Fei Yang 73103c7f95 usb: gadget: f_fs: don't free buffer prematurely
The following kernel panic happens due to the io_data buffer gets deallocated
before the async io is completed. Add a check for the case where io_data buffer
should be deallocated by ffs_user_copy_worker.

[   41.663334] BUG: unable to handle kernel NULL pointer dereference at 0000000000000048
[   41.672099] #PF error: [normal kernel read fault]
[   41.677356] PGD 20c974067 P4D 20c974067 PUD 20c973067 PMD 0
[   41.683687] Oops: 0000 [#1] PREEMPT SMP
[   41.687976] CPU: 1 PID: 7 Comm: kworker/u8:0 Tainted: G     U            5.0.0-quilt-2e5dc0ac-00790-gd8c79f2-dirty #2
[   41.705309] Workqueue: adb ffs_user_copy_worker
[   41.705316] RIP: 0010:__vunmap+0x2a/0xc0
[   41.705318] Code: 0f 1f 44 00 00 48 85 ff 0f 84 87 00 00 00 55 f7 c7 ff 0f 00 00 48 89 e5 41 55 41 89 f5 41 54 53 48 89 fb 75 71 e8 56 d7 ff ff <4c> 8b 60 48 4d 85 e4 74 76 48 89 df e8 25 ff ff ff 45 85 ed 74 46
[   41.705320] RSP: 0018:ffffbc3a40053df0 EFLAGS: 00010286
[   41.705322] RAX: 0000000000000000 RBX: ffffbc3a406f1000 RCX: 0000000000000000
[   41.705323] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00000000ffffffff
[   41.705324] RBP: ffffbc3a40053e08 R08: 000000000001fb79 R09: 0000000000000037
[   41.705325] R10: ffffbc3a40053b68 R11: ffffbc3a40053cad R12: fffffffffffffff2
[   41.705326] R13: 0000000000000001 R14: 0000000000000000 R15: ffffffffffffffff
[   41.705328] FS:  0000000000000000(0000) GS:ffff9e2977a80000(0000) knlGS:0000000000000000
[   41.705329] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   41.705330] CR2: 0000000000000048 CR3: 000000020c994000 CR4: 00000000003406e0
[   41.705331] Call Trace:
[   41.705338]  vfree+0x50/0xb0
[   41.705341]  ffs_user_copy_worker+0xe9/0x1c0
[   41.705344]  process_one_work+0x19f/0x3e0
[   41.705348]  worker_thread+0x3f/0x3b0
[   41.829766]  kthread+0x12b/0x150
[   41.833371]  ? process_one_work+0x3e0/0x3e0
[   41.838045]  ? kthread_create_worker_on_cpu+0x70/0x70
[   41.843695]  ret_from_fork+0x3a/0x50
[   41.847689] Modules linked in: hci_uart bluetooth ecdh_generic rfkill_gpio dwc3_pci dwc3 snd_usb_audio mei_me tpm_crb snd_usbmidi_lib xhci_pci xhci_hcd mei tpm snd_hwdep cfg80211 snd_soc_skl snd_soc_skl_ipc snd_soc_sst_ipc snd_soc_sst_dsp snd_hda_ext_core snd_hda_core videobuf2_dma_sg crlmodule
[   41.876880] CR2: 0000000000000048
[   41.880584] ---[ end trace 2bc4addff0f2e673 ]---
[   41.891346] RIP: 0010:__vunmap+0x2a/0xc0
[   41.895734] Code: 0f 1f 44 00 00 48 85 ff 0f 84 87 00 00 00 55 f7 c7 ff 0f 00 00 48 89 e5 41 55 41 89 f5 41 54 53 48 89 fb 75 71 e8 56 d7 ff ff <4c> 8b 60 48 4d 85 e4 74 76 48 89 df e8 25 ff ff ff 45 85 ed 74 46
[   41.916740] RSP: 0018:ffffbc3a40053df0 EFLAGS: 00010286
[   41.922583] RAX: 0000000000000000 RBX: ffffbc3a406f1000 RCX: 0000000000000000
[   41.930563] RDX: 0000000000000001 RSI: 0000000000000001 RDI: 00000000ffffffff
[   41.938540] RBP: ffffbc3a40053e08 R08: 000000000001fb79 R09: 0000000000000037
[   41.946520] R10: ffffbc3a40053b68 R11: ffffbc3a40053cad R12: fffffffffffffff2
[   41.954502] R13: 0000000000000001 R14: 0000000000000000 R15: ffffffffffffffff
[   41.962482] FS:  0000000000000000(0000) GS:ffff9e2977a80000(0000) knlGS:0000000000000000
[   41.971536] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   41.977960] CR2: 0000000000000048 CR3: 000000020c994000 CR4: 00000000003406e0
[   41.985930] Kernel panic - not syncing: Fatal exception
[   41.991817] Kernel Offset: 0x16000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[   42.009525] Rebooting in 10 seconds..
[   52.014376] ACPI MEMORY or I/O RESET_REG.

Fixes: 772a7a724f69 ("usb: gadget: f_fs: Allow scatter-gather buffers")
Signed-off-by: Fei Yang <fei.yang@intel.com>
Reviewed-by: Manu Gautam <mgautam@codeaurora.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2019-05-03 09:12:53 +03:00
2019-04-20 12:20:58 -07:00
2019-04-20 12:20:58 -07:00
2019-04-20 12:55:23 -07:00
2019-04-16 15:38:07 +02:00
2019-04-02 18:12:44 -10:00
2019-03-06 14:18:59 -08:00
2019-03-10 17:48:21 -07:00
2019-04-20 10:43:37 -07:00
2019-04-21 10:45:57 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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