net: mana: cleanup mana struct after debugfs_remove()

Maxim Levitsky · Maxim Levitsky · commit a0c6be5a6322 · 2025-06-16T14:00:52.000-04:00
JIRA: https://issues.redhat.com/browse/RHEL-80096 commit 3e64bb2 Author: Shradha Gupta <shradhagupta@linux.microsoft.com> Date: Tue Mar 11 03:17:40 2025 -0700 net: mana: cleanup mana struct after debugfs_remove() When on a MANA VM hibernation is triggered, as part of hibernate_snapshot(), mana_gd_suspend() and mana_gd_resume() are called. If during this mana_gd_resume(), a failure occurs with HWC creation, mana_port_debugfs pointer does not get reinitialized and ends up pointing to older, cleaned-up dentry. Further in the hibernation path, as part of power_down(), mana_gd_shutdown() is triggered. This call, unaware of the failures in resume, tries to cleanup the already cleaned up mana_port_debugfs value and hits the following bug: [ 191.359296] mana 7870:00:00.0: Shutdown was called [ 191.359918] BUG: kernel NULL pointer dereference, address: 0000000000000098 [ 191.360584] #PF: supervisor write access in kernel mode [ 191.361125] #PF: error_code(0x0002) - not-present page [ 191.361727] PGD 1080ea067 P4D 0 [ 191.362172] Oops: Oops: 0002 [#1] SMP NOPTI [ 191.362606] CPU: 11 UID: 0 PID: 1674 Comm: bash Not tainted 6.14.0-rc5+ #2 [ 191.363292] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 11/21/2024 [ 191.364124] RIP: 0010:down_write+0x19/0x50 [ 191.364537] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb e8 de cd ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 13 75 16 65 48 8b 05 88 24 4c 6a 48 89 43 08 48 8b 5d [ 191.365867] RSP: 0000:ff45fbe0c1c037b8 EFLAGS: 00010246 [ 191.366350] RAX: 0000000000000000 RBX: 0000000000000098 RCX: ffffff8100000000 [ 191.366951] RDX: 0000000000000001 RSI: 0000000000000064 RDI: 0000000000000098 [ 191.367600] RBP: ff45fbe0c1c037c0 R08: 0000000000000000 R09: 0000000000000001 [ 191.368225] R10: ff45fbe0d2b01000 R11: 0000000000000008 R12: 0000000000000000 [ 191.368874] R13: 000000000000000b R14: ff43dc27509d67c0 R15: 0000000000000020 [ 191.369549] FS: 00007dbc5001e740(0000) GS:ff43dc663f380000(0000) knlGS:0000000000000000 [ 191.370213] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 191.370830] CR2: 0000000000000098 CR3: 0000000168e8e002 CR4: 0000000000b73ef0 [ 191.371557] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 191.372192] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 [ 191.372906] Call Trace: [ 191.373262] <TASK> [ 191.373621] ? show_regs+0x64/0x70 [ 191.374040] ? __die+0x24/0x70 [ 191.374468] ? page_fault_oops+0x290/0x5b0 [ 191.374875] ? do_user_addr_fault+0x448/0x800 [ 191.375357] ? exc_page_fault+0x7a/0x160 [ 191.375971] ? asm_exc_page_fault+0x27/0x30 [ 191.376416] ? down_write+0x19/0x50 [ 191.376832] ? down_write+0x12/0x50 [ 191.377232] simple_recursive_removal+0x4a/0x2a0 [ 191.377679] ? __pfx_remove_one+0x10/0x10 [ 191.378088] debugfs_remove+0x44/0x70 [ 191.378530] mana_detach+0x17c/0x4f0 [ 191.378950] ? __flush_work+0x1e2/0x3b0 [ 191.379362] ? __cond_resched+0x1a/0x50 [ 191.379787] mana_remove+0xf2/0x1a0 [ 191.380193] mana_gd_shutdown+0x3b/0x70 [ 191.380642] pci_device_shutdown+0x3a/0x80 [ 191.381063] device_shutdown+0x13e/0x230 [ 191.381480] kernel_power_off+0x35/0x80 [ 191.381890] hibernate+0x3c6/0x470 [ 191.382312] state_store+0xcb/0xd0 [ 191.382734] kobj_attr_store+0x12/0x30 [ 191.383211] sysfs_kf_write+0x3e/0x50 [ 191.383640] kernfs_fop_write_iter+0x140/0x1d0 [ 191.384106] vfs_write+0x271/0x440 [ 191.384521] ksys_write+0x72/0xf0 [ 191.384924] __x64_sys_write+0x19/0x20 [ 191.385313] x64_sys_call+0x2b0/0x20b0 [ 191.385736] do_syscall_64+0x79/0x150 [ 191.386146] ? __mod_memcg_lruvec_state+0xe7/0x240 [ 191.386676] ? __lruvec_stat_mod_folio+0x79/0xb0 [ 191.387124] ? __pfx_lru_add+0x10/0x10 [ 191.387515] ? queued_spin_unlock+0x9/0x10 [ 191.387937] ? do_anonymous_page+0x33c/0xa00 [ 191.388374] ? __handle_mm_fault+0xcf3/0x1210 [ 191.388805] ? __count_memcg_events+0xbe/0x180 [ 191.389235] ? handle_mm_fault+0xae/0x300 [ 191.389588] ? do_user_addr_fault+0x559/0x800 [ 191.390027] ? irqentry_exit_to_user_mode+0x43/0x230 [ 191.390525] ? irqentry_exit+0x1d/0x30 [ 191.390879] ? exc_page_fault+0x86/0x160 [ 191.391235] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 191.391745] RIP: 0033:0x7dbc4ff1c574 [ 191.392111] Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89 [ 191.393412] RSP: 002b:00007ffd95a23ab8 EFLAGS: 00000202 ORIG_RAX: 0000000000000001 [ 191.393990] RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007dbc4ff1c574 [ 191.394594] RDX: 0000000000000005 RSI: 00005a6eeadb0ce0 RDI: 0000000000000001 [ 191.395215] RBP: 00007ffd95a23ae0 R08: 00007dbc50003b20 R09: 0000000000000000 [ 191.395805] R10: 0000000000000001 R11: 0000000000000202 R12: 0000000000000005 [ 191.396404] R13: 00005a6eeadb0ce0 R14: 00007dbc500045c0 R15: 00007dbc50001ee0 [ 191.396987] </TASK> To fix this, we explicitly set such mana debugfs variables to NULL after debugfs_remove() is called. Fixes: 6607c17 ("net: mana: Enable debugfs files for MANA device") Cc: stable@vger.kernel.org Signed-off-by: Shradha Gupta <shradhagupta@linux.microsoft.com> Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: Michal Kubiak <michal.kubiak@intel.com> Link: https://patch.msgid.link/1741688260-28922-1-git-send-email-shradhagupta@linux.microsoft.com Signed-off-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -1548,6 +1548,7 @@ static int mana_gd_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	 * adapter-MTU file and apc->mana_pci_debugfs folder.
 	 */
 	debugfs_remove_recursive(gc->mana_pci_debugfs);
+	gc->mana_pci_debugfs = NULL;
 	pci_iounmap(pdev, bar0_va);
 free_gc:
 	pci_set_drvdata(pdev, NULL);
@@ -1570,6 +1571,8 @@ static void mana_gd_remove(struct pci_dev *pdev)
 
 	debugfs_remove_recursive(gc->mana_pci_debugfs);
 
+	gc->mana_pci_debugfs = NULL;
+
 	pci_iounmap(pdev, gc->bar0_va);
 
 	vfree(gc);
@@ -1623,6 +1626,8 @@ static void mana_gd_shutdown(struct pci_dev *pdev)
 
 	debugfs_remove_recursive(gc->mana_pci_debugfs);
 
+	gc->mana_pci_debugfs = NULL;
+
 	pci_disable_device(pdev);
 }
 
@@ -1649,8 +1654,10 @@ static int __init mana_driver_init(void)
 	mana_debugfs_root = debugfs_create_dir("mana", NULL);
 
 	err = pci_register_driver(&mana_driver);
-	if (err)
+	if (err) {
 		debugfs_remove(mana_debugfs_root);
+		mana_debugfs_root = NULL;
+	}
 
 	return err;
 }
@@ -1660,6 +1667,8 @@ static void __exit mana_driver_exit(void)
 	pci_unregister_driver(&mana_driver);
 
 	debugfs_remove(mana_debugfs_root);
+
+	mana_debugfs_root = NULL;
 }
 
 module_init(mana_driver_init);
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -737,12 +737,11 @@ static const struct net_device_ops mana_devops = {
 static void mana_cleanup_port_context(struct mana_port_context *apc)
 {
 	/*
-	 * at this point all dir/files under the vport directory
-	 * are already cleaned up.
-	 * We are sure the apc->mana_port_debugfs remove will not
-	 * cause any freed memory access issues
+	 * make sure subsequent cleanup attempts don't end up removing already
+	 * cleaned dentry pointer
 	 */
 	debugfs_remove(apc->mana_port_debugfs);
+	apc->mana_port_debugfs = NULL;
 	kfree(apc->rxqs);
 	apc->rxqs = NULL;
 }
@@ -1253,6 +1252,7 @@ static void mana_destroy_eq(struct mana_context *ac)
 		return;
 
 	debugfs_remove_recursive(ac->mana_eqs_debugfs);
+	ac->mana_eqs_debugfs = NULL;
 
 	for (i = 0; i < gc->max_num_queues; i++) {
 		eq = ac->eqs[i].eq;
@@ -1913,6 +1913,7 @@ static void mana_destroy_txq(struct mana_port_context *apc)
 
 	for (i = 0; i < apc->num_queues; i++) {
 		debugfs_remove_recursive(apc->tx_qp[i].mana_tx_debugfs);
+		apc->tx_qp[i].mana_tx_debugfs = NULL;
 
 		napi = &apc->tx_qp[i].tx_cq.napi;
 		if (apc->tx_qp[i].txq.napi_initialized) {
@@ -2098,6 +2099,7 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
 		return;
 
 	debugfs_remove_recursive(rxq->mana_rx_debugfs);
+	rxq->mana_rx_debugfs = NULL;
 
 	napi = &rxq->rx_cq.napi;
 
