diff options
| author | Wang Cheng <wanngchenng@gmail.com> | 2022-05-19 14:08:54 -0700 |
|---|---|---|
| committer | akpm <akpm@linux-foundation.org> | 2022-05-19 14:08:54 -0700 |
| commit | 018160ad314d75b1409129b2247b614a9f35894c (patch) | |
| tree | 7e6d990a699acaa80ddb743f3b708508663b9f57 /mm/mempolicy.c | |
| parent | 6d4675e601357834dadd2ba1d803f6484596015c (diff) | |
mm/mempolicy: fix uninit-value in mpol_rebind_policy()
mpol_set_nodemask()(mm/mempolicy.c) does not set up nodemask when
pol->mode is MPOL_LOCAL. Check pol->mode before access
pol->w.cpuset_mems_allowed in mpol_rebind_policy()(mm/mempolicy.c).
BUG: KMSAN: uninit-value in mpol_rebind_policy mm/mempolicy.c:352 [inline]
BUG: KMSAN: uninit-value in mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368
mpol_rebind_policy mm/mempolicy.c:352 [inline]
mpol_rebind_task+0x2ac/0x2c0 mm/mempolicy.c:368
cpuset_change_task_nodemask kernel/cgroup/cpuset.c:1711 [inline]
cpuset_attach+0x787/0x15e0 kernel/cgroup/cpuset.c:2278
cgroup_migrate_execute+0x1023/0x1d20 kernel/cgroup/cgroup.c:2515
cgroup_migrate kernel/cgroup/cgroup.c:2771 [inline]
cgroup_attach_task+0x540/0x8b0 kernel/cgroup/cgroup.c:2804
__cgroup1_procs_write+0x5cc/0x7a0 kernel/cgroup/cgroup-v1.c:520
cgroup1_tasks_write+0x94/0xb0 kernel/cgroup/cgroup-v1.c:539
cgroup_file_write+0x4c2/0x9e0 kernel/cgroup/cgroup.c:3852
kernfs_fop_write_iter+0x66a/0x9f0 fs/kernfs/file.c:296
call_write_iter include/linux/fs.h:2162 [inline]
new_sync_write fs/read_write.c:503 [inline]
vfs_write+0x1318/0x2030 fs/read_write.c:590
ksys_write+0x28b/0x510 fs/read_write.c:643
__do_sys_write fs/read_write.c:655 [inline]
__se_sys_write fs/read_write.c:652 [inline]
__x64_sys_write+0xdb/0x120 fs/read_write.c:652
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
Uninit was created at:
slab_post_alloc_hook mm/slab.h:524 [inline]
slab_alloc_node mm/slub.c:3251 [inline]
slab_alloc mm/slub.c:3259 [inline]
kmem_cache_alloc+0x902/0x11c0 mm/slub.c:3264
mpol_new mm/mempolicy.c:293 [inline]
do_set_mempolicy+0x421/0xb70 mm/mempolicy.c:853
kernel_set_mempolicy mm/mempolicy.c:1504 [inline]
__do_sys_set_mempolicy mm/mempolicy.c:1510 [inline]
__se_sys_set_mempolicy+0x44c/0xb60 mm/mempolicy.c:1507
__x64_sys_set_mempolicy+0xd8/0x110 mm/mempolicy.c:1507
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x54/0xd0 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x44/0xae
KMSAN: uninit-value in mpol_rebind_task (2)
https://syzkaller.appspot.com/bug?id=d6eb90f952c2a5de9ea718a1b873c55cb13b59dc
This patch seems to fix below bug too.
KMSAN: uninit-value in mpol_rebind_mm (2)
https://syzkaller.appspot.com/bug?id=f2fecd0d7013f54ec4162f60743a2b28df40926b
The uninit-value is pol->w.cpuset_mems_allowed in mpol_rebind_policy().
When syzkaller reproducer runs to the beginning of mpol_new(),
mpol_new() mm/mempolicy.c
do_mbind() mm/mempolicy.c
kernel_mbind() mm/mempolicy.c
`mode` is 1(MPOL_PREFERRED), nodes_empty(*nodes) is `true` and `flags`
is 0. Then
mode = MPOL_LOCAL;
...
policy->mode = mode;
policy->flags = flags;
will be executed. So in mpol_set_nodemask(),
mpol_set_nodemask() mm/mempolicy.c
do_mbind()
kernel_mbind()
pol->mode is 4 (MPOL_LOCAL), that `nodemask` in `pol` is not initialized,
which will be accessed in mpol_rebind_policy().
Link: https://lkml.kernel.org/r/20220512123428.fq3wofedp6oiotd4@ppc.localdomain
Signed-off-by: Wang Cheng <wanngchenng@gmail.com>
Reported-by: <syzbot+217f792c92599518a2ab@syzkaller.appspotmail.com>
Tested-by: <syzbot+217f792c92599518a2ab@syzkaller.appspotmail.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/mempolicy.c')
| -rw-r--r-- | mm/mempolicy.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ed055e34d20c..d39b01fd52fe 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -351,7 +351,7 @@ static void mpol_rebind_preferred(struct mempolicy *pol, */ static void mpol_rebind_policy(struct mempolicy *pol, const nodemask_t *newmask) { - if (!pol) + if (!pol || pol->mode == MPOL_LOCAL) return; if (!mpol_store_user_nodemask(pol) && nodes_equal(pol->w.cpuset_mems_allowed, *newmask)) |