kernel: Initialize cpumask before parsing

KMSAN complains that new_value at cpumask_parse_user() from write_irq_affinity() from irq_affinity_proc_write() is uninitialized. [ 148.133411][ T5509] ===================================================== [ 148.135383][ T5509] BUG: KMSAN: uninit-value in find_next_bit+0x325/0x340 [ 148.137819][ T5509] [ 148.138448][ T5509] Local variable ----new_value.i@irq_affinity_proc_write created at: [ 148.140768][ T5509] irq_affinity_proc_write+0xc3/0x3d0 [ 148.142298][ T5509] irq_affinity_proc_write+0xc3/0x3d0 [ 148.143823][ T5509] ===================================================== Since bitmap_parse() from cpumask_parse_user() calls find_next_bit(), any alloc_cpumask_var() + cpumask_parse_user() sequence has possibility that find_next_bit() accesses uninitialized cpu mask variable. Fix this problem by replacing alloc_cpumask_var() with zalloc_cpumask_var(). Signed-off-by: Tetsuo Handa <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Acked-by: Steven Rostedt (VMware) <[email protected]> Link: https://lore.kernel.org/r/[email protected]
fracktal · Apr 10, 2021 · c5e3a41 · c5e3a41
1 parent 883ccef
commit c5e3a41
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Showing 3 changed files with 4 additions and 4 deletions.
diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
@@ -144,7 +144,7 @@ static ssize_t write_irq_affinity(int type, struct file *file,
 	if (!irq_can_set_affinity_usr(irq) || no_irq_affinity)
 		return -EIO;
 
-	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
+	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
 		return -ENOMEM;
 
 	if (type)
@@ -238,7 +238,7 @@ static ssize_t default_affinity_write(struct file *file,
 	cpumask_var_t new_value;
 	int err;
 
-	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
+	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
 		return -ENOMEM;
 
 	err = cpumask_parse_user(buffer, count, new_value);

diff --git a/kernel/profile.c b/kernel/profile.c
@@ -430,7 +430,7 @@ static ssize_t prof_cpu_mask_proc_write(struct file *file,
 	cpumask_var_t new_value;
 	int err;
 
-	if (!alloc_cpumask_var(&new_value, GFP_KERNEL))
+	if (!zalloc_cpumask_var(&new_value, GFP_KERNEL))
 		return -ENOMEM;
 
 	err = cpumask_parse_user(buffer, count, new_value);

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
@@ -4827,7 +4827,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
 	cpumask_var_t tracing_cpumask_new;
 	int err;
 
-	if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+	if (!zalloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
 		return -ENOMEM;
 
 	err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);