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| author | Vasily Gorbik <gor@linux.ibm.com> | 2018-09-14 18:29:39 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-11-20 20:47:08 +0300 |
| commit | 84bfa03445bc34bf486036c124890b6a3a7022af (patch) | |
| tree | fa97fa4a48a65ccafb8c087074f821a7b7326192 /arch/s390/include/asm | |
| parent | 3d510bdf35c23ca72cfbf40eb84c04e1cbd3a4d8 (diff) | |
| download | linux-84bfa03445bc34bf486036c124890b6a3a7022af.tar.xz | |
s390/vdso: avoid 64-bit vdso mapping for compat tasks
[ Upstream commit d1befa65823e9c6d013883b8a41d081ec338c489 ]
vdso_fault used is_compat_task function (on s390 it tests "current"
thread_info flags) to distinguish compat tasks and map 31-bit vdso
pages. But "current" task might not correspond to mm context.
When 31-bit compat inferior is executed under gdb, gdb does
PTRACE_PEEKTEXT on vdso page, causing vdso_fault with "current" being
64-bit gdb process. So, 31-bit inferior ends up with 64-bit vdso mapped.
To avoid this problem a new compat_mm flag has been introduced into
mm context. This flag is used in vdso_fault and vdso_mremap instead
of is_compat_task.
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch/s390/include/asm')
| -rw-r--r-- | arch/s390/include/asm/mmu.h | 2 | ||||
| -rw-r--r-- | arch/s390/include/asm/mmu_context.h | 1 |
2 files changed, 3 insertions, 0 deletions
diff --git a/arch/s390/include/asm/mmu.h b/arch/s390/include/asm/mmu.h index a8418e1379eb..bcfb6371086f 100644 --- a/arch/s390/include/asm/mmu.h +++ b/arch/s390/include/asm/mmu.h @@ -32,6 +32,8 @@ typedef struct { unsigned int uses_cmm:1; /* The gmaps associated with this context are allowed to use huge pages. */ unsigned int allow_gmap_hpage_1m:1; + /* The mmu context is for compat task */ + unsigned int compat_mm:1; } mm_context_t; #define INIT_MM_CONTEXT(name) \ diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h index 09b61d0e491f..e4462202200d 100644 --- a/arch/s390/include/asm/mmu_context.h +++ b/arch/s390/include/asm/mmu_context.h @@ -25,6 +25,7 @@ static inline int init_new_context(struct task_struct *tsk, atomic_set(&mm->context.flush_count, 0); mm->context.gmap_asce = 0; mm->context.flush_mm = 0; + mm->context.compat_mm = 0; #ifdef CONFIG_PGSTE mm->context.alloc_pgste = page_table_allocate_pgste || test_thread_flag(TIF_PGSTE) || |