diff options
| author | Owen Gu <guhuinan@xiaomi.com> | 2025-09-15 17:29:07 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-09-17 12:42:47 +0200 |
| commit | cfd6f1a7b42f62523c96d9703ef32b0dbc495ba4 (patch) | |
| tree | db7cc6ca9077a42195981876d6b4e223ca1629c7 | |
| parent | 45fe729be9a6be326a1ca25af82d34de32ba2ce8 (diff) | |
usb: gadget: f_fs: Fix epfile null pointer access after ep enable.
A race condition occurs when ffs_func_eps_enable() runs concurrently
with ffs_data_reset(). The ffs_data_clear() called in ffs_data_reset()
sets ffs->epfiles to NULL before resetting ffs->eps_count to 0, leading
to a NULL pointer dereference when accessing epfile->ep in
ffs_func_eps_enable() after successful usb_ep_enable().
The ffs->epfiles pointer is set to NULL in both ffs_data_clear() and
ffs_data_close() functions, and its modification is protected by the
spinlock ffs->eps_lock. And the whole ffs_func_eps_enable() function
is also protected by ffs->eps_lock.
Thus, add NULL pointer handling for ffs->epfiles in the
ffs_func_eps_enable() function to fix issues
Signed-off-by: Owen Gu <guhuinan@xiaomi.com>
Link: https://lore.kernel.org/r/20250915092907.17802-1-guhuinan@xiaomi.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/gadget/function/f_fs.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/usb/gadget/function/f_fs.c b/drivers/usb/gadget/function/f_fs.c index 08a251df20c4..04058261cdd0 100644 --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -2407,7 +2407,12 @@ static int ffs_func_eps_enable(struct ffs_function *func) ep = func->eps; epfile = ffs->epfiles; count = ffs->eps_count; - while(count--) { + if (!epfile) { + ret = -ENOMEM; + goto done; + } + + while (count--) { ep->ep->driver_data = ep; ret = config_ep_by_speed(func->gadget, &func->function, ep->ep); @@ -2431,6 +2436,7 @@ static int ffs_func_eps_enable(struct ffs_function *func) } wake_up_interruptible(&ffs->wait); +done: spin_unlock_irqrestore(&func->ffs->eps_lock, flags); return ret; |