(second try, sending with mailx...)
After 3 days of successfully running 5.4.143 with this patch attached
and no issues, on a production workload (host + vms) of a busy
webserver and mysql database, I request queueing this for a future 5.4
stable, like the 5.10 one requested by Borislav; copying his mail text
in the hope that this is best form.
please queue for 5.4 stable
See https://bugzilla.kernel.org/show_bug.cgi?id=214159 for more info.
---
Commit 3a7956e25e1d7b3c148569e78895e1f3178122a9 upstream.
The kthread_is_per_cpu() construct relies on only being called on
PF_KTHREAD tasks (per the WARN in to_kthread). This gives rise to the
following usage pattern:
if ((p->flags & PF_KTHREAD) && kthread_is_per_cpu(p))
However, as reported by syzcaller, this is broken. The scenario is:
CPU0 CPU1 (running p)
(p->flags & PF_KTHREAD) // true
begin_new_exec()
me->flags &= ~(PF_KTHREAD|...);
kthread_is_per_cpu(p)
to_kthread(p)
WARN(!(p->flags & PF_KTHREAD) <-- *SPLAT*
Introduce __to_kthread() that omits the WARN and is sure to check both
values.
Use this to remove the problematic pattern for kthread_is_per_cpu()
and fix a number of other kthread_*() functions that have similar
issues but are currently not used in ways that would expose the
problem.
Notably kthread_func() is only ever called on 'current', while
kthread_probe_data() is only used for PF_WQ_WORKER, which implies the
task is from kthread_create*().
Fixes: ac687e6e8c26 ("kthread: Extract KTHREAD_IS_PER_CPU")
Signed-off-by: Peter Zijlstra (Intel) <peterz(a)infradead.org>
Signed-off-by: Patrick Schaaf <bof(a)bof.de>
diff --git a/kernel/kthread.c b/kernel/kthread.c
index b2bac5d929d2..22750a8af83e 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -76,6 +76,25 @@ static inline struct kthread *to_kthread(struct task_struct *k)
return (__force void *)k->set_child_tid;
}
+/*
+ * Variant of to_kthread() that doesn't assume @p is a kthread.
+ *
+ * Per construction; when:
+ *
+ * (p->flags & PF_KTHREAD) && p->set_child_tid
+ *
+ * the task is both a kthread and struct kthread is persistent. However
+ * PF_KTHREAD on it's own is not, kernel_thread() can exec() (See umh.c and
+ * begin_new_exec()).
+ */
+static inline struct kthread *__to_kthread(struct task_struct *p)
+{
+ void *kthread = (__force void *)p->set_child_tid;
+ if (kthread && !(p->flags & PF_KTHREAD))
+ kthread = NULL;
+ return kthread;
+}
+
void free_kthread_struct(struct task_struct *k)
{
struct kthread *kthread;
@@ -176,10 +195,11 @@ void *kthread_data(struct task_struct *task)
*/
void *kthread_probe_data(struct task_struct *task)
{
- struct kthread *kthread = to_kthread(task);
+ struct kthread *kthread = __to_kthread(task);
void *data = NULL;
- probe_kernel_read(&data, &kthread->data, sizeof(data));
+ if (kthread)
+ probe_kernel_read(&data, &kthread->data, sizeof(data));
return data;
}
@@ -490,9 +510,9 @@ void kthread_set_per_cpu(struct task_struct *k, int cpu)
set_bit(KTHREAD_IS_PER_CPU, &kthread->flags);
}
-bool kthread_is_per_cpu(struct task_struct *k)
+bool kthread_is_per_cpu(struct task_struct *p)
{
- struct kthread *kthread = to_kthread(k);
+ struct kthread *kthread = __to_kthread(p);
if (!kthread)
return false;
@@ -1272,11 +1292,9 @@ EXPORT_SYMBOL(kthread_destroy_worker);
*/
void kthread_associate_blkcg(struct cgroup_subsys_state *css)
{
- struct kthread *kthread;
+ struct kthread *kthread = __to_kthread(current);
+
- if (!(current->flags & PF_KTHREAD))
- return;
- kthread = to_kthread(current);
if (!kthread)
return;
@@ -1298,13 +1316,10 @@ EXPORT_SYMBOL(kthread_associate_blkcg);
*/
struct cgroup_subsys_state *kthread_blkcg(void)
{
- struct kthread *kthread;
+ struct kthread *kthread = __to_kthread(current);
- if (current->flags & PF_KTHREAD) {
- kthread = to_kthread(current);
- if (kthread)
- return kthread->blkcg_css;
- }
+ if (kthread)
+ return kthread->blkcg_css;
return NULL;
}
EXPORT_SYMBOL(kthread_blkcg);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 74cb20f32f72..87d9fad9d01d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7301,7 +7301,7 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
return 0;
/* Disregard pcpu kthreads; they are where they need to be. */
- if ((p->flags & PF_KTHREAD) && kthread_is_per_cpu(p))
+ if (kthread_is_per_cpu(p))
return 0;
if (!cpumask_test_cpu(env->dst_cpu, p->cpus_ptr)) {
[ Upstream commit a49145acfb975d921464b84fe00279f99827d816 ]
A fb_ioctl() FBIOPUT_VSCREENINFO call with invalid xres setting
or yres setting in struct fb_var_screeninfo will result in a
KASAN: vmalloc-out-of-bounds failure in bitfill_aligned() as
the margins are being cleared. The margins are cleared in
chunks and if the xres setting or yres setting is a value of
zero upto the chunk size, the failure will occur.
Add a margin check to validate xres and yres settings.
Note that, this patch needs special handling to backport it to linux
kernel 4.19, 4.14, 4.9, 4.4.
Signed-off-by: George Kennedy <george.kennedy(a)oracle.com>
Reported-by: syzbot+e5fd3e65515b48c02a30(a)syzkaller.appspotmail.com
Reviewed-by: Dan Carpenter <dan.carpenter(a)oracle.com>
Cc: Dhaval Giani <dhaval.giani(a)oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie(a)samsung.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1594149963-13801-1-git-send-e…
Signed-off-by: Sasha Levin <sashal(a)kernel.org>
---
drivers/video/fbdev/core/fbmem.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index 84845275dbef..de04c097d67c 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -991,6 +991,10 @@ fb_set_var(struct fb_info *info, struct fb_var_screeninfo *var)
goto done;
}
+ /* bitfill_aligned() assumes that it's at least 8x8 */
+ if (var->xres < 8 || var->yres < 8)
+ return -EINVAL;
+
ret = info->fbops->fb_check_var(var, info);
if (ret)
--
2.25.1
of_parse_thermal_zones() parses the thermal-zones node and registers a
thermal_zone device for each subnode. However, if a thermal zone is
consuming a thermal sensor and that thermal sensor device hasn't probed
yet, an attempt to set trip_point_*_temp for that thermal zone device
can cause a NULL pointer dereference. Fix it.
console:/sys/class/thermal/thermal_zone87 # echo 120000 > trip_point_0_temp
...
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020
...
Call trace:
of_thermal_set_trip_temp+0x40/0xc4
trip_point_temp_store+0xc0/0x1dc
dev_attr_store+0x38/0x88
sysfs_kf_write+0x64/0xc0
kernfs_fop_write_iter+0x108/0x1d0
vfs_write+0x2f4/0x368
ksys_write+0x7c/0xec
__arm64_sys_write+0x20/0x30
el0_svc_common.llvm.7279915941325364641+0xbc/0x1bc
do_el0_svc+0x28/0xa0
el0_svc+0x14/0x24
el0_sync_handler+0x88/0xec
el0_sync+0x1c0/0x200
Cc: stable(a)vger.kernel.org
Suggested-by: David Collins <quic_collinsd(a)quicinc.com>
Signed-off-by: Subbaraman Narayanamurthy <quic_subbaram(a)quicinc.com>
---
drivers/thermal/thermal_of.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
index 6379f26..ba53252 100644
--- a/drivers/thermal/thermal_of.c
+++ b/drivers/thermal/thermal_of.c
@@ -301,7 +301,7 @@ static int of_thermal_set_trip_temp(struct thermal_zone_device *tz, int trip,
if (trip >= data->ntrips || trip < 0)
return -EDOM;
- if (data->ops->set_trip_temp) {
+ if (data->ops && data->ops->set_trip_temp) {
int ret;
ret = data->ops->set_trip_temp(data->sensor_data, trip, temp);
--
2.7.4