| Message ID | 1607108991-31948-1-git-send-email-manafm@codeaurora.org (mailing list archive) |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | Zhang Rui |
| Headers | show |
| Series | drivers: thermal: Add NULL pointer check before using cooling device stats | expand |
On 04/12/2020 20:09, Manaf Meethalavalappu Pallikunhi wrote: > There is a possible chance that some cooling device stats buffer > allocation fails due to very high cooling device max state value. > Later cooling device update or cooling stats sysfs will try to > access stats data for the same cooling device. It will lead to > NULL pointer dereference issue. > > Add a NULL pointer check before accessing thermal cooling device > stats data. It fixes the following bug Why not create the 'stats' dir if the setup fails ? > [ 26.812833] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 > [ 27.122960] Call trace: > [ 27.122963] do_raw_spin_lock+0x18/0xe8 > [ 27.122966] _raw_spin_lock+0x24/0x30 > [ 27.128157] thermal_cooling_device_stats_update+0x24/0x98 > [ 27.128162] cur_state_store+0x88/0xb8 > [ 27.128166] dev_attr_store+0x40/0x58 > [ 27.128169] sysfs_kf_write+0x50/0x68 > [ 27.133358] kernfs_fop_write+0x12c/0x1c8 > [ 27.133362] __vfs_write+0x54/0x160 > [ 27.152297] vfs_write+0xcc/0x188 > [ 27.157132] ksys_write+0x78/0x108 > [ 27.162050] ksys_write+0xf8/0x108 > [ 27.166968] __arm_smccc_hvc+0x158/0x4b0 > [ 27.166973] __arm_smccc_hvc+0x9c/0x4b0 > [ 27.186005] el0_svc+0x8/0xc > > Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org> > --- > drivers/thermal/thermal_sysfs.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index 473449b..a5e4855 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -827,6 +827,9 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev, > { > struct cooling_dev_stats *stats = cdev->stats; > > + if (!stats) > + return; > + > spin_lock(&stats->lock); > > if (stats->state == new_state) > @@ -848,6 +851,9 @@ static ssize_t total_trans_show(struct device *dev, > struct cooling_dev_stats *stats = cdev->stats; > int ret; > > + if (!stats) > + return -ENODEV; > + > spin_lock(&stats->lock); > ret = sprintf(buf, "%u\n", stats->total_trans); > spin_unlock(&stats->lock); > @@ -864,6 +870,9 @@ time_in_state_ms_show(struct device *dev, struct device_attribute *attr, > ssize_t len = 0; > int i; > > + if (!stats) > + return -ENODEV; > + > spin_lock(&stats->lock); > update_time_in_state(stats); > > @@ -882,8 +891,12 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf, > { > struct thermal_cooling_device *cdev = to_cooling_device(dev); > struct cooling_dev_stats *stats = cdev->stats; > - int i, states = stats->max_states; > + int i, states; > + > + if (!stats) > + return -ENODEV; > > + states = stats->max_states; > spin_lock(&stats->lock); > > stats->total_trans = 0; > @@ -907,6 +920,9 @@ static ssize_t trans_table_show(struct device *dev, > ssize_t len = 0; > int i, j; > > + if (!stats) > + return -ENODEV; > + > len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n"); > len += snprintf(buf + len, PAGE_SIZE - len, " : "); > for (i = 0; i < stats->max_states; i++) { >
On 04/12/2020 20:09, Manaf Meethalavalappu Pallikunhi wrote: > There is a possible chance that some cooling device stats buffer > allocation fails due to very high cooling device max state value. > Later cooling device update or cooling stats sysfs will try to > access stats data for the same cooling device. It will lead to > NULL pointer dereference issue. > > Add a NULL pointer check before accessing thermal cooling device > stats data. It fixes the following bug > > [ 26.812833] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 > [ 27.122960] Call trace: > [ 27.122963] do_raw_spin_lock+0x18/0xe8 > [ 27.122966] _raw_spin_lock+0x24/0x30 > [ 27.128157] thermal_cooling_device_stats_update+0x24/0x98 > [ 27.128162] cur_state_store+0x88/0xb8 > [ 27.128166] dev_attr_store+0x40/0x58 > [ 27.128169] sysfs_kf_write+0x50/0x68 > [ 27.133358] kernfs_fop_write+0x12c/0x1c8 > [ 27.133362] __vfs_write+0x54/0x160 > [ 27.152297] vfs_write+0xcc/0x188 > [ 27.157132] ksys_write+0x78/0x108 > [ 27.162050] ksys_write+0xf8/0x108 > [ 27.166968] __arm_smccc_hvc+0x158/0x4b0 > [ 27.166973] __arm_smccc_hvc+0x9c/0x4b0 > [ 27.186005] el0_svc+0x8/0xc > > Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org> The only place where it can crash is when the thermal_cooling_device_stats_update() function is called. The other places in show*/store* in the stats directory are inaccessible as the sysfs entry is not showed up due to the thermal_cooling_device_stats_setup() failing. It would have been nice if the thermal_cooling_device_stats_update() was not called at all but I don't see how we can do that without static keys which is overkill for a degraded mode. I guess having the kzallocation warning in the console output is enough to warn the user the system is working without the stats for the cooling device. That should not prevent the system functioning. Can you resend with the check in thermal_cooling_device_stats_update() only? Thanks -- Daniel > --- > drivers/thermal/thermal_sysfs.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c > index 473449b..a5e4855 100644 > --- a/drivers/thermal/thermal_sysfs.c > +++ b/drivers/thermal/thermal_sysfs.c > @@ -827,6 +827,9 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev, > { > struct cooling_dev_stats *stats = cdev->stats; > > + if (!stats) > + return; > + > spin_lock(&stats->lock); > > if (stats->state == new_state) > @@ -848,6 +851,9 @@ static ssize_t total_trans_show(struct device *dev, > struct cooling_dev_stats *stats = cdev->stats; > int ret; > > + if (!stats) > + return -ENODEV; > + > spin_lock(&stats->lock); > ret = sprintf(buf, "%u\n", stats->total_trans); > spin_unlock(&stats->lock); > @@ -864,6 +870,9 @@ time_in_state_ms_show(struct device *dev, struct device_attribute *attr, > ssize_t len = 0; > int i; > > + if (!stats) > + return -ENODEV; > + > spin_lock(&stats->lock); > update_time_in_state(stats); > > @@ -882,8 +891,12 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf, > { > struct thermal_cooling_device *cdev = to_cooling_device(dev); > struct cooling_dev_stats *stats = cdev->stats; > - int i, states = stats->max_states; > + int i, states; > + > + if (!stats) > + return -ENODEV; > > + states = stats->max_states; > spin_lock(&stats->lock); > > stats->total_trans = 0; > @@ -907,6 +920,9 @@ static ssize_t trans_table_show(struct device *dev, > ssize_t len = 0; > int i, j; > > + if (!stats) > + return -ENODEV; > + > len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n"); > len += snprintf(buf + len, PAGE_SIZE - len, " : "); > for (i = 0; i < stats->max_states; i++) { >
On 2020-12-05 16:42, Daniel Lezcano wrote: > On 04/12/2020 20:09, Manaf Meethalavalappu Pallikunhi wrote: >> There is a possible chance that some cooling device stats buffer >> allocation fails due to very high cooling device max state value. >> Later cooling device update or cooling stats sysfs will try to >> access stats data for the same cooling device. It will lead to >> NULL pointer dereference issue. >> >> Add a NULL pointer check before accessing thermal cooling device >> stats data. It fixes the following bug >> >> [ 26.812833] Unable to handle kernel NULL pointer dereference at >> virtual address 0000000000000004 >> [ 27.122960] Call trace: >> [ 27.122963] do_raw_spin_lock+0x18/0xe8 >> [ 27.122966] _raw_spin_lock+0x24/0x30 >> [ 27.128157] thermal_cooling_device_stats_update+0x24/0x98 >> [ 27.128162] cur_state_store+0x88/0xb8 >> [ 27.128166] dev_attr_store+0x40/0x58 >> [ 27.128169] sysfs_kf_write+0x50/0x68 >> [ 27.133358] kernfs_fop_write+0x12c/0x1c8 >> [ 27.133362] __vfs_write+0x54/0x160 >> [ 27.152297] vfs_write+0xcc/0x188 >> [ 27.157132] ksys_write+0x78/0x108 >> [ 27.162050] ksys_write+0xf8/0x108 >> [ 27.166968] __arm_smccc_hvc+0x158/0x4b0 >> [ 27.166973] __arm_smccc_hvc+0x9c/0x4b0 >> [ 27.186005] el0_svc+0x8/0xc >> >> Signed-off-by: Manaf Meethalavalappu Pallikunhi >> <manafm@codeaurora.org> > > The only place where it can crash is when the > thermal_cooling_device_stats_update() function is called. > > The other places in show*/store* in the stats directory are > inaccessible > as the sysfs entry is not showed up due to the > thermal_cooling_device_stats_setup() failing. > > It would have been nice if the thermal_cooling_device_stats_update() > was > not called at all but I don't see how we can do that without static > keys > which is overkill for a degraded mode. > > I guess having the kzallocation warning in the console output is enough > to warn the user the system is working without the stats for the > cooling > device. That should not prevent the system functioning. > > Can you resend with the check in thermal_cooling_device_stats_update() > only? > > Thanks > > -- Daniel Thanks for your review, I double checked it, yes, no need to add NULL check in stats sysfs show*/store* functions. I will update this in V2 Thanks Manaf > > >> --- >> drivers/thermal/thermal_sysfs.c | 18 +++++++++++++++++- >> 1 file changed, 17 insertions(+), 1 deletion(-) >> >> diff --git a/drivers/thermal/thermal_sysfs.c >> b/drivers/thermal/thermal_sysfs.c >> index 473449b..a5e4855 100644 >> --- a/drivers/thermal/thermal_sysfs.c >> +++ b/drivers/thermal/thermal_sysfs.c >> @@ -827,6 +827,9 @@ void thermal_cooling_device_stats_update(struct >> thermal_cooling_device *cdev, >> { >> struct cooling_dev_stats *stats = cdev->stats; >> >> + if (!stats) >> + return; >> + >> spin_lock(&stats->lock); >> >> if (stats->state == new_state) >> @@ -848,6 +851,9 @@ static ssize_t total_trans_show(struct device >> *dev, >> struct cooling_dev_stats *stats = cdev->stats; >> int ret; >> >> + if (!stats) >> + return -ENODEV; >> + >> spin_lock(&stats->lock); >> ret = sprintf(buf, "%u\n", stats->total_trans); >> spin_unlock(&stats->lock); >> @@ -864,6 +870,9 @@ time_in_state_ms_show(struct device *dev, struct >> device_attribute *attr, >> ssize_t len = 0; >> int i; >> >> + if (!stats) >> + return -ENODEV; >> + >> spin_lock(&stats->lock); >> update_time_in_state(stats); >> >> @@ -882,8 +891,12 @@ reset_store(struct device *dev, struct >> device_attribute *attr, const char *buf, >> { >> struct thermal_cooling_device *cdev = to_cooling_device(dev); >> struct cooling_dev_stats *stats = cdev->stats; >> - int i, states = stats->max_states; >> + int i, states; >> + >> + if (!stats) >> + return -ENODEV; >> >> + states = stats->max_states; >> spin_lock(&stats->lock); >> >> stats->total_trans = 0; >> @@ -907,6 +920,9 @@ static ssize_t trans_table_show(struct device >> *dev, >> ssize_t len = 0; >> int i, j; >> >> + if (!stats) >> + return -ENODEV; >> + >> len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n"); >> len += snprintf(buf + len, PAGE_SIZE - len, " : "); >> for (i = 0; i < stats->max_states; i++) { >>
diff --git a/drivers/thermal/thermal_sysfs.c b/drivers/thermal/thermal_sysfs.c index 473449b..a5e4855 100644 --- a/drivers/thermal/thermal_sysfs.c +++ b/drivers/thermal/thermal_sysfs.c @@ -827,6 +827,9 @@ void thermal_cooling_device_stats_update(struct thermal_cooling_device *cdev, { struct cooling_dev_stats *stats = cdev->stats; + if (!stats) + return; + spin_lock(&stats->lock); if (stats->state == new_state) @@ -848,6 +851,9 @@ static ssize_t total_trans_show(struct device *dev, struct cooling_dev_stats *stats = cdev->stats; int ret; + if (!stats) + return -ENODEV; + spin_lock(&stats->lock); ret = sprintf(buf, "%u\n", stats->total_trans); spin_unlock(&stats->lock); @@ -864,6 +870,9 @@ time_in_state_ms_show(struct device *dev, struct device_attribute *attr, ssize_t len = 0; int i; + if (!stats) + return -ENODEV; + spin_lock(&stats->lock); update_time_in_state(stats); @@ -882,8 +891,12 @@ reset_store(struct device *dev, struct device_attribute *attr, const char *buf, { struct thermal_cooling_device *cdev = to_cooling_device(dev); struct cooling_dev_stats *stats = cdev->stats; - int i, states = stats->max_states; + int i, states; + + if (!stats) + return -ENODEV; + states = stats->max_states; spin_lock(&stats->lock); stats->total_trans = 0; @@ -907,6 +920,9 @@ static ssize_t trans_table_show(struct device *dev, ssize_t len = 0; int i, j; + if (!stats) + return -ENODEV; + len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n"); len += snprintf(buf + len, PAGE_SIZE - len, " : "); for (i = 0; i < stats->max_states; i++) {
There is a possible chance that some cooling device stats buffer allocation fails due to very high cooling device max state value. Later cooling device update or cooling stats sysfs will try to access stats data for the same cooling device. It will lead to NULL pointer dereference issue. Add a NULL pointer check before accessing thermal cooling device stats data. It fixes the following bug [ 26.812833] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000004 [ 27.122960] Call trace: [ 27.122963] do_raw_spin_lock+0x18/0xe8 [ 27.122966] _raw_spin_lock+0x24/0x30 [ 27.128157] thermal_cooling_device_stats_update+0x24/0x98 [ 27.128162] cur_state_store+0x88/0xb8 [ 27.128166] dev_attr_store+0x40/0x58 [ 27.128169] sysfs_kf_write+0x50/0x68 [ 27.133358] kernfs_fop_write+0x12c/0x1c8 [ 27.133362] __vfs_write+0x54/0x160 [ 27.152297] vfs_write+0xcc/0x188 [ 27.157132] ksys_write+0x78/0x108 [ 27.162050] ksys_write+0xf8/0x108 [ 27.166968] __arm_smccc_hvc+0x158/0x4b0 [ 27.166973] __arm_smccc_hvc+0x9c/0x4b0 [ 27.186005] el0_svc+0x8/0xc Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org> --- drivers/thermal/thermal_sysfs.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)