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| author | Gerald Schaefer <gerald.schaefer@de.ibm.com> | 2020-02-27 12:56:42 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2020-03-04 11:18:03 +0100 |
| commit | 582b4e55403e053d8a48ff687a05174da9cc3fb0 (patch) | |
| tree | bfccd6c8badecf95646b1a322428a52435a8e53a /arch/s390 | |
| parent | 98d54f81e36ba3bf92172791eba5ca5bd813989b (diff) | |
| download | linux-582b4e55403e053d8a48ff687a05174da9cc3fb0.tar.gz linux-582b4e55403e053d8a48ff687a05174da9cc3fb0.tar.bz2 linux-582b4e55403e053d8a48ff687a05174da9cc3fb0.zip | |
s390/mm: fix panic in gup_fast on large pud
On s390 there currently is no implementation of pud_write(). That was ok
as long as we had our own implementation of get_user_pages_fast() which
checked for pud protection by testing the bit directly w/o using
pud_write(). The other callers of pud_write() are not reachable on s390.
After commit 1a42010cdc26 ("s390/mm: convert to the generic
get_user_pages_fast code") we use the generic get_user_pages_fast(), which
does call pud_write() in pud_access_permitted() for FOLL_WRITE access on
a large pud. Without an s390 specific pud_write(), the generic version is
called, which contains a BUG() statement to remind us that we don't have a
proper implementation. This results in a kernel panic.
Fix this by providing an implementation of pud_write().
Cc: <stable@vger.kernel.org> # 5.2+
Fixes: 1a42010cdc26 ("s390/mm: convert to the generic get_user_pages_fast code")
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 137a3920ca36..6d7c3b7e9281 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -752,6 +752,12 @@ static inline int pmd_write(pmd_t pmd) return (pmd_val(pmd) & _SEGMENT_ENTRY_WRITE) != 0; } +#define pud_write pud_write +static inline int pud_write(pud_t pud) +{ + return (pud_val(pud) & _REGION3_ENTRY_WRITE) != 0; +} + static inline int pmd_dirty(pmd_t pmd) { return (pmd_val(pmd) & _SEGMENT_ENTRY_DIRTY) != 0; |