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From:   Olof Johansson <olof@lixom.net>
To:     Corey Minyard <minyard@acm.org>
Cc:     openipmi-developer@lists.sourceforge.net,
        linux-kernel@vger.kernel.org, Olof Johansson <olof@lixom.net>
Subject: [PATCH] ipmi: initialize platform driver even when using passed-in config
Date:   Fri,  6 Jul 2018 11:43:01 -0700
Message-Id: <20180706184301.12890-1-olof@lixom.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On platforms where manual values are passed in when the module is loaded
(or through kernel command line), the device is instantiated with a
reference to the platform driver, but the platform driver never gets
initialized and loaded.

Instead, always initialize the driver, but override any SMBIOS-found
entries with the hardcoded values where they are in conflict.

Crash is as below:

[   20.052087] BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
[   20.067730] PGD 0
[   20.071821] P4D 0
[   20.075836] Oops: 0000 [#1] SMP PTI
[   20.082864] CPU: 1 PID: 1330 Comm: systemd-udevd Not tainted 4.18.0-rc3-00134-g06c85639897c #10
[   20.100394] Hardware name: <...>
[   20.121583] RIP: 0010:sysfs_do_create_link_sd.isra.2+0x2f/0xa0
[   20.361345] RSP: 0018:ffffc9000fab7b10 EFLAGS: 00010246
[   20.371765] RAX: 0000000000000000 RBX: 0000000000000030 RCX: 0000000000000001
[   20.386072] RDX: 0000000000000001 RSI: 0000000000000030 RDI: ffffffff82a8ef2c
[   20.400312] RBP: ffffffff820dcdda R08: 0000000000000001 R09: 0000000000000044
[   20.414560] R10: 0000000000000220 R11: ffff883ff80471e9 R12: ffff881fee1646e8
[   20.428808] R13: 0000000000000001 R14: 0000000000000001 R15: 0000000000000000
[   20.443056] FS:  00007f9d6c1e7940(0000) GS:ffff881ffff80000(0000) knlGS:0000000000000000
[   20.459210] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   20.470685] CR2: 0000000000000030 CR3: 0000003fd1872006 CR4: 00000000007606e0
[   20.484934] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[   20.499182] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[   20.513430] PKRU: 55555554
[   20.518837] Call Trace:
[   20.523729]  driver_sysfs_add+0x75/0xa0
[   20.531388]  device_bind_driver+0xf/0x50
[   20.539223]  __device_attach+0x89/0x100
[   20.546885]  ? kobject_uevent_env+0x109/0x530
[   20.555585]  bus_probe_device+0x8a/0xa0
[   20.563245]  device_add+0x3df/0x590
[   20.570214]  platform_device_add+0xb9/0x220
[   20.578571]  try_smi_init+0x785/0x930 [ipmi_si]
[   20.587618]  init_ipmi_si+0xfd/0x1a0 [ipmi_si]
[   20.596493]  ? cleanup_ipmi_si+0x80/0x80 [ipmi_si]
[   20.606060]  do_one_initcall+0x4e/0x1c9
[   20.613722]  ? kmem_cache_alloc_trace+0x14e/0x1a0
[   20.623118]  ? do_init_module+0x22/0x213
[   20.630950]  do_init_module+0x5a/0x213
[   20.638438]  load_module+0x1cef/0x2650
[   20.645927]  ? m_show+0x1c0/0x1c0
[   20.652550]  ? security_capable+0x3f/0x60
[   20.660555]  __do_sys_finit_module+0xb2/0xc0
[   20.669083]  do_syscall_64+0x49/0xf0
[   20.676225]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Signed-off-by: Olof Johansson <olof@lixom.net>
---
 drivers/char/ipmi/ipmi_si_intf.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_si_intf.c b/drivers/char/ipmi/ipmi_si_intf.c
index dd758223c56d..6ddfc8be0c76 100644
--- a/drivers/char/ipmi/ipmi_si_intf.c
+++ b/drivers/char/ipmi/ipmi_si_intf.c
@@ -2018,7 +2018,13 @@ int ipmi_si_add_smi(struct si_sm_io *io)
 	mutex_lock(&smi_infos_lock);
 	dup = find_dup_si(new_smi);
 	if (dup) {
-		if (new_smi->io.addr_source == SI_ACPI &&
+		if (new_smi->io.addr_source == SI_HARDCODED) {
+			/* Assume the user knew what they wanted when they hardcoded */
+			dev_info(dup->io.dev,
+				"Removing discovered %s state machine in favor of hardcoded\n",
+				si_to_str[new_smi->io.si_type]);
+			cleanup_one_si(dup);
+		} else if (new_smi->io.addr_source == SI_ACPI &&
 		    dup->io.addr_source == SI_SMBIOS) {
 			/* We prefer ACPI over SMBIOS. */
 			dev_info(dup->io.dev,
@@ -2341,12 +2347,13 @@ static int init_ipmi_si(void)
 
 	pr_info("IPMI System Interface driver.\n");
 
+	/* Always platform since hardcoded entries rely on it. */
+	ipmi_si_platform_init();
+
 	/* If the user gave us a device, they presumably want us to use it */
 	if (!ipmi_si_hardcode_find_bmc())
 		goto do_scan;
 
-	ipmi_si_platform_init();
-
 	ipmi_si_pci_init();
 
 	ipmi_si_parisc_init();
-- 
2.17.1