diff options
| author | Li Zetao <lizetao1@huawei.com> | 2022-10-28 15:37:17 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-11-08 15:57:23 -0800 |
| commit | cc674ab3c0188002917c8a2c28e4424131f1fd7e (patch) | |
| tree | 240329a69b503fb19309a594851ad0f7748387ca | |
| parent | 8625147cafaa9ba74713d682f5185eb62cb2aedb (diff) | |
| download | linux-cc674ab3c0188002917c8a2c28e4424131f1fd7e.tar.bz2 | |
mm/mmap: fix memory leak in mmap_region()
There is a memory leak reported by kmemleak:
unreferenced object 0xffff88817231ce40 (size 224):
comm "mount.cifs", pid 19308, jiffies 4295917571 (age 405.880s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
60 c0 b2 00 81 88 ff ff 98 83 01 42 81 88 ff ff `..........B....
backtrace:
[<ffffffff81936171>] __alloc_file+0x21/0x250
[<ffffffff81937051>] alloc_empty_file+0x41/0xf0
[<ffffffff81937159>] alloc_file+0x59/0x710
[<ffffffff81937964>] alloc_file_pseudo+0x154/0x210
[<ffffffff81741dbf>] __shmem_file_setup+0xff/0x2a0
[<ffffffff817502cd>] shmem_zero_setup+0x8d/0x160
[<ffffffff817cc1d5>] mmap_region+0x1075/0x19d0
[<ffffffff817cd257>] do_mmap+0x727/0x1110
[<ffffffff817518b2>] vm_mmap_pgoff+0x112/0x1e0
[<ffffffff83adf955>] do_syscall_64+0x35/0x80
[<ffffffff83c0006a>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
The root cause was traced to an error handing path in mmap_region() when
arch_validate_flags() or mas_preallocate() fails. In the shared anonymous
mapping sence, vma will be setuped and mapped with a new shared anonymous
file via shmem_zero_setup(). So in this case, the file resource needs to
be released.
Fix it by calling fput(vma->vm_file) and unmap_region() when
arch_validate_flags() or mas_preallocate() returns an error in the shared
anonymous mapping sence.
Link: https://lkml.kernel.org/r/20221028073717.1179380-1-lizetao1@huawei.com
Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree")
Fixes: c462ac288f2c ("mm: Introduce arch_validate_flags()")
Signed-off-by: Li Zetao <lizetao1@huawei.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/mmap.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 2def55555e05..c3c5c1d6103d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2674,6 +2674,8 @@ cannot_expand: error = -EINVAL; if (file) goto close_and_free_vma; + else if (vma->vm_file) + goto unmap_and_free_vma; else goto free_vma; } @@ -2682,6 +2684,8 @@ cannot_expand: error = -ENOMEM; if (file) goto close_and_free_vma; + else if (vma->vm_file) + goto unmap_and_free_vma; else goto free_vma; } @@ -2751,7 +2755,7 @@ unmap_and_free_vma: /* Undo any partial mapping done by a device driver. */ unmap_region(mm, mas.tree, vma, prev, next, vma->vm_start, vma->vm_end); - if (vm_flags & VM_SHARED) + if (file && (vm_flags & VM_SHARED)) mapping_unmap_writable(file->f_mapping); free_vma: vm_area_free(vma); |