From: linyujun linyujun809@huawei.com
[ Upstream commit 9be4c88bb7924f68f88cfd47d925c2d046f51a73 ]
The following KASAN warning is detected by QEMU.
================================================================== BUG: KASAN: stack-out-of-bounds in unwind_frame+0x508/0x870 Read of size 4 at addr c36bba90 by task cat/163
CPU: 1 PID: 163 Comm: cat Not tainted 5.10.0-rc1 #40 Hardware name: ARM-Versatile Express [<c0113fac>] (unwind_backtrace) from [<c010e71c>] (show_stack+0x10/0x14) [<c010e71c>] (show_stack) from [<c0b805b4>] (dump_stack+0x98/0xb0) [<c0b805b4>] (dump_stack) from [<c0b7d658>] (print_address_description.constprop.0+0x58/0x4bc) [<c0b7d658>] (print_address_description.constprop.0) from [<c031435c>] (kasan_report+0x154/0x170) [<c031435c>] (kasan_report) from [<c0113c44>] (unwind_frame+0x508/0x870) [<c0113c44>] (unwind_frame) from [<c010e298>] (__save_stack_trace+0x110/0x134) [<c010e298>] (__save_stack_trace) from [<c01ce0d8>] (stack_trace_save+0x8c/0xb4) [<c01ce0d8>] (stack_trace_save) from [<c0313520>] (kasan_set_track+0x38/0x60) [<c0313520>] (kasan_set_track) from [<c0314cb8>] (kasan_set_free_info+0x20/0x2c) [<c0314cb8>] (kasan_set_free_info) from [<c0313474>] (__kasan_slab_free+0xec/0x120) [<c0313474>] (__kasan_slab_free) from [<c0311e20>] (kmem_cache_free+0x7c/0x334) [<c0311e20>] (kmem_cache_free) from [<c01c35dc>] (rcu_core+0x390/0xccc) [<c01c35dc>] (rcu_core) from [<c01013a8>] (__do_softirq+0x180/0x518) [<c01013a8>] (__do_softirq) from [<c0135214>] (irq_exit+0x9c/0xe0) [<c0135214>] (irq_exit) from [<c01a40e4>] (__handle_domain_irq+0xb0/0x110) [<c01a40e4>] (__handle_domain_irq) from [<c0691248>] (gic_handle_irq+0xa0/0xb8) [<c0691248>] (gic_handle_irq) from [<c0100b0c>] (__irq_svc+0x6c/0x94) Exception stack(0xc36bb928 to 0xc36bb970) b920: c36bb9c0 00000000 c0126919 c0101228 c36bb9c0 b76d7730 b940: c36b8000 c36bb9a0 c3335b00 c01ce0d8 00000003 c36bba3c c36bb940 c36bb978 b960: c010e298 c011373c 60000013 ffffffff [<c0100b0c>] (__irq_svc) from [<c011373c>] (unwind_frame+0x0/0x870) [<c011373c>] (unwind_frame) from [<00000000>] (0x0)
The buggy address belongs to the page: page:(ptrval) refcount:0 mapcount:0 mapping:00000000 index:0x0 pfn:0x636bb flags: 0x0() raw: 00000000 00000000 ef867764 00000000 00000000 00000000 ffffffff 00000000 page dumped because: kasan: bad access detected
addr c36bba90 is located in stack of task cat/163 at offset 48 in frame: stack_trace_save+0x0/0xb4
this frame has 1 object: [32, 48) 'trace'
Memory state around the buggy address: c36bb980: f1 f1 f1 f1 00 04 f2 f2 00 00 f3 f3 00 00 00 00 c36bba00: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
c36bba80: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
^ c36bbb00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 c36bbb80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ==================================================================
There is a same issue on x86 and has been resolved by the commit f7d27c35ddff ("x86/mm, kasan: Silence KASAN warnings in get_wchan()"). The solution could be applied to arm architecture too.
Signed-off-by: Lin Yujun linyujun809@huawei.com Reported-by: He Ying heying24@huawei.com Signed-off-by: Russell King (Oracle) rmk+kernel@armlinux.org.uk Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm/kernel/stacktrace.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c index c10c1de244eb..83d0aa217bb2 100644 --- a/arch/arm/kernel/stacktrace.c +++ b/arch/arm/kernel/stacktrace.c @@ -50,17 +50,17 @@ int notrace unwind_frame(struct stackframe *frame) return -EINVAL;
frame->sp = frame->fp; - frame->fp = *(unsigned long *)(fp); - frame->pc = *(unsigned long *)(fp + 4); + frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); + frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 4)); #else /* check current frame pointer is within bounds */ if (fp < low + 12 || fp > high - 4) return -EINVAL;
/* restore the registers from the stack frame */ - frame->fp = *(unsigned long *)(fp - 12); - frame->sp = *(unsigned long *)(fp - 8); - frame->pc = *(unsigned long *)(fp - 4); + frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 12)); + frame->sp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 8)); + frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 4)); #endif
return 0;