| Message ID | 20190708125050.3689133-1-arnd@arndb.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ath10k: work around uninitialized vht_pfr variable | expand |
On Mon, Jul 08, 2019 at 02:50:06PM +0200, Arnd Bergmann wrote: > As clang points out, the vht_pfr is assigned to a struct member > without being initialized in one case: > > drivers/net/wireless/ath/ath10k/mac.c:7528:7: error: variable 'vht_pfr' is used uninitialized whenever 'if' condition > is false [-Werror,-Wsometimes-uninitialized] > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7551:20: note: uninitialized use occurs here > arvif->vht_pfr = vht_pfr; > ^~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7528:3: note: remove the 'if' if its condition is always true > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7483:12: note: initialize the variable 'vht_pfr' to silence this warning > u8 vht_pfr; > > Add an explicit but probably incorrect initialization here. > I suspect we want a better fix here, but chose this approach to > illustrate the issue. Yup, I reached out to the maintainers when this issue first cropped up, should have taken your approach though. https://lore.kernel.org/lkml/20190702181837.GA118849@archlinux-epyc/ Initializing to zero is better than uninitialized. > > Fixes: 8b97b055dc9d ("ath10k: fix failure to set multiple fixed rate") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Hi Arnd, On Mon, Jul 8, 2019 at 5:50 AM Arnd Bergmann <arnd@arndb.de> wrote: > > As clang points out, the vht_pfr is assigned to a struct member > without being initialized in one case: > > drivers/net/wireless/ath/ath10k/mac.c:7528:7: error: variable 'vht_pfr' is used uninitialized whenever 'if' condition > is false [-Werror,-Wsometimes-uninitialized] > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7551:20: note: uninitialized use occurs here > arvif->vht_pfr = vht_pfr; > ^~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7528:3: note: remove the 'if' if its condition is always true > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7483:12: note: initialize the variable 'vht_pfr' to silence this warning > u8 vht_pfr; > > Add an explicit but probably incorrect initialization here. > I suspect we want a better fix here, but chose this approach to > illustrate the issue. > > Fixes: 8b97b055dc9d ("ath10k: fix failure to set multiple fixed rate") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > drivers/net/wireless/ath/ath10k/mac.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c > index e43a566eef77..0606416dc971 100644 > --- a/drivers/net/wireless/ath/ath10k/mac.c > +++ b/drivers/net/wireless/ath/ath10k/mac.c > @@ -7541,6 +7541,8 @@ static int ath10k_mac_op_set_bitrate_mask(struct ieee80211_hw *hw, > &vht_nss, > true); ^^ Technically, this call to ath10k_mac_bitrate_mask_get_single_rate() can fail to assign 'vht_pfr' as well. I can't immediately tell whether it provably will never hit the -EINVAL case, but if we do, then you'd have another uninitialized case. I *believe* it shouldn't fail, since we already pre-checked the VHT MCS lists for "exactly 1" rate. But it still seems like better code to pre-initialize and/or add error-handling, so we don't rely on that implicit proof. I'm not quite sure yet what the "better" answer should be for resolving this, but at a minimum, I think the above could be improved. Brian > update_bitrate_mask = false; > + } else { > + vht_pfr = 0; > } > > mutex_lock(&ar->conf_mutex); > -- > 2.20.0 >
Arnd Bergmann <arnd@arndb.de> writes: > As clang points out, the vht_pfr is assigned to a struct member > without being initialized in one case: > > drivers/net/wireless/ath/ath10k/mac.c:7528:7: error: variable 'vht_pfr' is used uninitialized whenever 'if' condition > is false [-Werror,-Wsometimes-uninitialized] > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7551:20: note: uninitialized use occurs here > arvif->vht_pfr = vht_pfr; > ^~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7528:3: note: remove the 'if' if its condition is always true > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7483:12: note: initialize the variable 'vht_pfr' to silence this warning > u8 vht_pfr; > > Add an explicit but probably incorrect initialization here. > I suspect we want a better fix here, but chose this approach to > illustrate the issue. > > Fixes: 8b97b055dc9d ("ath10k: fix failure to set multiple fixed rate") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> I'll queue this for v5.3.
Arnd Bergmann <arnd@arndb.de> wrote: > As clang points out, the vht_pfr is assigned to a struct member > without being initialized in one case: > > drivers/net/wireless/ath/ath10k/mac.c:7528:7: error: variable 'vht_pfr' is used uninitialized whenever 'if' condition > is false [-Werror,-Wsometimes-uninitialized] > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7551:20: note: uninitialized use occurs here > arvif->vht_pfr = vht_pfr; > ^~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7528:3: note: remove the 'if' if its condition is always true > if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, > ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > drivers/net/wireless/ath/ath10k/mac.c:7483:12: note: initialize the variable 'vht_pfr' to silence this warning > u8 vht_pfr; > > Add an explicit but probably incorrect initialization here. > I suspect we want a better fix here, but chose this approach to > illustrate the issue. > > Fixes: 8b97b055dc9d ("ath10k: fix failure to set multiple fixed rate") > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Patch applied to wireless-drivers.git, thanks. ff414f31ce37 ath10k: work around uninitialized vht_pfr variable
diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index e43a566eef77..0606416dc971 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -7541,6 +7541,8 @@ static int ath10k_mac_op_set_bitrate_mask(struct ieee80211_hw *hw, &vht_nss, true); update_bitrate_mask = false; + } else { + vht_pfr = 0; } mutex_lock(&ar->conf_mutex);
As clang points out, the vht_pfr is assigned to a struct member without being initialized in one case: drivers/net/wireless/ath/ath10k/mac.c:7528:7: error: variable 'vht_pfr' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/wireless/ath/ath10k/mac.c:7551:20: note: uninitialized use occurs here arvif->vht_pfr = vht_pfr; ^~~~~~~ drivers/net/wireless/ath/ath10k/mac.c:7528:3: note: remove the 'if' if its condition is always true if (!ath10k_mac_can_set_bitrate_mask(ar, band, mask, ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/net/wireless/ath/ath10k/mac.c:7483:12: note: initialize the variable 'vht_pfr' to silence this warning u8 vht_pfr; Add an explicit but probably incorrect initialization here. I suspect we want a better fix here, but chose this approach to illustrate the issue. Fixes: 8b97b055dc9d ("ath10k: fix failure to set multiple fixed rate") Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- drivers/net/wireless/ath/ath10k/mac.c | 2 ++ 1 file changed, 2 insertions(+)