On Sun, 18 Sep 2022 15:01:11 +0200, Rondreis wrote: > > Hello, > > When fuzzing the Linux kernel driver v6.0-rc4, the following crash was > triggered. > > HEAD commit: 7e18e42e4b280c85b76967a9106a13ca61c16179 > git tree: upstream > > kernel config: https://pastebin.com/raw/xtrgsXP3 > C reproducer: https://pastebin.com/raw/w2sdQWYj > console output: https://pastebin.com/raw/Yyf7zw2d > > Basically, in the c reproducer, we use the gadget module to emulate > attaching a USB device(vendor id: 0x1bc7, product id: 0x1206, with the > midi function) and executing some simple sequence of system calls. > To reproduce this crash, we utilize a third-party library to emulate > the attaching process: https://github.com/linux-usb-gadgets/libusbgx. > Just clone this repository, install it, and compile the c > reproducer with ``` gcc crash.c -lusbgx -lconfig -o crash ``` will do > the trick. > > I would appreciate it if you have any idea how to solve this bug. Could you try the patch below? It looks like a simple double-free in the code. thanks, Takashi --- --- a/sound/core/init.c +++ b/sound/core/init.c @@ -178,10 +178,8 @@ int snd_card_new(struct device *parent, int idx, const char *xid, return -ENOMEM; err = snd_card_init(card, parent, idx, xid, module, extra_size); - if (err < 0) { - kfree(card); - return err; - } + if (err < 0) + return err; /* card is freed by error handler */ *card_ret = card; return 0; @@ -233,7 +231,7 @@ int snd_devm_card_new(struct device *parent, int idx, const char *xid, card->managed = true; err = snd_card_init(card, parent, idx, xid, module, extra_size); if (err < 0) { - devres_free(card); + devres_free(card); /* in managed mode, we need to free manually */ return err; }
