linux/arch
Vasily Gorbik b4adfe5591 s390/ftrace: save traced function caller
A typical backtrace acquired from ftraced function currently looks like
the following (e.g. for "path_openat"):

arch_stack_walk+0x15c/0x2d8
stack_trace_save+0x50/0x68
stack_trace_call+0x15a/0x3b8
ftrace_graph_caller+0x0/0x1c
0x3e0007e3c98 <- ftraced function caller (should be do_filp_open+0x7c/0xe8)
do_open_execat+0x70/0x1b8
__do_execve_file.isra.0+0x7d8/0x860
__s390x_sys_execve+0x56/0x68
system_call+0xdc/0x2d8

Note random "0x3e0007e3c98" stack value as ftraced function caller. This
value causes either imprecise unwinder result or unwinding failure.
That "0x3e0007e3c98" comes from r14 of ftraced function stack frame, which
it haven't had a chance to initialize since the very first instruction
calls ftrace code ("ftrace_caller"). (ftraced function might never
save r14 as well). Nevertheless according to s390 ABI any function
is called with stack frame allocated for it and r14 contains return
address. "ftrace_caller" itself is called with "brasl %r0,ftrace_caller".
So, to fix this issue simply always save traced function caller onto
ftraced function stack frame.

Reported-by: Sven Schnelle <svens@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
2019-12-18 23:29:26 +01:00
..
alpha alpha: use pgtable-nopud instead of 4level-fixup 2019-12-04 19:44:14 -08:00
arc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
arm Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 2019-12-14 12:32:28 -08:00
arm64 ARM: SoC fixes 2019-12-06 14:19:37 -08:00
c6x c6x: use pgtable-nopud instead of 4level-fixup 2019-12-04 19:44:15 -08:00
csky dma-mapping updates for 5.5-rc1 2019-11-28 11:16:43 -08:00
h8300 h8300: Move EXCEPTION_TABLE to RO_DATA segment 2019-11-04 18:12:55 +01:00
hexagon Kbuild updates for v5.5 2019-12-02 17:35:04 -08:00
ia64 drm msm + fixes for 5.5-rc1 2019-12-06 10:28:09 -08:00
m68k Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu 2019-12-05 12:20:42 -08:00
microblaze microblaze: use pgtable-nopmd instead of 4level-fixup 2019-12-04 19:44:15 -08:00
mips MIPS: OCTEON: Replace SIZEOF_FIELD() macro 2019-12-09 10:33:50 -08:00
nds32 nds32: use pgtable-nopmd instead of 4level-fixup 2019-12-04 19:44:15 -08:00
nios2 nios2: Fix ioremap 2019-12-12 16:34:33 +08:00
openrisc OpenRISC updates for 5.5 2019-12-02 17:18:43 -08:00
parisc parisc/hugetlb: use pgtable-nopXd instead of 4level-fixup 2019-12-04 19:44:15 -08:00
powerpc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
riscv riscv: only select serial sifive if TTY is enabled 2019-12-08 20:29:01 -08:00
s390 s390/ftrace: save traced function caller 2019-12-18 23:29:26 +01:00
sh Wimplicit-fallthrough patches for 5.5-rc2 2019-12-14 16:10:22 -08:00
sparc treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
um um: add support for folded p4d page tables 2019-12-04 19:44:15 -08:00
unicore32 generic ioremap support 2019-11-28 10:57:12 -08:00
x86 treewide conversion from FIELD_SIZEOF() to sizeof_field() 2019-12-13 14:02:12 -08:00
xtensa arch: sembuf.h: make uapi asm/sembuf.h self-contained 2019-12-04 19:44:14 -08:00
.gitignore
Kconfig arch/Kconfig: fix indentation 2019-12-04 19:44:12 -08:00