870201f95f
As part of ib_uverbs_remove_one which might be triggered upon
reset flow, we trigger IB_EVENT_DEVICE_FATAL event to userspace
application.
If device was removed after uverbs fd was opened but before
ib_uverbs_get_context was called, the event file will be accessed
before it was allocated, result in NULL pointer dereference:
[ 72.325873] BUG: unable to handle kernel NULL pointer dereference at (null)
...
[ 72.325984] IP: _raw_spin_lock_irqsave+0x22/0x40
[ 72.327123] Call Trace:
[ 72.327168] ib_uverbs_async_handler.isra.8+0x2e/0x160 [ib_uverbs]
[ 72.327216] ? synchronize_srcu_expedited+0x27/0x30
[ 72.327269] ib_uverbs_remove_one+0x120/0x2c0 [ib_uverbs]
[ 72.327330] ib_unregister_device+0xd0/0x180 [ib_core]
[ 72.327373] mlx5_ib_remove+0x74/0x140 [mlx5_ib]
[ 72.327422] mlx5_remove_device+0xfb/0x110 [mlx5_core]
[ 72.327466] mlx5_unregister_interface+0x3c/0xa0 [mlx5_core]
[ 72.327509] mlx5_ib_cleanup+0x10/0x962 [mlx5_ib]
[ 72.327546] SyS_delete_module+0x155/0x230
[ 72.328472] ? exit_to_usermode_loop+0x70/0xa6
[ 72.329370] do_syscall_64+0x54/0xc0
[ 72.330262] entry_SYSCALL64_slow_path+0x25/0x25
Fix it by checking that user context was allocated before
trigger the event.
Fixes:
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| .. | ||
| core | ||
| hw | ||
| sw | ||
| ulp | ||
| Kconfig | ||
| Makefile | ||