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Fixes for 5.5-rc1: 

- Fix a UAF when reporting writeback errors
 - Fix a race condition when handling page uptodate on a blocksize <
   pagesize file that is also fragmented
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Merge tag 'iomap-5.5-merge-14' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull iomap fixes from Darrick Wong:
 "Fix a race condition and a use-after-free error:

   - Fix a UAF when reporting writeback errors

   - Fix a race condition when handling page uptodate on fragmented file
     with blocksize < pagesize"

* tag 'iomap-5.5-merge-14' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  iomap: stop using ioend after it's been freed in iomap_finish_ioend()
  iomap: fix sub-page uptodate handling
This commit is contained in:
Linus Torvalds 2019-12-07 17:07:18 -08:00
parent 50caca9d7f c275779ff2
commit 95207d554b
1 changed files with 28 additions and 12 deletions
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40
fs/iomap/buffered-io.c
View File

@ -28,6 +28,7 @@
struct iomap_page {
atomic_t read_count;
atomic_t write_count;
spinlock_t uptodate_lock;
DECLARE_BITMAP(uptodate, PAGE_SIZE / 512);
};
@ -51,6 +52,7 @@ iomap_page_create(struct inode *inode, struct page *page)
iop = kmalloc(sizeof(*iop), GFP_NOFS | __GFP_NOFAIL);
atomic_set(&iop->read_count, 0);
atomic_set(&iop->write_count, 0);
spin_lock_init(&iop->uptodate_lock);
bitmap_zero(iop->uptodate, PAGE_SIZE / SECTOR_SIZE);
/*
@ -139,25 +141,38 @@ iomap_adjust_read_range(struct inode *inode, struct iomap_page *iop,
}
static void
iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
iomap_iop_set_range_uptodate(struct page *page, unsigned off, unsigned len)
{
struct iomap_page *iop = to_iomap_page(page);
struct inode *inode = page->mapping->host;
unsigned first = off >> inode->i_blkbits;
unsigned last = (off + len - 1) >> inode->i_blkbits;
unsigned int i;
bool uptodate = true;
unsigned long flags;
unsigned int i;
if (iop) {
for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
if (i >= first && i <= last)
set_bit(i, iop->uptodate);
else if (!test_bit(i, iop->uptodate))
uptodate = false;
}
spin_lock_irqsave(&iop->uptodate_lock, flags);
for (i = 0; i < PAGE_SIZE / i_blocksize(inode); i++) {
if (i >= first && i <= last)
set_bit(i, iop->uptodate);
else if (!test_bit(i, iop->uptodate))
uptodate = false;
}
if (uptodate && !PageError(page))
if (uptodate)
SetPageUptodate(page);
spin_unlock_irqrestore(&iop->uptodate_lock, flags);
}
static void
iomap_set_range_uptodate(struct page *page, unsigned off, unsigned len)
{
if (PageError(page))
return;
if (page_has_private(page))
iomap_iop_set_range_uptodate(page, off, len);
else
SetPageUptodate(page);
}
@ -1128,6 +1143,7 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error)
struct bio *bio = &ioend->io_inline_bio;
struct bio *last = ioend->io_bio, *next;
u64 start = bio->bi_iter.bi_sector;
loff_t offset = ioend->io_offset;
bool quiet = bio_flagged(bio, BIO_QUIET);
for (bio = &ioend->io_inline_bio; bio; bio = next) {
@ -1148,12 +1164,12 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error)
iomap_finish_page_writeback(inode, bv->bv_page, error);
bio_put(bio);
}
/* The ioend has been freed by bio_put() */
if (unlikely(error && !quiet)) {
printk_ratelimited(KERN_ERR
"%s: writeback error on inode %lu, offset %lld, sector %llu",
inode->i_sb->s_id, inode->i_ino, ioend->io_offset,
start);
inode->i_sb->s_id, inode->i_ino, offset, start);
}
}