6.9-stable review patch. If anyone has any objections, please let me know.
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From: Heiko Carstens hca@linux.ibm.com
[ Upstream commit 87eceb17a987802aeee718be4decd19b56fc8e33 ]
When walking user stack frames the first stack frame (where the stack pointer points to) should be skipped: the return address of the current function is saved in the previous stack frame, not the current stack frame, which is allocated for to be called functions.
Fixes: aa44433ac4ee ("s390: add USER_STACKTRACE support") Reviewed-by: Jens Remus jremus@linux.ibm.com Signed-off-by: Heiko Carstens hca@linux.ibm.com Signed-off-by: Alexander Gordeev agordeev@linux.ibm.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/s390/kernel/stacktrace.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c index e580d4cd2729a..1c9e3b7739a22 100644 --- a/arch/s390/kernel/stacktrace.c +++ b/arch/s390/kernel/stacktrace.c @@ -95,6 +95,10 @@ void arch_stack_walk_user_common(stack_trace_consume_fn consume_entry, void *coo while (1) { if (__get_user(sp, &sf->back_chain)) break; + /* Sanity check: ABI requires SP to be 8 byte aligned. */ + if (!sp || sp & 0x7) + break; + sf = (void __user *)sp; if (__get_user(ip, &sf->gprs[8])) break; if (ip & 0x1) { @@ -110,10 +114,6 @@ void arch_stack_walk_user_common(stack_trace_consume_fn consume_entry, void *coo } if (!store_ip(consume_entry, cookie, entry, perf, ip)) return; - /* Sanity check: ABI requires SP to be aligned 8 bytes. */ - if (!sp || sp & 0x7) - break; - sf = (void __user *)sp; first = false; } pagefault_enable();