diff options
| author | Junxiao Bi <junxiao.bi@oracle.com> | 2012-08-22 10:21:07 +0800 |
|---|---|---|
| committer | Willy Tarreau <w@1wt.eu> | 2012-10-07 23:37:14 +0200 |
| commit | 2f42878e56a734563c5e2aadee6e334477500cdf (patch) | |
| tree | 044b671587aaf7bef24e41acf1e8818bf610b545 /arch | |
| parent | 012660d6b30072633c89033d2b3e18a9a861ae3d (diff) | |
oprofile: use KM_NMI slot for kmap_atomic
If one kernel path is using KM_USER0 slot and is interrupted by
the oprofile nmi, then in copy_from_user_nmi(), the KM_USER0 slot
will be overwrite and cleared to zero at last, when the control
return to the original kernel path, it will access an invalid
virtual address and trigger a crash.
Cc: Robert Richter <robert.richter@amd.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com>
[WT: According to Junxiao and Robert, this patch is needed for stable kernels
which include a backport of a0e3e70243f5b270bc3eca718f0a9fa5e6b8262e without
3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73, but there is no exact equivalent in
mainline]
Signed-off-by: Willy Tarreau <w@1wt.eu>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/oprofile/backtrace.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/oprofile/backtrace.c b/arch/x86/oprofile/backtrace.c index 829edf0642c4..b50a2802e31f 100644 --- a/arch/x86/oprofile/backtrace.c +++ b/arch/x86/oprofile/backtrace.c @@ -71,9 +71,9 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) offset = addr & (PAGE_SIZE - 1); size = min(PAGE_SIZE - offset, n - len); - map = kmap_atomic(page, KM_USER0); + map = kmap_atomic(page, KM_NMI); memcpy(to, map+offset, size); - kunmap_atomic(map, KM_USER0); + kunmap_atomic(map, KM_NMI); put_page(page); len += size; |