4.14-stable review patch. If anyone has any objections, please let me know.
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From: Corey Minyard cminyard@mvista.com
commit 0745dde62835be7e2afe62fcdb482fcad79cb743 upstream.
The SSIF driver was removing any client that came in through the platform interface, but it should only remove clients that it added. On a failure in the probe function, this could result in the following oops when the driver is removed and the client gets unregistered twice:
CPU: 107 PID: 30266 Comm: rmmod Not tainted 4.18.0+ #80 Hardware name: Cavium Inc. Saber/Saber, BIOS Cavium reference firmware version 7.0 08/04/2018 pstate: 60400009 (nZCv daif +PAN -UAO) pc : kernfs_find_ns+0x28/0x120 lr : kernfs_find_and_get_ns+0x40/0x60 sp : ffff00002310fb50 x29: ffff00002310fb50 x28: ffff800a8240f800 x27: 0000000000000000 x26: 0000000000000000 x25: 0000000056000000 x24: ffff000009073000 x23: ffff000008998b38 x22: 0000000000000000 x21: ffff800ed86de820 x20: 0000000000000000 x19: ffff00000913a1d8 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 5300737265766972 x13: 643d4d4554535953 x12: 0000000000000030 x11: 0000000000000030 x10: 0101010101010101 x9 : ffff800ea06cc3f9 x8 : 0000000000000000 x7 : 0000000000000141 x6 : ffff000009073000 x5 : ffff800adb706b00 x4 : 0000000000000000 x3 : 00000000ffffffff x2 : 0000000000000000 x1 : ffff000008998b38 x0 : ffff000008356760 Process rmmod (pid: 30266, stack limit = 0x00000000e218418d) Call trace: kernfs_find_ns+0x28/0x120 kernfs_find_and_get_ns+0x40/0x60 sysfs_unmerge_group+0x2c/0x6c dpm_sysfs_remove+0x34/0x70 device_del+0x58/0x30c device_unregister+0x30/0x7c i2c_unregister_device+0x84/0x90 [i2c_core] ssif_platform_remove+0x38/0x98 [ipmi_ssif] platform_drv_remove+0x2c/0x6c device_release_driver_internal+0x168/0x1f8 driver_detach+0x50/0xbc bus_remove_driver+0x74/0xe8 driver_unregister+0x34/0x5c platform_driver_unregister+0x20/0x2c cleanup_ipmi_ssif+0x50/0xd82c [ipmi_ssif] __arm64_sys_delete_module+0x1b4/0x220 el0_svc_handler+0x104/0x160 el0_svc+0x8/0xc Code: aa1e03e0 aa0203f6 aa0103f7 d503201f (7940e280) ---[ end trace 09f0e34cce8e2d8c ]--- Kernel panic - not syncing: Fatal exception SMP: stopping secondary CPUs Kernel Offset: disabled CPU features: 0x23800c38
So track the clients that the SSIF driver adds and only remove those.
Reported-by: George Cherian george.cherian@cavium.com Signed-off-by: Corey Minyard cminyard@mvista.com Tested-by: George Cherian george.cherian@cavium.com Cc: stable@vger.kernel.org # 4.14.x Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/char/ipmi/ipmi_ssif.c | 19 +++++++------------ 1 file changed, 7 insertions(+), 12 deletions(-)
--- a/drivers/char/ipmi/ipmi_ssif.c +++ b/drivers/char/ipmi/ipmi_ssif.c @@ -184,6 +184,8 @@ struct ssif_addr_info { struct device *dev; struct i2c_client *client;
+ struct i2c_client *added_client; + struct mutex clients_mutex; struct list_head clients;
@@ -1710,15 +1712,7 @@ static int ssif_probe(struct i2c_client
out: if (rv) { - /* - * Note that if addr_info->client is assigned, we - * leave it. The i2c client hangs around even if we - * return a failure here, and the failure here is not - * propagated back to the i2c code. This seems to be - * design intent, strange as it may be. But if we - * don't leave it, ssif_platform_remove will not remove - * the client like it should. - */ + addr_info->client = NULL; dev_err(&client->dev, "Unable to start IPMI SSIF: %d\n", rv); kfree(ssif_info); } @@ -1737,7 +1731,8 @@ static int ssif_adapter_handler(struct d if (adev->type != &i2c_adapter_type) return 0;
- i2c_new_device(to_i2c_adapter(adev), &addr_info->binfo); + addr_info->added_client = i2c_new_device(to_i2c_adapter(adev), + &addr_info->binfo);
if (!addr_info->adapter_name) return 1; /* Only try the first I2C adapter by default. */ @@ -2018,8 +2013,8 @@ static int ssif_platform_remove(struct p return 0;
mutex_lock(&ssif_infos_mutex); - if (addr_info->client) - i2c_unregister_device(addr_info->client); + if (addr_info->added_client) + i2c_unregister_device(addr_info->added_client);
list_del(&addr_info->link); kfree(addr_info);