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fc9823eddc
In one of the SMMU faults (NULL Pointer derefernce) the following
race condition was observed and func->interfaces_nums was being
accessed for f_fs interface after it was unbinded resulting in a
crash.
Thread-1 Thread-2
ffs_func_req_match+0x68/0xc8
drain_workqueue+0xac
gsi_unbind[usb_f_gsi]+0x64
purge_configs_funcs+0xb4
configfs_composite_unbind+0xac
usb_gadget_remove_driver+0xac
usb_gadget_unregister_driver+0xd8
gadget_dev_desc_UDC_store+0x114
android_setup+0x164/0x2a8
dwc3_ep0_inspect_setup+0x100/0x440
dwc3_ep0_interrupt+0xac/0x300
dwc3_process_event_entry+0x80/0x724
dwc3_process_event_buf+0x80/0x434
dwc3_thread_interrupt+0x60/0x124
irq_thread_fn+0x54/0xe4
irq_thread+0x3a4/0x6ec
kthread+0x188/0x1ec
ret_from_fork+0x10/0x20
The events happened in order are as follows:
We got a setup packet for ffs interface and was passed to android
setup callback from ep0.c. As part of the delegate request, the
dwc->lock is released.
At this instant a composition switch occurred and as per traces
and crash dumps:
1. UDC Stop was done successfully. So run stop is set to '0'
2. Composite disconnect was done and ep disable for all ep's is done
gadget->connected = FALSE
3. Async callbacks disabled
dwc->aysnc_callbacks = FALSE
4. composite unbind is going on and the ffs interface in question is
unbinded
udc->driver != NULL
(as per crash dump indicating that unbind is in progress)
5. Purge configs was ongoing because as per crash dumps:
otg_desc[0] = NULL;
cdev->os_desc_req->buf is not NULL
(configfs_composite_unbind is going on, but composite_dev_cleanup
not yet done)
As per the traces:
23.794712: dwc3_event event=49216 ep0state=1 str=
23.794909: dwc3_ctrl_req bRequestType=161 bRequest=1 wValue=0
wIndex=2 wLength=4096
23.799740: usb_gadget_disconnect speed=5 max_speed=6 state=7
mA=0 deactivated=0 connected=0 ret=0
This indicated that android setup came first followed by composite
disconnect. Since the dwc->lock was released by delegate_request,
soft disconnect gets unblocked and runs parallel to composite setup.
After this, there is no check in path of composite setup
indicating unbind happened and bail out is necessary instead of
executing any function ops.
Protect composite_setup (as part of android_setup) in a spinlock
to block composite_disconnect/unbind running in parallel.
Moreover, in the configfs counterpart of android_setup (configfs_
composite_stetup), the composite_setup call is done with spinlock
held.
It is only the android_setup missing this lock.
Bug: 280548269
Fixes: 7a160e2b96 ("ANDROID: usb: gadget: configfs: Add Uevent to notify userspace")
Change-Id: Id245e9f72801541689fcb185ba0459824bfb3904
Signed-off-by: Krishna Kurapati <quic_kriskura@quicinc.com>
(cherry picked from commit 9ad803f257a8eb50a52c19a4cf33690cf1b85575)
How do I submit patches to Android Common Kernels
-
BEST: Make all of your changes to upstream Linux. If appropriate, backport to the stable releases. These patches will be merged automatically in the corresponding common kernels. If the patch is already in upstream Linux, post a backport of the patch that conforms to the patch requirements below.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
EXPORT_SYMBOL_GPL()require an in-tree modular driver that uses the symbol -- so include the new driver or changes to an existing driver in the same patchset as the export. - When sending patches upstream, the commit message must contain a clear case for why the patch is needed and beneficial to the community. Enabling out-of-tree drivers or functionality is not not a persuasive case.
- Do not send patches upstream that contain only symbol exports. To be considered for upstream Linux,
additions of
-
LESS GOOD: Develop your patches out-of-tree (from an upstream Linux point-of-view). Unless these are fixing an Android-specific bug, these are very unlikely to be accepted unless they have been coordinated with kernel-team@android.com. If you want to proceed, post a patch that conforms to the patch requirements below.
Common Kernel patch requirements
- All patches must conform to the Linux kernel coding standards and pass
scripts/checkpatch.pl - Patches shall not break gki_defconfig or allmodconfig builds for arm, arm64, x86, x86_64 architectures (see https://source.android.com/setup/build/building-kernels)
- If the patch is not merged from an upstream branch, the subject must be tagged with the type of patch:
UPSTREAM:,BACKPORT:,FROMGIT:,FROMLIST:, orANDROID:. - All patches must have a
Change-Id:tag (see https://gerrit-review.googlesource.com/Documentation/user-changeid.html) - If an Android bug has been assigned, there must be a
Bug:tag. - All patches must have a
Signed-off-by:tag by the author and the submitter
Additional requirements are listed below based on patch type
Requirements for backports from mainline Linux: UPSTREAM:, BACKPORT:
- If the patch is a cherry-pick from Linux mainline with no changes at all
- tag the patch subject with
UPSTREAM:. - add upstream commit information with a
(cherry picked from commit ...)line - Example:
- if the upstream commit message is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
UPSTREAM: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch requires any changes from the upstream version, tag the patch with
BACKPORT:instead ofUPSTREAM:.- use the same tags as
UPSTREAM: - add comments about the changes under the
(cherry picked from commit ...)line - Example:
- use the same tags as
BACKPORT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
(cherry picked from commit c31e73121f4c1ec41143423ac6ce3ce6dafdcec1)
[joe: Resolved minor conflict in drivers/foo/bar.c ]
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for other backports: FROMGIT:, FROMLIST:,
- If the patch has been merged into an upstream maintainer tree, but has not yet
been merged into Linux mainline
- tag the patch subject with
FROMGIT: - add info on where the patch came from as
(cherry picked from commit <sha1> <repo> <branch>). This must be a stable maintainer branch (not rebased, so don't uselinux-nextfor example). - if changes were required, use
BACKPORT: FROMGIT: - Example:
- if the commit message in the maintainer tree is
- tag the patch subject with
important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
- then Joe Smith would upload the patch for the common kernel as
FROMGIT: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
(cherry picked from commit 878a2fd9de10b03d11d2f622250285c7e63deace
https://git.kernel.org/pub/scm/linux/kernel/git/foo/bar.git test-branch)
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch has been submitted to LKML, but not accepted into any maintainer tree
- tag the patch subject with
FROMLIST: - add a
Link:tag with a link to the submittal on lore.kernel.org - add a
Bug:tag with the Android bug (required for patches not accepted into a maintainer tree) - if changes were required, use
BACKPORT: FROMLIST: - Example:
- tag the patch subject with
FROMLIST: important patch from upstream
This is the detailed description of the important patch
Signed-off-by: Fred Jones <fred.jones@foo.org>
Bug: 135791357
Link: https://lore.kernel.org/lkml/20190619171517.GA17557@someone.com/
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
Requirements for Android-specific patches: ANDROID:
- If the patch is fixing a bug to Android-specific code
- tag the patch subject with
ANDROID: - add a
Fixes:tag that cites the patch with the bug - Example:
- tag the patch subject with
ANDROID: fix android-specific bug in foobar.c
This is the detailed description of the important fix
Fixes: 1234abcd2468 ("foobar: add cool feature")
Change-Id: I4caaaa566ea080fa148c5e768bb1a0b6f7201c01
Signed-off-by: Joe Smith <joe.smith@foo.org>
- If the patch is a new feature
- tag the patch subject with
ANDROID: - add a
Bug:tag with the Android bug (required for android-specific features)
- tag the patch subject with