On 12/4/2025 11:48 AM, Gerd Bayer wrote:

On Wed, 2025-12-03 at 17:14 +0200, Moshe Shemesh wrote:

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On 12/2/2025 1:12 PM, Gerd Bayer wrote:

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   [ ... snip ... ]

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Fixes: 5a977b5833b7 ("net/mlx5: Lag, move devcom registration to LAG layer")
Signed-off-by: Gerd Bayer <gbayer@linux.ibm.com>

Reviewed-by: Moshe Shemesh <redacted>> ---

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Hi Shay et al,

Hi Gerd,
   I stepped on this bug recently too, without s390 and was about to
submit same fix :) So as you wrote it is unrelated to Lukas' patches and
this fix is correct.

Good to hear. I wonder if you could share how you got to run into this?

mlx5_unload_one() can be called from few flows.
Even that it is always called with devlink lock, serial of 
mlx5_unload_one() twice caused it. I got it on fw_reset and shutdown. I 
I will submit also a patch for calling mlx5_drain_fw_reset() on shutdown 
soon.

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I've spotted two additional places where the devcom reference is not
cleared after calling mlx5_devcom_unregister_component() in
drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c that I have not
addressed with a patch, since I'm unclear about how to test these
paths.

As for the other cases, we had the patch 664f76be38a1 ("net/mlx5: Fix
IPsec cleanup over MPV device") and two other cases on shared clock and
SD but I don't see any flow the shared clock or SD can fail,
specifically mlx5_sd_cleanup() checks sd pointer at beginning of the
function and nullify it right after sd_unregister() that free devcom.

I didn't locate any calls to mxl5_devcom_unregister_component() in
"shared clock" - is that not yet upstream?

mlx5_shared_clock_unregister() in 
drivers/net/ethernet/mellanox/mlx5/core/lib/clock.c

Regarding SD, I follow that sd_cleanup() is followed immediately after
sd_unregister() and does the clean-up. One path remains uncovered
though: The error exit at
https://elixir.bootlin.com/linux/v6.18/source/drivers/net/ethernet/mellanox/mlx5/core/lib/sd.c#L265

Not sure, how likely that is...

It comes on error flow but after successful 
mlx5_devcom_register_component() in sd_register(), and that error leads 
to error flow in mlx5_sd_init(), which calls sd_cleanup() too.

Thanks,
Gerd