From: Nathan Chancellor <nathan@xxxxxxxxxx> commit 1696ec8654016dad3b1baf6c024303e584400453 upstream. When booting a kernel with CONFIG_MISDN_DSP=y and CONFIG_CFI_CLANG=y, there is a failure when dsp_cmx_send() is called indirectly from call_timer_fn(): [ 0.371412] CFI failure at call_timer_fn+0x2f/0x150 (target: dsp_cmx_send+0x0/0x530; expected type: 0x92ada1e9) The function pointer prototype that call_timer_fn() expects is void (*fn)(struct timer_list *) whereas dsp_cmx_send() has a parameter type of 'void *', which causes the control flow integrity checks to fail because the parameter types do not match. Change dsp_cmx_send()'s parameter type to be 'struct timer_list' to match the expected prototype. The argument is unused anyways, so this has no functional change, aside from avoiding the CFI failure. Reported-by: kernel test robot <oliver.sang@xxxxxxxxx> Closes: https://lore.kernel.org/oe-lkp/202308020936.58787e6c-oliver.sang@xxxxxxxxx Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx> Reviewed-by: Sami Tolvanen <samitolvanen@xxxxxxxxxx> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx> Fixes: e313ac12eb13 ("mISDN: Convert timers to use timer_setup()") Link: https://lore.kernel.org/r/20230802-fix-dsp_cmx_send-cfi-failure-v1-1-2f2e79b0178d@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/isdn/mISDN/dsp.h | 2 +- drivers/isdn/mISDN/dsp_cmx.c | 2 +- drivers/isdn/mISDN/dsp_core.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) --- a/drivers/isdn/mISDN/dsp.h +++ b/drivers/isdn/mISDN/dsp.h @@ -247,7 +247,7 @@ extern void dsp_cmx_hardware(struct dsp_ extern int dsp_cmx_conf(struct dsp *dsp, u32 conf_id); extern void dsp_cmx_receive(struct dsp *dsp, struct sk_buff *skb); extern void dsp_cmx_hdlc(struct dsp *dsp, struct sk_buff *skb); -extern void dsp_cmx_send(void *arg); +extern void dsp_cmx_send(struct timer_list *arg); extern void dsp_cmx_transmit(struct dsp *dsp, struct sk_buff *skb); extern int dsp_cmx_del_conf_member(struct dsp *dsp); extern int dsp_cmx_del_conf(struct dsp_conf *conf); --- a/drivers/isdn/mISDN/dsp_cmx.c +++ b/drivers/isdn/mISDN/dsp_cmx.c @@ -1625,7 +1625,7 @@ static u16 dsp_count; /* last sample cou static int dsp_count_valid; /* if we have last sample count */ void -dsp_cmx_send(void *arg) +dsp_cmx_send(struct timer_list *arg) { struct dsp_conf *conf; struct dsp_conf_member *member; --- a/drivers/isdn/mISDN/dsp_core.c +++ b/drivers/isdn/mISDN/dsp_core.c @@ -1195,7 +1195,7 @@ static int __init dsp_init(void) } /* set sample timer */ - timer_setup(&dsp_spl_tl, (void *)dsp_cmx_send, 0); + timer_setup(&dsp_spl_tl, dsp_cmx_send, 0); dsp_spl_tl.expires = jiffies + dsp_tics; dsp_spl_jiffies = dsp_spl_tl.expires; add_timer(&dsp_spl_tl);
