Re: [PATCH 3/3] IB/hfi1: Don't attempt to free resources if initialization failed

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

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On Wed, Apr 20, 2016 at 06:05:36AM -0700, Dennis Dalessandro wrote:
> From: Mitko Haralanov <mitko.haralanov-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> 
> Attempting to free resources which have not been allocated and
> initialized properly led to the following kernel backtrace:
> 
>     BUG: unable to handle kernel NULL pointer dereference at           (null)
>     IP: [<ffffffffa09658fe>] unlock_exp_tids.isra.8+0x2e/0x120 [hfi1]
>     PGD 852a43067 PUD 85d4a6067 PMD 0
>     Oops: 0000 [#1] SMP
>     CPU: 0 PID: 2831 Comm: osu_bw Tainted: G          IO 3.12.18-wfr+ #1
>     task: ffff88085b15b540 ti: ffff8808588fe000 task.ti: ffff8808588fe000
>     RIP: 0010:[<ffffffffa09658fe>]  [<ffffffffa09658fe>] unlock_exp_tids.isra.8+0x2e/0x120 [hfi1]
>     RSP: 0018:ffff8808588ffde0  EFLAGS: 00010282
>     RAX: 0000000000000000 RBX: ffff880858a31800 RCX: 0000000000000000
>     RDX: ffff88085d971bc0 RSI: ffff880858a318f8 RDI: ffff880858a318c0
>     RBP: ffff8808588ffe20 R08: 0000000000000000 R09: 0000000000000000
>     R10: ffff88087ffd6f40 R11: 0000000001100348 R12: ffff880852900000
>     R13: ffff880858a318c0 R14: 0000000000000000 R15: ffff88085d971be8
>     FS:  00007f4674e83740(0000) GS:ffff88087f400000(0000) knlGS:0000000000000000
>     CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>     CR2: 0000000000000000 CR3: 000000085c377000 CR4: 00000000001407f0
>     Stack:
>      ffffffffa0941a71 ffff880858a318f8 ffff88085d971bc0 ffff880858a31800
>      ffff880852900000 ffff880858a31800 00000000003ffff7 ffff88085d971bc0
>      ffff8808588ffe60 ffffffffa09663fc ffff8808588ffe60 ffff880858a31800
>     Call Trace:
>      [<ffffffffa0941a71>] ? find_mmu_handler+0x51/0x70 [hfi1]
>      [<ffffffffa09663fc>] hfi1_user_exp_rcv_free+0x6c/0x120 [hfi1]
>      [<ffffffffa0932809>] hfi1_file_close+0x1a9/0x340 [hfi1]
>      [<ffffffff8116c189>] __fput+0xe9/0x270
>      [<ffffffff8116c35e>] ____fput+0xe/0x10
>      [<ffffffff81065707>] task_work_run+0xa7/0xe0
>      [<ffffffff81002969>] do_notify_resume+0x59/0x80
>      [<ffffffff814ffc1a>] int_signal+0x12/0x17
> 
> This commit re-arranges the context initialization code in a way that
> would allow for context event flags to be used to determine whether
> the context has been successfully initialized.
> 
> In turn, this can be used to skip the resource de-allocation if they
> were never allocated in the first place.
> 
> Fixes: 3abb33ac6521 ("staging/hfi1: Add TID cache receive init and free funcs")
> Reviewed-by: Dennis Dalessandro <dennis.dalessandro-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
> Signed-off-by: Mitko Haralanov <mitko.haralanov-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

Reviewed-by: Leon Romanovsky <leonro-VPRAkNaXOzUU04JRNCRQjg@public.gmane.org

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