diff options
| author | Peter Zijlstra <[email protected]> | 2019-07-18 10:47:47 +0200 |
|---|---|---|
| committer | Thomas Gleixner <[email protected]> | 2019-07-18 16:47:24 +0200 |
| commit | cac9b9a4b08304f11daace03b8b48659355e44c1 (patch) | |
| tree | cee56fc360060307af45a702ba4120ed90f66f11 | |
| parent | 8e144797f1a67c52e386161863da4614a23ad913 (diff) | |
stacktrace: Force USER_DS for stack_trace_save_user()
When walking userspace stacks, USER_DS needs to be set, otherwise
access_ok() will not function as expected.
Reported-by: Vegard Nossum <[email protected]>
Reported-by: Eiichi Tsukata <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Vegard Nossum <[email protected]>
Reviewed-by: Joel Fernandes (Google) <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
| -rw-r--r-- | kernel/stacktrace.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/kernel/stacktrace.c b/kernel/stacktrace.c index e6a02b274b73..f5440abb7532 100644 --- a/kernel/stacktrace.c +++ b/kernel/stacktrace.c @@ -226,12 +226,17 @@ unsigned int stack_trace_save_user(unsigned long *store, unsigned int size) .store = store, .size = size, }; + mm_segment_t fs; /* Trace user stack if not a kernel thread */ if (current->flags & PF_KTHREAD) return 0; + fs = get_fs(); + set_fs(USER_DS); arch_stack_walk_user(consume_entry, &c, task_pt_regs(current)); + set_fs(fs); + return c.len; } #endif |