From 5f9a54b11ba198a60a195dc6538db7309f0d5076 Mon Sep 17 00:00:00 2001 From: Tetsuo Handa Date: Thu, 1 Apr 2021 14:58:23 +0900 Subject: [PATCH] kernel: Initialize cpumask before parsing [ Upstream commit c5e3a41187ac01425f5ad1abce927905e4ac44e4 ] 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 Signed-off-by: Thomas Gleixner Acked-by: Steven Rostedt (VMware) Link: https://lore.kernel.org/r/20210401055823.3929-1-penguin-kernel@I-love.SAKURA.ne.jp Stable-dep-of: 98feccbf32cf ("tracing: Prevent bad count for tracing_cpumask_write") Signed-off-by: Sasha Levin --- kernel/irq/proc.c | 4 ++-- kernel/profile.c | 2 +- kernel/trace/trace.c | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c index 1a322800b..26c035c4c 100755 --- a/kernel/irq/proc.c +++ b/kernel/irq/proc.c @@ -145,7 +145,7 @@ 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) @@ -239,7 +239,7 @@ 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 index 737b1c704..0db112285 100755 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -438,7 +438,7 @@ 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 index b00682e0f..1503cd622 100755 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4831,7 +4831,7 @@ 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);