if it continues, it could be what I've been looking for and I'd really
want to know how you reproduced it, please.
[1]: https://lore.kernel.org/netdev/20261006042153.199444-1-edumazet@kernel.org/
[2]: https://lore.kernel.org/netdev/20261004122616.56714cbd@nargothrond/
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC net v4 0/4] bnxt_en: Make RING FREE more robust
2026-10-06 20:22 ` Joe Damato
@ 2026-10-06 22:22 ` anmory
2026-10-06 22:37 ` Joe Damato
0 siblings, 1 reply; 6+ messages in thread
From: anmory @ 2026-10-06 22:22 UTC (permalink / raw)
To: Joe Damato; +Cc: netdev, michael.chan, pavan.chebbi, linux-kernel
Hi Joe,
one important detail I omitted from my previous mail: the affected eth1 interface is an 802.1Q trunk with multiple VLAN subinterfaces.
We also use Keepalived VRRP with use_vmac, so virtual MAC interfaces are layered on the VLAN interfaces. Traffic is routed/forwarded through the host and uses conntrack/SNAT before leaving through another physical interface.
We are not deliberately toggling VLAN offload during the test. The reproduction so far is simply to boot Debian 6.12.111-1 with this normal network configuration and workload. On one host it reproduced after about 20 minutes; on another it reproduced almost immediately. We have also seen a previous occurrence after several hours, so we do not yet have a deterministic packet-level trigger.
Given the VLAN configuration, Eric's patch looks especially relevant. I'll test 6.12.111 with that patch first as you suggested and report whether the failure still reproduces.
Thanks, R.
-------- Original Message --------
On Tuesday, 10/06/26 at 22:22 Joe Damato <joe@dama.to> wrote:
On Tue, Oct 06, 2026 at 04:43:42PM +0000, anmory wrote:
> Hi Joe,
>
> we appear to be hitting a very similar issue to the one described in
> this RFC on two Broadcom BCM57504 systems.
>
> One detail that may be particularly relevant is the ordering in our
> reproductions: on both systems the AMD-Vi IO_PAGE_FAULT occurs before
> the NETDEV WATCHDOG / TX timeout.
>
> We originally encountered the problem after updating from Debian
> 6.12.107-1 to 6.12.111-1.
BTW there was recently this patch [1] proposed by Eric which helps prevent
a bug Stefan reported [2].
I am not sure whether the bug you are hitting is Eric's bug or the bug I am
chasing.
Other than explaining how you repro'd the issue, if you want to test Eric's
patch you could apply his patch to v6.12.111 and see if the issue still
occurs.
If it stops, it's probably the bug Eric fixed and not the one I'm chasing :)
but if it continues, it could be what I've been looking for and I'd really
want to know how you reproduced it, please.
[1]: https://lore.kernel.org/netdev/20261006042153.199444-1-edumazet@kernel.org/
[2]: https://lore.kernel.org/netdev/20261004122616.56714cbd@nargothrond/
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [RFC net v4 0/4] bnxt_en: Make RING FREE more robust
2026-10-06 22:22 ` anmory
@ 2026-10-06 22:37 ` Joe Damato
0 siblings, 0 replies; 6+ messages in thread
From: Joe Damato @ 2026-10-06 22:37 UTC (permalink / raw)
To: anmory; +Cc: netdev, michael.chan, pavan.chebbi, linux-kernel
On Tue, Oct 06, 2026 at 10:22:51PM +0000, anmory wrote:
>
> Hi Joe,
> one important detail I omitted from my previous mail: the affected eth1 interface is an 802.1Q trunk with multiple VLAN subinterfaces.
> We also use Keepalived VRRP with use_vmac, so virtual MAC interfaces are layered on the VLAN interfaces. Traffic is routed/forwarded through the host and uses conntrack/SNAT before leaving through another physical interface.
> We are not deliberately toggling VLAN offload during the test. The reproduction so far is simply to boot Debian 6.12.111-1 with this normal network configuration and workload. On one host it reproduced after about 20 minutes; on another it reproduced almost immediately. We have also seen a previous occurrence after several hours, so we do not yet have a deterministic packet-level trigger.
> Given the VLAN configuration, Eric's patch looks especially relevant. I'll test 6.12.111 with that patch first as you suggested and report whether the failure still reproduces.
Seems likely you are hitting the bug Eric just fixed, IMHO. If his patch
resolves your issue, please let me know.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [RFC net v4 0/4] bnxt_en: Make RING FREE more robust
@ 2026-09-25 17:43 Joe Damato
0 siblings, 0 replies; 6+ messages in thread
From: Joe Damato @ 2026-09-25 17:43 UTC (permalink / raw)
To: netdev
Cc: andrew+netdev, davem, edumazet, kuba, pabeni, horms,
michael.chan, pavan.chebbi, linux-kernel, Joe Damato
Greetings:
This is a follow up to the previous RFC (linked below), updated based on
feedback from Michael.
On two production systems, I saw the following dmesg pattern:
NETDEV WATCHDOG: transmit queue 0 timed out 6073 ms
Resp cmpl intr err msg: 0x51 x20
hwrm_ring_free type 1 failed x12
hwrm_ring_free type 2 failed x8
AMD-Vi: IO_PAGE_FAULT x3
This suggests that, for some currently unknown reason, TX completions stall
and the netdev watchdog fires. The driver asks FW to free the rings, this
times out, but the driver ignores the possible failure and frees ring memory.
Since the FW didn't respond to the ring free command, it is possible that the
FW is still DMAing to the memory which was freed.
This series tries to prevent this by:
- Returning and checking ring free command return values
- Examining the FW response if the ring free command times out. It is
possible that, for some reason, the FW did complete the ring free but was
unable to respond with an IRQ. This seems unlikely given what appears to be
a use after free in dmesg, but worth logging just in case.
- Stop DMA before the driver frees ring memory, which should prevent
any possible use after free.
- Set a bit in the state flags to signal that DMA was stopped. This prevents
the device from being reopened without user intervention.
In the future, this could possibly be extended to make recovery automatic.
Sending this as an RFC so that the Broadcom folks have some time to take a
look and test as needed.
Thanks,
Joe
v4:
- No changes to patch 1 or 2
- Patch 3: reworded the message logged when DMA is stopped, a rebind is
what recovers the device, not a firmware reset. No functional change.
- Patch 4 added which adds a new bit (BNXT_STATE_DMA_STOPPED) that is set
when DMA is disabled. When this bit is set, the device requires user
intervention to bring back up.
v3: https://lore.kernel.org/netdev/20260923210744.3406861-1-joe@dama.to/
- No changes to patch 1
- Patch 2: Don't poll for the valid bit as Michael suggested.
- Patch 3: bnxt_hwrm_ring_free now returns -EIO instead of stopping the
device, so the remaining resources can be freed and the remaining commands
can be sent before stopping the device, as Michael suggested. Note the
switch to using pci_clear_master in this patch instead of
pci_disable_device. This was done so that the normal shutdown paths can
call pci_disable_device without generating a warning.
v2: https://lore.kernel.org/netdev/20260922182405.1290749-1-joe@dama.to/
- No changes to patch 1
- Patch 2 from v1 dropped
- Patch 2 in the v2 now checks the response and logs state before giving up
- Patch 3 in the v2 disables the device to stop DMA before freeing ring
memory
RFCv1: https://lore.kernel.org/netdev/20260917233218.1160001-1-joe@dama.to/
Joe Damato (4):
bnxt_en: return the RING_FREE status to callers
bnxt_en: check HWRM response if completion never arrives
bnxt_en: stop DMA before releasing rings the firmware did not free
bnxt_en: refuse to open a device with stopped DMA
drivers/net/ethernet/broadcom/bnxt/bnxt.c | 122 ++++++++++++------
drivers/net/ethernet/broadcom/bnxt/bnxt.h | 1 +
.../net/ethernet/broadcom/bnxt/bnxt_hwrm.c | 33 ++++-
3 files changed, 115 insertions(+), 41 deletions(-)
base-commit: 11536ee3d3e0b1bd35b6f3f8df55a6053eb0c71d
--
2.53.0-Meta
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-10-06 22:37 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2026-10-06 16:43 [RFC net v4 0/4] bnxt_en: Make RING FREE more robust anmory
2026-10-06 20:00 ` Joe Damato
2026-10-06 20:22 ` Joe Damato
2026-10-06 22:22 ` anmory
2026-10-06 22:37 ` Joe Damato
-- strict thread matches above, loose matches on Subject: below --
2026-09-25 17:43 Joe Damato
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