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| author | Vasily Gorbik <gor@linux.ibm.com> | 2022-03-05 13:16:07 +0100 |
|---|---|---|
| committer | Vasily Gorbik <gor@linux.ibm.com> | 2022-03-27 22:18:39 +0200 |
| commit | 708b13763920ab3c191b31da555f2d90eef4c618 (patch) | |
| tree | 630387a974eaca87727952030397b4191f33d90a /arch/s390 | |
| parent | s390/unwind: recover kretprobe modified return address in stacktrace (diff) | |
| download | linux-708b13763920ab3c191b31da555f2d90eef4c618.tar.xz linux-708b13763920ab3c191b31da555f2d90eef4c618.zip | |
s390/unwind: avoid duplicated unwinding entries for kretprobes
Currently when unwinding starts from pt_regs or encounters pt_regs along
the way unwinder tries to yield 2 unwinding entries:
1. (reliable) ip1: pt_regs->psw.addr, sp1: regs->gprs[15]
2. (non-reliable) ip2: sp1->gprs[8] (r14), sp2: regs->gprs[15]
In case of kretprobes those are identical and serves no other purpose
than causing confusion over duplicated entries and cause kprobes tests
to fail. So, skip a duplicate non-reliable entry in this case.
With that kretprobes and unwinder implementation now comply with
ARCH_CORRECT_STACKTRACE_ON_KRETPROBE.
Reviewed-by: Tobias Huschle <huschle@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Diffstat (limited to 'arch/s390')
| -rw-r--r-- | arch/s390/Kconfig | 1 | ||||
| -rw-r--r-- | arch/s390/kernel/unwind_bc.c | 4 |
2 files changed, 3 insertions, 2 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 9b80e8bed3f6..77b5a03de13a 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -58,6 +58,7 @@ config S390 select ALTERNATE_USER_ADDRESS_SPACE select ARCH_32BIT_USTAT_F_TINODE select ARCH_BINFMT_ELF_STATE + select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM select ARCH_ENABLE_MEMORY_HOTREMOVE select ARCH_ENABLE_SPLIT_PMD_PTLOCK if PGTABLE_LEVELS > 2 diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c index 984970389bab..0ece156fdd7c 100644 --- a/arch/s390/kernel/unwind_bc.c +++ b/arch/s390/kernel/unwind_bc.c @@ -64,8 +64,8 @@ bool unwind_next_frame(struct unwind_state *state) ip = READ_ONCE_NOCHECK(sf->gprs[8]); reliable = false; regs = NULL; - if (!__kernel_text_address(ip)) { - /* skip bogus %r14 */ + /* skip bogus %r14 or if is the same as regs->psw.addr */ + if (!__kernel_text_address(ip) || state->ip == unwind_recover_ret_addr(state, ip)) { state->regs = NULL; return unwind_next_frame(state); } |