diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2019-07-18 11:47:47 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-18 17:47:24 +0300 |
| commit | cac9b9a4b08304f11daace03b8b48659355e44c1 (patch) | |
| tree | cee56fc360060307af45a702ba4120ed90f66f11 | |
| parent | 8e144797f1a67c52e386161863da4614a23ad913 (diff) | |
| download | linux-cac9b9a4b08304f11daace03b8b48659355e44c1.tar.xz | |
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 <vegard.nossum@oracle.com>
Reported-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Link: https://lkml.kernel.org/r/20190718085754.GM3402@hirez.programming.kicks-ass.net
| -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 |