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| author | Eiichi Tsukata <devel@etsukata.com> | 2019-07-22 10:32:16 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2019-07-22 10:42:36 +0200 |
| commit | 2af7c85714d8cafadf925d55441458eae312cd6b (patch) | |
| tree | 0b01c1b3b8826d4c192bf401ba01070080e054a5 | |
| parent | mm/vmalloc: Sync unmappings in __purge_vmap_area_lazy() (diff) | |
| download | linux-2af7c85714d8cafadf925d55441458eae312cd6b.tar.xz linux-2af7c85714d8cafadf925d55441458eae312cd6b.zip | |
x86/stacktrace: Prevent access_ok() warnings in arch_stack_walk_user()
When arch_stack_walk_user() is called from atomic contexts, access_ok() can
trigger the following warning if compiled with CONFIG_DEBUG_ATOMIC_SLEEP=y.
Reproducer:
// CONFIG_DEBUG_ATOMIC_SLEEP=y
# cd /sys/kernel/debug/tracing
# echo 1 > options/userstacktrace
# echo 1 > events/irq/irq_handler_entry/enable
WARNING: CPU: 0 PID: 2649 at arch/x86/kernel/stacktrace.c:103 arch_stack_walk_user+0x6e/0xf6
CPU: 0 PID: 2649 Comm: bash Not tainted 5.3.0-rc1+ #99
RIP: 0010:arch_stack_walk_user+0x6e/0xf6
Call Trace:
<IRQ>
stack_trace_save_user+0x10a/0x16d
trace_buffer_unlock_commit_regs+0x185/0x240
trace_event_buffer_commit+0xec/0x330
trace_event_raw_event_irq_handler_entry+0x159/0x1e0
__handle_irq_event_percpu+0x22d/0x440
handle_irq_event_percpu+0x70/0x100
handle_irq_event+0x5a/0x8b
handle_edge_irq+0x12f/0x3f0
handle_irq+0x34/0x40
do_IRQ+0xa6/0x1f0
common_interrupt+0xf/0xf
</IRQ>
Fix it by calling __range_not_ok() directly instead of access_ok() as
copy_from_user_nmi() does. This is fine here because the actual copy is
inside a pagefault disabled region.
Reported-by: Juri Lelli <juri.lelli@gmail.com>
Signed-off-by: Eiichi Tsukata <devel@etsukata.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190722083216.16192-2-devel@etsukata.com
| -rw-r--r-- | arch/x86/kernel/stacktrace.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c index 4f36d3241faf..2d6898c2cb64 100644 --- a/arch/x86/kernel/stacktrace.c +++ b/arch/x86/kernel/stacktrace.c @@ -100,7 +100,7 @@ copy_stack_frame(const void __user *fp, struct stack_frame_user *frame) { int ret; - if (!access_ok(fp, sizeof(*frame))) + if (__range_not_ok(fp, sizeof(*frame), TASK_SIZE)) return 0; ret = 1; |