| Message ID | 20221028073717.1179380-1-lizetao1@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] mm/mmap: Fix memory leak in mmap_region() | expand |
* Li Zetao <lizetao1@huawei.com> [221028 02:48]: > 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. > Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.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> > --- > v1 was posted at: https://lore.kernel.org/all/20221027025837.136492-1-lizetao1@huawei.com/ > v1 -> v2: Drop the new goto label, and jump to unmap_and_free_vma "if (vma->vm_file)" > > mm/mmap.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index e270057ed04e..77846d8cf9d4 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2674,6 +2674,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > 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 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > 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 @@ unsigned long mmap_region(struct file *file, unsigned long addr, > > /* 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); > -- > 2.25.1 >
diff --git a/mm/mmap.c b/mm/mmap.c index e270057ed04e..77846d8cf9d4 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2674,6 +2674,8 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 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 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 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 @@ unsigned long mmap_region(struct file *file, unsigned long addr, /* 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);
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. Fixes: d4af56c5c7c6 ("mm: start tracking VMAs with maple tree") Fixes: c462ac288f2c ("mm: Introduce arch_validate_flags()") Signed-off-by: Li Zetao <lizetao1@huawei.com> --- v1 was posted at: https://lore.kernel.org/all/20221027025837.136492-1-lizetao1@huawei.com/ v1 -> v2: Drop the new goto label, and jump to unmap_and_free_vma "if (vma->vm_file)" mm/mmap.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)