Re: [PATCH net] net: mana: Fix double destroy_workqueue on service rescan PCI path
From: Simon Horman
Date: Wed Feb 25 2026 - 08:22:52 EST
+ Leon
On Tue, Feb 24, 2026 at 04:38:36AM -0800, Dipayaan Roy wrote:
> While testing corner cases in the driver, a use-after-free crash
> was found on the service rescan PCI path.
>
> When mana_serv_reset() calls mana_gd_suspend(), mana_gd_cleanup()
> destroys gc->service_wq. If the subsequent mana_gd_resume() fails
> with -ETIMEDOUT or -EPROTO, the code falls through to
> mana_serv_rescan() which triggers pci_stop_and_remove_bus_device().
> This invokes the PCI .remove callback (mana_gd_remove), which calls
> mana_gd_cleanup() a second time, attempting to destroy the already-
> freed workqueue. Fix this by NULL-checking gc->service_wq in
> mana_gd_cleanup() and setting it to NULL after destruction.
>
> Call stack of issue for reference:
> [Sat Feb 21 18:53:48 2026] Call Trace:
> [Sat Feb 21 18:53:48 2026] <TASK>
> [Sat Feb 21 18:53:48 2026] mana_gd_cleanup+0x33/0x70 [mana]
> [Sat Feb 21 18:53:48 2026] mana_gd_remove+0x3a/0xc0 [mana]
> [Sat Feb 21 18:53:48 2026] pci_device_remove+0x41/0xb0
> [Sat Feb 21 18:53:48 2026] device_remove+0x46/0x70
> [Sat Feb 21 18:53:48 2026] device_release_driver_internal+0x1e3/0x250
> [Sat Feb 21 18:53:48 2026] device_release_driver+0x12/0x20
> [Sat Feb 21 18:53:48 2026] pci_stop_bus_device+0x6a/0x90
> [Sat Feb 21 18:53:48 2026] pci_stop_and_remove_bus_device+0x13/0x30
> [Sat Feb 21 18:53:48 2026] mana_do_service+0x180/0x290 [mana]
> [Sat Feb 21 18:53:48 2026] mana_serv_func+0x24/0x50 [mana]
> [Sat Feb 21 18:53:48 2026] process_one_work+0x190/0x3d0
> [Sat Feb 21 18:53:48 2026] worker_thread+0x16e/0x2e0
> [Sat Feb 21 18:53:48 2026] kthread+0xf7/0x130
> [Sat Feb 21 18:53:48 2026] ? __pfx_worker_thread+0x10/0x10
> [Sat Feb 21 18:53:48 2026] ? __pfx_kthread+0x10/0x10
> [Sat Feb 21 18:53:48 2026] ret_from_fork+0x269/0x350
> [Sat Feb 21 18:53:48 2026] ? __pfx_kthread+0x10/0x10
> [Sat Feb 21 18:53:48 2026] ret_from_fork_asm+0x1a/0x30
> [Sat Feb 21 18:53:48 2026] </TASK>
>
> Fixes: 505cc26bcae0 ("net: mana: Add support for auxiliary device servicing events")
> Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> Signed-off-by: Dipayaan Roy <dipayanroy@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Simon Horman <horms@xxxxxxxxxx>
> ---
> drivers/net/ethernet/microsoft/mana/gdma_main.c | 5 ++++-
> drivers/net/ethernet/microsoft/mana/mana_en.c | 4 +++-
> 2 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> index 0055c231acf6..3926d18f1840 100644
> --- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
> +++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
> @@ -1946,7 +1946,10 @@ static void mana_gd_cleanup(struct pci_dev *pdev)
>
> mana_gd_remove_irqs(pdev);
>
> - destroy_workqueue(gc->service_wq);
> + if (gc->service_wq) {
> + destroy_workqueue(gc->service_wq);
> + gc->service_wq = NULL;
> + }
> dev_dbg(&pdev->dev, "mana gdma cleanup successful\n");
> }
>
> diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
> index 9b5a72ada5c4..f69e42651359 100644
> --- a/drivers/net/ethernet/microsoft/mana/mana_en.c
> +++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
> @@ -3762,7 +3762,9 @@ void mana_rdma_remove(struct gdma_dev *gd)
> }
>
> WRITE_ONCE(gd->rdma_teardown, true);
> - flush_workqueue(gc->service_wq);
> +
> + if (gc->service_wq)
> + flush_workqueue(gc->service_wq);
>
> if (gd->adev)
> remove_adev(gd);
> --
> 2.43.0
>