Messages in this thread | | | Subject | Re: [PATCH v4] driver core: auxiliary bus: Fix calling stage for auxiliary bus init | From | Dave Jiang <> | Date | Thu, 11 Feb 2021 11:14:09 -0700 |
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On 2/11/2021 10:59 AM, Greg KH wrote: > On Thu, Feb 11, 2021 at 10:42:49AM -0700, Dave Jiang wrote: >> When the auxiliary device code is built into the kernel, it can be executed >> before the auxiliary bus is registered. This causes bus->p to be not >> allocated and triggers a NULL pointer dereference when the auxiliary bus >> device gets added with bus_add_device(). Call the auxiliary_bus_init() >> under driver_init() so the bus is initialized before devices. >> >> Below is the kernel splat for the bug: >> [ 1.948215] BUG: kernel NULL pointer dereference, address: 0000000000000060 >> [ 1.950670] #PF: supervisor read access in kernel mode >> [ 1.950670] #PF: error_code(0x0000) - not-present page >> [ 1.950670] PGD 0 >> [ 1.950670] Oops: 0000 1 SMP NOPTI >> [ 1.950670] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.10.0-intel-nextsvmtest+ #2205 >> [ 1.950670] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 >> [ 1.950670] RIP: 0010:bus_add_device+0x64/0x140 >> [ 1.950670] Code: 00 49 8b 75 20 48 89 df e8 59 a1 ff ff 41 89 c4 85 c0 75 7b 48 8b 53 50 48 85 d2 75 03 48 8b 13 49 8b 85 a0 00 00 00 48 89 de <48> 8 >> 78 60 48 83 c7 18 e8 ef d9 a9 ff 41 89 c4 85 c0 75 45 48 8b >> [ 1.950670] RSP: 0000:ff46032ac001baf8 EFLAGS: 00010246 >> [ 1.950670] RAX: 0000000000000000 RBX: ff4597f7414aa680 RCX: 0000000000000000 >> [ 1.950670] RDX: ff4597f74142bbc0 RSI: ff4597f7414aa680 RDI: ff4597f7414aa680 >> [ 1.950670] RBP: ff46032ac001bb10 R08: 0000000000000044 R09: 0000000000000228 >> [ 1.950670] R10: ff4597f741141b30 R11: ff4597f740182a90 R12: 0000000000000000 >> [ 1.950670] R13: ffffffffa5e936c0 R14: 0000000000000000 R15: 0000000000000000 >> [ 1.950670] FS: 0000000000000000(0000) GS:ff4597f7bba00000(0000) knlGS:0000000000000000 >> [ 1.950670] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 1.950670] CR2: 0000000000000060 CR3: 000000002140c001 CR4: 0000000000f71ef0 >> [ 1.950670] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> [ 1.950670] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400 >> [ 1.950670] PKRU: 55555554 >> [ 1.950670] Call Trace: >> [ 1.950670] device_add+0x3ee/0x850 >> [ 1.950670] __auxiliary_device_add+0x47/0x60 >> [ 1.950670] idxd_pci_probe+0xf77/0x1180 >> [ 1.950670] local_pci_probe+0x4a/0x90 >> [ 1.950670] pci_device_probe+0xff/0x1b0 >> [ 1.950670] really_probe+0x1cf/0x440 >> [ 1.950670] ? rdinit_setup+0x31/0x31 >> [ 1.950670] driver_probe_device+0xe8/0x150 >> [ 1.950670] device_driver_attach+0x58/0x60 >> [ 1.950670] __driver_attach+0x8f/0x150 >> [ 1.950670] ? device_driver_attach+0x60/0x60 >> [ 1.950670] ? device_driver_attach+0x60/0x60 >> [ 1.950670] bus_for_each_dev+0x79/0xc0 >> [ 1.950670] ? kmem_cache_alloc_trace+0x323/0x430 >> [ 1.950670] driver_attach+0x1e/0x20 >> [ 1.950670] bus_add_driver+0x154/0x1f0 >> [ 1.950670] driver_register+0x70/0xc0 >> [ 1.950670] __pci_register_driver+0x54/0x60 >> [ 1.950670] idxd_init_module+0xe2/0xfc >> [ 1.950670] ? idma64_platform_driver_init+0x19/0x19 >> [ 1.950670] do_one_initcall+0x4a/0x1e0 >> [ 1.950670] kernel_init_freeable+0x1fc/0x25c >> [ 1.950670] ? rest_init+0xba/0xba >> [ 1.950670] kernel_init+0xe/0x116 >> [ 1.950670] ret_from_fork+0x1f/0x30 >> [ 1.950670] Modules linked in: >> [ 1.950670] CR2: 0000000000000060 >> [ 1.950670] --[ end trace cd7d1b226d3ca901 ]-- >> >> Fixes: 7de3697e9cbd ("Add auxiliary bus support") >> Reported-by: Jacob Pan <jacob.jun.pan@intel.com> >> Acked-by: Dave Ertman <david.m.ertman@intel.com> >> Reviewed-by: Dan Williams <dan.j.williams@intel.com> >> Signed-off-by: Dave Jiang <dave.jiang@intel.com> >> --- >> >> v4: >> - Remove remaining module bits as it's not a kernel module. (GregKH) >> v3: >> - Change init function to return void. (GregKH) >> v2: >> - Call in driver_init() to ensure aux bus gets init before devices. (GregKH) >> >> drivers/base/base.h | 5 +++++ >> drivers/base/auxiliary.c | 18 +++--------------- >> drivers/base/init.c | 1 + >> 3 files changed, 9 insertions(+), 15 deletions(-) >> >> diff --git a/drivers/base/base.h b/drivers/base/base.h >> index f5600a83124f..52b3d7b75c27 100644 >> --- a/drivers/base/base.h >> +++ b/drivers/base/base.h >> @@ -119,6 +119,11 @@ static inline int hypervisor_init(void) { return 0; } >> extern int platform_bus_init(void); >> extern void cpu_dev_init(void); >> extern void container_dev_init(void); >> +#ifdef CONFIG_AUXILIARY_BUS >> +extern void auxiliary_bus_init(void); >> +#else >> +static inline void auxiliary_bus_init(void) { } >> +#endif >> >> struct kobject *virtual_device_parent(struct device *dev); >> >> diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c >> index 8336535f1e11..adc199dfba3c 100644 >> --- a/drivers/base/auxiliary.c >> +++ b/drivers/base/auxiliary.c >> @@ -15,6 +15,7 @@ >> #include <linux/pm_runtime.h> >> #include <linux/string.h> >> #include <linux/auxiliary_bus.h> >> +#include "base.h" >> >> static const struct auxiliary_device_id *auxiliary_match_id(const struct auxiliary_device_id *id, >> const struct auxiliary_device *auxdev) >> @@ -260,20 +261,7 @@ void auxiliary_driver_unregister(struct auxiliary_driver *auxdrv) >> } >> EXPORT_SYMBOL_GPL(auxiliary_driver_unregister); >> >> -static int __init auxiliary_bus_init(void) >> +void __init auxiliary_bus_init(void) >> { >> - return bus_register(&auxiliary_bus_type); >> + WARN_ON(bus_register(&auxiliary_bus_type)); >> } >> - >> -static void __exit auxiliary_bus_exit(void) >> -{ >> - bus_unregister(&auxiliary_bus_type); >> -} >> - >> -module_init(auxiliary_bus_init); >> -module_exit(auxiliary_bus_exit); >> - >> -MODULE_LICENSE("GPL v2"); >> -MODULE_DESCRIPTION("Auxiliary Bus"); >> -MODULE_AUTHOR("David Ertman <david.m.ertman@intel.com>"); >> -MODULE_AUTHOR("Kiran Patil <kiran.patil@intel.com>"); >> diff --git a/drivers/base/init.c b/drivers/base/init.c >> index 908e6520e804..a9f57c22fb9e 100644 >> --- a/drivers/base/init.c >> +++ b/drivers/base/init.c >> @@ -32,6 +32,7 @@ void __init driver_init(void) >> */ >> of_core_init(); >> platform_bus_init(); >> + auxiliary_bus_init(); >> cpu_dev_init(); >> memory_dev_init(); >> container_dev_init(); >> -- >> 2.26.2 >> > This is already in my tree, you got an email about it. Do the module > removal as a separate patch as it has nothing to do with this one as the > code could never be built as a module, your patch did not change it, so > you are doing 2 different things here.
Ok I will send a separate patch.
> > {sigh} > > Intel owes me a new bottle of whisky.
Thank you for your patience, and I apologize for any future vexing. I can't speak for Intel, but I can certainly try to accommodate that at a future conference. :)
> > greg k-h
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