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author | Dave Young <dyoung@redhat.com> | 2016-03-17 14:21:03 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-03-17 15:09:34 -0700 |
commit | 0b50a2d86d8e9a6d58e2ca3e5657f962eb698d2f (patch) | |
tree | 3df4d5824d8abc91faf32f27a1f1293d041ac784 /arch/mn10300 | |
parent | 7e2bc81da333f0d4ca68882fdaef41e1b0d5690d (diff) | |
download | linux-0b50a2d86d8e9a6d58e2ca3e5657f962eb698d2f.tar.bz2 |
proc-vmcore: wrong data type casting fix
On i686 PAE enabled machine the contiguous physical area could be large
and it can cause trimming down variables in below calculation in
read_vmcore() and mmap_vmcore():
tsz = min_t(size_t, m->offset + m->size - *fpos, buflen);
That is, the types being used is like below on i686:
m->offset: unsigned long long int
m->size: unsigned long long int
*fpos: loff_t (long long int)
buflen: size_t (unsigned int)
So casting (m->offset + m->size - *fpos) by size_t means truncating a
given value by 4GB.
Suppose (m->offset + m->size - *fpos) being truncated to 0, buflen >0
then we will get tsz = 0. It is of course not an expected result.
Similarly we could also get other truncated values less than buflen.
Then the real size passed down is not correct any more.
If (m->offset + m->size - *fpos) is above 4GB, read_vmcore or
mmap_vmcore use the min_t result with truncated values being compared to
buflen. Then, fpos proceeds with the wrong value so that we reach below
bugs:
1) read_vmcore will refuse to continue so makedumpfile fails.
2) mmap_vmcore will trigger BUG_ON() in remap_pfn_range().
Use unsigned long long in min_t instead so that the variables in are not
truncated.
Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Dave Young <dyoung@redhat.com>
Cc: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jianyu Zhan <nasa4836@gmail.com>
Cc: Minfei Huang <mhuang@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/mn10300')
0 files changed, 0 insertions, 0 deletions