Messages in this thread | | | Subject | Re: [PATCH] ipmi: Fix I2C client removal in the SSIF driver | From | George Cherian <> | Date | Fri, 31 Aug 2018 17:28:40 +0530 |
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On 08/30/2018 11:44 PM, minyard@acm.org wrote: > > From: Corey Minyard <cminyard@mvista.com> > > 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> > --- > drivers/char/ipmi/ipmi_ssif.c | 17 ++++++----------- > 1 file changed, 6 insertions(+), 11 deletions(-) > > George, your fix was close, but not quite right. The following > should fix the problem, obvious in hindsight :-). Thanks for working > with me on this. > Thanks Corey!!! This works for me now.
> -corey > > diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c > index e7e8b86..ca4f7c4 100644 > --- a/drivers/char/ipmi/ipmi_ssif.c > +++ b/drivers/char/ipmi/ipmi_ssif.c > @@ -182,6 +182,8 @@ struct ssif_addr_info { > struct device *dev; > struct i2c_client *client; > > + struct i2c_client *added_client; > + > struct mutex clients_mutex; > struct list_head clients; > > @@ -1639,15 +1641,7 @@ static int ssif_probe(struct i2c_client *client, const struct i2c_device_id *id) > > 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); > } > @@ -1667,7 +1661,8 @@ static int ssif_adapter_handler(struct device *adev, void *opaque) > 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. */ > @@ -1840,7 +1835,7 @@ static int ssif_platform_remove(struct platform_device *dev) > return 0; > > mutex_lock(&ssif_infos_mutex); > - i2c_unregister_device(addr_info->client); > + i2c_unregister_device(addr_info->added_client); > > list_del(&addr_info->link); > kfree(addr_info); > -- > 2.7.4 >
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