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Message-Id: <20240223054809.2379-1-quic_selvaras@quicinc.com>
Date: Thu, 22 Feb 2024 21:48:09 -0800
From: Selvarasu Ganesan <quic_selvaras@...cinc.com>
To: gregkh@...uxfoundation.org, brauner@...nel.org, axboe@...nel.dk,
jack@...e.cz, jlayton@...nel.org, keescook@...omium.org,
peter@...sgaard.com, hayama@...eo.co.jp, dmantipov@...dex.ru,
quic_linyyuan@...cinc.com
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
quic_ppratap@...cinc.com, quic_wcheng@...cinc.com,
quic_jackp@...cinc.com, Selvarasu Ganesan <quic_selvaras@...cinc.com>
Subject: [PATCH] usb: gadget: f_fs: Fix NULL pointer dereference in ffs_epfile_async_io_complete()
In scenarios of continuous and parallel usage of multiple FFS interfaces
and concurrent adb operations (e.g., adb root, adb reboot), there's a
chance that ffs_epfile_async_io_complete() might be processed after
ffs_epfile_release(). This could lead to a NULL pointer dereference of
ffs when accessing the ffs pointer in ffs_epfile_async_io_complete(), as
ffs is freed as part of ffs_epfile_release(). This epfile release is
part of file operation and is triggered when user space daemons restart
themselves or a reboot is initiated.
Fix this issue by adding a NULL pointer check for ffs in
ffs_epfile_async_io_complete().
[ 9981.393115] Unable to handle kernel NULL pointer dereference at virtual address 00000000000001e0
[ 9981.402854] Mem abort info:
..
[ 9981.532540] Hardware name: Qualcomm Technologies,
[ 9981.540579] pstate: 204000c5 (nzCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 9981.548438] pc : ffs_epfile_async_io_complete+0x38/0x4c
[ 9981.554529] lr : usb_gadget_giveback_request+0x30/0xd0
..
[ 9981.645057] Call trace:
[ 9981.648282] ffs_epfile_async_io_complete+0x38/0x4c
[ 9981.654004] usb_gadget_giveback_request+0x30/0xd0
[ 9981.659637] dwc3_gadget_endpoint_trbs_complete+0x1a8/0x48c
[ 9981.666074] dwc3_process_event_entry+0x378/0x648
[ 9981.671622] dwc3_process_event_buf+0x6c/0x288
[ 9981.676903] dwc3_thread_interrupt+0x3c/0x68
[ 9981.682003] irq_thread_fn+0x2c/0x8c
[ 9981.686388] irq_thread+0x198/0x2ac
[ 9981.690685] kthread+0x154/0x218
[ 9981.694717] ret_from_fork+0x10/0x20
Signed-off-by: Selvarasu Ganesan <quic_selvaras@...cinc.com>
---
drivers/usb/gadget/function/f_fs.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c
index be3851cffb73..d8c8e88628f9 100644
--- a/drivers/usb/gadget/function/f_fs.c
+++ b/drivers/usb/gadget/function/f_fs.c
@@ -849,7 +849,9 @@ static void ffs_epfile_async_io_complete(struct usb_ep *_ep,
usb_ep_free_request(_ep, req);
INIT_WORK(&io_data->work, ffs_user_copy_worker);
- queue_work(ffs->io_completion_wq, &io_data->work);
+
+ if (ffs && ffs->io_completion_wq)
+ queue_work(ffs->io_completion_wq, &io_data->work);
}
static void __ffs_epfile_read_buffer_free(struct ffs_epfile *epfile)
--
2.17.1
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