Patch "svcrdma: fix miss destroy percpu_counter in svc_rdma_proc_init()" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    svcrdma: fix miss destroy percpu_counter in svc_rdma_proc_init()

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     svcrdma-fix-miss-destroy-percpu_counter-in-svc_rdma_.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 5f2fe1180b3b3376e7837a44739c93879569ec25
Author: Ye Bin <yebin10@xxxxxxxxxx>
Date:   Thu Oct 24 09:55:20 2024 +0800

    svcrdma: fix miss destroy percpu_counter in svc_rdma_proc_init()
    
    [ Upstream commit ce89e742a4c12b20f09a43fec1b21db33f2166cd ]
    
    There's issue as follows:
    RPC: Registered rdma transport module.
    RPC: Registered rdma backchannel transport module.
    RPC: Unregistered rdma transport module.
    RPC: Unregistered rdma backchannel transport module.
    BUG: unable to handle page fault for address: fffffbfff80c609a
    PGD 123fee067 P4D 123fee067 PUD 123fea067 PMD 10c624067 PTE 0
    Oops: Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI
    RIP: 0010:percpu_counter_destroy_many+0xf7/0x2a0
    Call Trace:
     <TASK>
     __die+0x1f/0x70
     page_fault_oops+0x2cd/0x860
     spurious_kernel_fault+0x36/0x450
     do_kern_addr_fault+0xca/0x100
     exc_page_fault+0x128/0x150
     asm_exc_page_fault+0x26/0x30
     percpu_counter_destroy_many+0xf7/0x2a0
     mmdrop+0x209/0x350
     finish_task_switch.isra.0+0x481/0x840
     schedule_tail+0xe/0xd0
     ret_from_fork+0x23/0x80
     ret_from_fork_asm+0x1a/0x30
     </TASK>
    
    If register_sysctl() return NULL, then svc_rdma_proc_cleanup() will not
    destroy the percpu counters which init in svc_rdma_proc_init().
    If CONFIG_HOTPLUG_CPU is enabled, residual nodes may be in the
    'percpu_counters' list. The above issue may occur once the module is
    removed. If the CONFIG_HOTPLUG_CPU configuration is not enabled, memory
    leakage occurs.
    To solve above issue just destroy all percpu counters when
    register_sysctl() return NULL.
    
    Fixes: 1e7e55731628 ("svcrdma: Restore read and write stats")
    Fixes: 22df5a22462e ("svcrdma: Convert rdma_stat_sq_starve to a per-CPU counter")
    Fixes: df971cd853c0 ("svcrdma: Convert rdma_stat_recv to a per-CPU counter")
    Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx>
    Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/net/sunrpc/xprtrdma/svc_rdma.c b/net/sunrpc/xprtrdma/svc_rdma.c
index f0d5eeed4c886..e1d4e426b21fa 100644
--- a/net/sunrpc/xprtrdma/svc_rdma.c
+++ b/net/sunrpc/xprtrdma/svc_rdma.c
@@ -234,25 +234,34 @@ static int svc_rdma_proc_init(void)
 
 	rc = percpu_counter_init(&svcrdma_stat_read, 0, GFP_KERNEL);
 	if (rc)
-		goto out_err;
+		goto err;
 	rc = percpu_counter_init(&svcrdma_stat_recv, 0, GFP_KERNEL);
 	if (rc)
-		goto out_err;
+		goto err_read;
 	rc = percpu_counter_init(&svcrdma_stat_sq_starve, 0, GFP_KERNEL);
 	if (rc)
-		goto out_err;
+		goto err_recv;
 	rc = percpu_counter_init(&svcrdma_stat_write, 0, GFP_KERNEL);
 	if (rc)
-		goto out_err;
+		goto err_sq;
 
 	svcrdma_table_header = register_sysctl("sunrpc/svc_rdma",
 					       svcrdma_parm_table);
+	if (!svcrdma_table_header)
+		goto err_write;
+
 	return 0;
 
-out_err:
+err_write:
+	rc = -ENOMEM;
+	percpu_counter_destroy(&svcrdma_stat_write);
+err_sq:
 	percpu_counter_destroy(&svcrdma_stat_sq_starve);
+err_recv:
 	percpu_counter_destroy(&svcrdma_stat_recv);
+err_read:
 	percpu_counter_destroy(&svcrdma_stat_read);
+err:
 	return rc;
 }