[PATCH 5.15 908/917] powerpc/powernv/prd: Unregister OPAL_MSG_PRD2 notifier during module unload

Greg Kroah-Hartman
2021-11-16T00:03:20Z

From: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>

commit 52862ab33c5d97490f3fa345d6529829e6d6637b upstream.

Commit 587164cd, introduced new opal message type (OPAL_MSG_PRD2) and
added opal notifier. But I missed to unregister the notifier during
module unload path. This results in below call trace if you try to
unload and load opal_prd module.

Also add new notifier_block for OPAL_MSG_PRD2 message.

Sample calltrace (modprobe -r opal_prd; modprobe opal_prd)
BUG: Unable to handle kernel data access on read at 0xc0080000192200e0
Faulting instruction address: 0xc00000000018d1cc
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
CPU: 66 PID: 7446 Comm: modprobe Kdump: loaded Tainted: G E 5.14.0prd #759
NIP: c00000000018d1cc LR: c00000000018d2a8 CTR: c0000000000cde10
REGS: c0000003c4c0f0a0 TRAP: 0300 Tainted: G E (5.14.0prd)
MSR: 9000000002009033 <SF,HV,VEC,EE,ME,IR,DR,RI,LE> CR: 24224824 XER: 20040000
CFAR: c00000000018d2a4 DAR: c0080000192200e0 DSISR: 40000000 IRQMASK: 1
...
NIP notifier_chain_register+0x2c/0xc0
LR atomic_notifier_chain_register+0x48/0x80
Call Trace:
0xc000000002090610 (unreliable)
atomic_notifier_chain_register+0x58/0x80
opal_message_notifier_register+0x7c/0x1e0
opal_prd_probe+0x84/0x150 [opal_prd]
platform_probe+0x78/0x130
really_probe+0x110/0x5d0
__driver_probe_device+0x17c/0x230
driver_probe_device+0x60/0x130
__driver_attach+0xfc/0x220
bus_for_each_dev+0xa8/0x130
driver_attach+0x34/0x50
bus_add_driver+0x1b0/0x300
driver_register+0x98/0x1a0
__platform_driver_register+0x38/0x50
opal_prd_driver_init+0x34/0x50 [opal_prd]
do_one_initcall+0x60/0x2d0
do_init_module+0x7c/0x320
load_module+0x3394/0x3650
__do_sys_finit_module+0xd4/0x160
system_call_exception+0x140/0x290
system_call_common+0xf4/0x258

Fixes: 587164cd593c ("powerpc/powernv: Add new opal message type")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211028165716.41300-1-hegdevasant@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/platforms/powernv/opal-prd.c | 12 +++++++++++-
1 file changed, 11 insertions(+), 1 deletion(-)

--- a/arch/powerpc/platforms/powernv/opal-prd.c
+++ b/arch/powerpc/platforms/powernv/opal-prd.c
@@ -369,6 +369,12 @@ static struct notifier_block opal_prd_ev
.priority = 0,
};

+static struct notifier_block opal_prd_event_nb2 = {
+ .notifier_call = opal_prd_msg_notifier,
+ .next = NULL,
+ .priority = 0,
+};
+
static int opal_prd_probe(struct platform_device *pdev)
{
int rc;
@@ -390,9 +396,10 @@ static int opal_prd_probe(struct platfor
return rc;
}

- rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb);
+ rc = opal_message_notifier_register(OPAL_MSG_PRD2, &opal_prd_event_nb2);
if (rc) {
pr_err("Couldn't register PRD2 event notifier\n");
+ opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
return rc;
}

@@ -401,6 +408,8 @@ static int opal_prd_probe(struct platfor
pr_err("failed to register miscdev\n");
opal_message_notifier_unregister(OPAL_MSG_PRD,
&opal_prd_event_nb);
+ opal_message_notifier_unregister(OPAL_MSG_PRD2,
+ &opal_prd_event_nb2);
return rc;
}

@@ -411,6 +420,7 @@ static int opal_prd_remove(struct platfo
{
misc_deregister(&opal_prd_dev);
opal_message_notifier_unregister(OPAL_MSG_PRD, &opal_prd_event_nb);
+ opal_message_notifier_unregister(OPAL_MSG_PRD2, &opal_prd_event_nb2);
return 0;
}