| Message ID | 20230911162706.2856910-1-yu.c.chen@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | usb: typec: ucsi: Release debugfs only if it has been allocated | expand |
Hi Greg, thanks for your time, On 2023-09-11 at 20:59:18 +0200, Greg Kroah-Hartman wrote: > On Tue, Sep 12, 2023 at 12:27:06AM +0800, Chen Yu wrote: > > The following NULL pointer exception was found during boot up: > > > > calling ucsi_acpi_platform_driver_init+0x0/0xff0 [ucsi_acpi] @ 394 > > initcall mac_hid_init+0x0/0xff0 [mac_hid] returned 0 after 5 usecs > > BUG: kernel NULL pointer dereference, address: 0000000000000020 > > Call Trace: > > ? ucsi_debugfs_unregister+0x15/0x30 [typec_ucsi] > > ucsi_destroy+0x17/0x30 [typec_ucsi] > > ucsi_acpi_probe+0x1d5/0x230 [ucsi_acpi] > > > > It is possible that ucsi_acpi_probe() fails to install the notifier, > > and calls ucsi_destroy() to release the resource. However at that > > moment the debugfs has not been registered yet, thus the NULL pointer > > exception is triggered. Add the check for debugfs pointer. > > > > Fixes: Commit df0383ffad64 ("usb: typec: ucsi: Add debugfs for ucsi commands") > > Incorrect format :( > Ah, the 'Commit' was incorrectly added. > > Signed-off-by: Chen Yu <yu.c.chen@intel.com> > > --- > > drivers/usb/typec/ucsi/debugfs.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/usb/typec/ucsi/debugfs.c b/drivers/usb/typec/ucsi/debugfs.c > > index 0c7bf88d4a7f..55533dc3d539 100644 > > --- a/drivers/usb/typec/ucsi/debugfs.c > > +++ b/drivers/usb/typec/ucsi/debugfs.c > > @@ -84,7 +84,8 @@ void ucsi_debugfs_register(struct ucsi *ucsi) > > > > void ucsi_debugfs_unregister(struct ucsi *ucsi) > > { > > - debugfs_remove_recursive(ucsi->debugfs->dentry); > > + if (ucsi->debugfs) > > + debugfs_remove_recursive(ucsi->debugfs->dentry); > > kfree(ucsi->debugfs); > > } > > What's wrong with this patch instead: > https://lore.kernel.org/all/20230906084842.1922052-1-heikki.krogerus@linux.intel.com/ > Thanks for this link, I'll patch my kernel using above version. thanks, Chenyu
diff --git a/drivers/usb/typec/ucsi/debugfs.c b/drivers/usb/typec/ucsi/debugfs.c index 0c7bf88d4a7f..55533dc3d539 100644 --- a/drivers/usb/typec/ucsi/debugfs.c +++ b/drivers/usb/typec/ucsi/debugfs.c @@ -84,7 +84,8 @@ void ucsi_debugfs_register(struct ucsi *ucsi) void ucsi_debugfs_unregister(struct ucsi *ucsi) { - debugfs_remove_recursive(ucsi->debugfs->dentry); + if (ucsi->debugfs) + debugfs_remove_recursive(ucsi->debugfs->dentry); kfree(ucsi->debugfs); }
The following NULL pointer exception was found during boot up: calling ucsi_acpi_platform_driver_init+0x0/0xff0 [ucsi_acpi] @ 394 initcall mac_hid_init+0x0/0xff0 [mac_hid] returned 0 after 5 usecs BUG: kernel NULL pointer dereference, address: 0000000000000020 Call Trace: ? ucsi_debugfs_unregister+0x15/0x30 [typec_ucsi] ucsi_destroy+0x17/0x30 [typec_ucsi] ucsi_acpi_probe+0x1d5/0x230 [ucsi_acpi] It is possible that ucsi_acpi_probe() fails to install the notifier, and calls ucsi_destroy() to release the resource. However at that moment the debugfs has not been registered yet, thus the NULL pointer exception is triggered. Add the check for debugfs pointer. Fixes: Commit df0383ffad64 ("usb: typec: ucsi: Add debugfs for ucsi commands") Signed-off-by: Chen Yu <yu.c.chen@intel.com> --- drivers/usb/typec/ucsi/debugfs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)