net: mana: Fix use-after-free in reset service rescan path

When mana_serv_reset() encounters -ETIMEDOUT or -EPROTO from
mana_gd_resume(), it performs a PCI rescan via mana_serv_rescan().

mana_serv_rescan() calls pci_stop_and_remove_bus_device(), which can
invoke the driver's remove path and free the gdma_context associated
with the device. After returning, mana_serv_reset() currently jumps to
the out label and attempts to clear gc->in_service, dereferencing a
freed gdma_context.

The issue was observed with the following call logs:
[  698.942636] BUG: unable to handle page fault for address: ff6c2b638088508d
[  698.943121] #PF: supervisor write access in kernel mode
[  698.943423] #PF: error_code(0x0002) - not-present page
[S[  698.943793] Pat Dec  6 07:GD5 100000067 P4D 1002f7067 PUD 1002f8067 PMD 101bef067 PTE 0
0:56 2025] hv_[n e 698.944283] Oops: Oops: 0002 [#1] SMP NOPTI
tvsc f8615163-00[  698.944611] CPU: 28 UID: 0 PID: 249 Comm: kworker/28:1
...
[Sat Dec  6 07:50:56 2025] R10: [  699.121594] mana 7870:00:00.0 enP30832s1: Configured vPort 0 PD 18 DB 16
000000000000001b R11: 0000000000000000 R12: ff44cf3f40270000
[Sat Dec  6 07:50:56 2025] R13: 0000000000000001 R14: ff44cf3f402700c8 R15: ff44cf3f4021b405
[Sat Dec  6 07:50:56 2025] FS:  0000000000000000(0000) GS:ff44cf7e9fcf9000(0000) knlGS:0000000000000000
[Sat Dec  6 07:50:56 2025] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[Sat Dec  6 07:50:56 2025] CR2: ff6c2b638088508d CR3: 000000011fe43001 CR4: 0000000000b73ef0
[Sat Dec  6 07:50:56 2025] Call Trace:
[Sat Dec  6 07:50:56 2025]  <TASK>
[Sat Dec  6 07:50:56 2025]  mana_serv_func+0x24/0x50 [mana]
[Sat Dec  6 07:50:56 2025]  process_one_work+0x190/0x350
[Sat Dec  6 07:50:56 2025]  worker_thread+0x2b7/0x3d0
[Sat Dec  6 07:50:56 2025]  kthread+0xf3/0x200
[Sat Dec  6 07:50:56 2025]  ? __pfx_worker_thread+0x10/0x10
[Sat Dec  6 07:50:56 2025]  ? __pfx_kthread+0x10/0x10
[Sat Dec  6 07:50:56 2025]  ret_from_fork+0x21a/0x250
[Sat Dec  6 07:50:56 2025]  ? __pfx_kthread+0x10/0x10
[Sat Dec  6 07:50:56 2025]  ret_from_fork_asm+0x1a/0x30
[Sat Dec  6 07:50:56 2025]  </TASK>

Fix this by returning immediately after mana_serv_rescan() to avoid
accessing GC state that may no longer be valid.

Fixes: 9bf6603 ("net: mana: Handle hardware recovery events when probing the device")
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Long Li <longli@microsoft.com>
Signed-off-by: Dipayaan Roy <dipayanroy@linux.microsoft.com>
Signed-off-by: NipaLocal <nipa@local>

Author: Dipayaan Roy

drivers/net/ethernet/microsoft/mana/gdma_main.c

@@ -481,7 +481,7 @@ static void mana_serv_reset(struct pci_dev *pdev)
 		/* Perform PCI rescan on device if we failed on HWC */
 		dev_err(&pdev->dev, "MANA service: resume failed, rescanning\n");
 		mana_serv_rescan(pdev);
-		goto out;
+		return;
 	}
 
 	if (ret)