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charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 X-OriginatorOrg: hydroquebec.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: YT4PR01MB647290.CANPRD01.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-Network-Message-Id: 73ac1de8-1a11-431b-57ad-08df4185c5d4 X-MS-Exchange-CrossTenant-originalarrivaltime: 13 Nov 2026 12:58:11.5247 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: f40a10f0-50ee-4880-9a37-6e1dd4ac2ff3 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 00rL0V23iVJiQbTrGZjXd48EyQ/nCtPa6AQeieoJ3tmYw44zReLuyz7u3yXYLTMmjJtwJO3u94Hht4SWumXqTbiu+/gqZ1R3gx8S5z4536dY4lUGRwEHRLs7+IP50G1o X-MS-Exchange-Transport-CrossTenantHeadersStamped: YT4PR01MB815215 =0A= Hi,=0A= =0A= I posted v4 here:=0A= =0A= https://lore.kernel.org/all/20261112-ice-tx-hang-dump-v4-1-9125f687669b@hyd= roquebec.com/=0A= =0A= > Is pointer equality enough to show that this is still the hung ring?=0A= =0A= Pointer equality alone is not sufficient. In v4, the saved ring is used=0A= only if the timeout was on the PF VSI, that VSI is up, and=0A= vsi->tx_rings[queue] is the saved ring, with the queue recorded at timeout= =0A= time. PF VSI rings have q_index =3D=3D i, so a freed ring reused for anothe= r=0A= queue after ethtool -L is rejected and the dump falls back to the=0A= timeout-time values.=0A= =0A= A reset of the same queue in place is still not detected: ethtool -G=0A= replaces the ring contents, and ice_down() on an MTU change clears the=0A= descriptors and indices without changing desc. Comparing desc would=0A= miss the second case and is subject to address reuse. As before this=0A= patch, a successful snapshot shows the queue's ring when the report is=0A= generated. The v4 commit message and kernel-doc say so and no longer=0A= imply that ring replacement is detected.=0A= =0A= > Could the success path of ice_tx_hang_snapshot() at least set=0A= > ev->queue =3D tx_ring->q_index, the same way it updates next_to_clean=0A= > and next_to_use?=0A= =0A= With the check above, a successful snapshot comes from=0A= vsi->tx_rings[ev->queue], so there is no need to update ev->queue on the=0A= success path.=0A= =0A= In v4, I also read the saved ring pointer before taking RTNL,=0A= alongside queue, head and intr. This avoids reading the ring pointer=0A= after waiting for RTNL while using event values read before the wait.=0A= It does not make the event snapshot atomic; the handoff remains=0A= unsynchronized.=0A= =0A= > Could the commit message say whether removing the unused export is=0A= > planned as a net-next follow-up?=0A= =0A= Yes. The v4 commit message says so. I plan to send the removal of=0A= devlink_fmsg_dump_skb() to net-next once this fix is applied.=0A= =0A= > [High] This problem wasn't introduced by this patch, but the service=0A= > task can still run ice_report_tx_hang() during driver removal=0A= =0A= > [High] This problem wasn't introduced by this patch, but devlink reload= =0A= > with DRIVER_REINIT can deadlock=0A= =0A= Both issues predate this patch and are documented under Limitations=0A= in the v4 notes. =0A= I suggest addressing them in separate fixes to keep this patch focused. If = =0A= someone more familiar with these lifecycle and locking paths would like =0A= to take them on, that would be welcome.=0A= =0A= Thanks,=0A= Vincent=0A= =0A= pw-bot: cr=0A=