summaryrefslogtreecommitdiff
path: root/fs
diff options
context:
space:
mode:
authorGao Xiang <hsiangkao@linux.alibaba.com>2022-09-02 07:57:10 +0300
committerGao Xiang <hsiangkao@linux.alibaba.com>2022-09-05 18:23:30 +0300
commit2f44013e39984c127c6efedf70e6b5f4e9dcf315 (patch)
treea15f1e493d242b82f2c6662da50d02e86d46c8fd /fs
parentea0b7b0d59e81a9c1bc03f8696bb04851bc2ad22 (diff)
downloadlinux-2f44013e39984c127c6efedf70e6b5f4e9dcf315.tar.xz
erofs: fix pcluster use-after-free on UP platforms
During stress testing with CONFIG_SMP disabled, KASAN reports as below: ================================================================== BUG: KASAN: use-after-free in __mutex_lock+0xe5/0xc30 Read of size 8 at addr ffff8881094223f8 by task stress/7789 CPU: 0 PID: 7789 Comm: stress Not tainted 6.0.0-rc1-00002-g0d53d2e882f9 #3 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 Call Trace: <TASK> .. __mutex_lock+0xe5/0xc30 .. z_erofs_do_read_page+0x8ce/0x1560 .. z_erofs_readahead+0x31c/0x580 .. Freed by task 7787 kasan_save_stack+0x1e/0x40 kasan_set_track+0x20/0x30 kasan_set_free_info+0x20/0x40 __kasan_slab_free+0x10c/0x190 kmem_cache_free+0xed/0x380 rcu_core+0x3d5/0xc90 __do_softirq+0x12d/0x389 Last potentially related work creation: kasan_save_stack+0x1e/0x40 __kasan_record_aux_stack+0x97/0xb0 call_rcu+0x3d/0x3f0 erofs_shrink_workstation+0x11f/0x210 erofs_shrink_scan+0xdc/0x170 shrink_slab.constprop.0+0x296/0x530 drop_slab+0x1c/0x70 drop_caches_sysctl_handler+0x70/0x80 proc_sys_call_handler+0x20a/0x2f0 vfs_write+0x555/0x6c0 ksys_write+0xbe/0x160 do_syscall_64+0x3b/0x90 The root cause is that erofs_workgroup_unfreeze() doesn't reset to orig_val thus it causes a race that the pcluster reuses unexpectedly before freeing. Since UP platforms are quite rare now, such path becomes unnecessary. Let's drop such specific-designed path directly instead. Fixes: 73f5c66df3e2 ("staging: erofs: fix `erofs_workgroup_{try_to_freeze, unfreeze}'") Reviewed-by: Yue Hu <huyue2@coolpad.com> Reviewed-by: Chao Yu <chao@kernel.org> Link: https://lore.kernel.org/r/20220902045710.109530-1-hsiangkao@linux.alibaba.com Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/erofs/internal.h29
1 files changed, 0 insertions, 29 deletions
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index cfee49d33b95..a01cc82795a2 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -195,7 +195,6 @@ struct erofs_workgroup {
atomic_t refcount;
};
-#if defined(CONFIG_SMP)
static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
int val)
{
@@ -224,34 +223,6 @@ static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
return atomic_cond_read_relaxed(&grp->refcount,
VAL != EROFS_LOCKED_MAGIC);
}
-#else
-static inline bool erofs_workgroup_try_to_freeze(struct erofs_workgroup *grp,
- int val)
-{
- preempt_disable();
- /* no need to spin on UP platforms, let's just disable preemption. */
- if (val != atomic_read(&grp->refcount)) {
- preempt_enable();
- return false;
- }
- return true;
-}
-
-static inline void erofs_workgroup_unfreeze(struct erofs_workgroup *grp,
- int orig_val)
-{
- preempt_enable();
-}
-
-static inline int erofs_wait_on_workgroup_freezed(struct erofs_workgroup *grp)
-{
- int v = atomic_read(&grp->refcount);
-
- /* workgroup is never freezed on uniprocessor systems */
- DBG_BUGON(v == EROFS_LOCKED_MAGIC);
- return v;
-}
-#endif /* !CONFIG_SMP */
#endif /* !CONFIG_EROFS_FS_ZIP */
/* we strictly follow PAGE_SIZE and no buffer head yet */