| Message ID | 20210614120907.1952321-1-dja@axtens.net (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
| Series | [v2] powerpc: make stack walking KASAN-safe | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (c53db722ec7ab3ebf29ecf61e922820f31e5284b) |
| snowpatch_ozlabs/build-ppc64le | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64be | success | Build succeeded |
| snowpatch_ozlabs/build-ppc64e | success | Build succeeded |
| snowpatch_ozlabs/build-pmac32 | success | Build succeeded |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 39 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
On Mon, 14 Jun 2021 22:09:07 +1000, Daniel Axtens wrote: > Make our stack-walking code KASAN-safe by using __no_sanitize_address. > Generic code, arm64, s390 and x86 all make accesses unchecked for similar > sorts of reasons: when unwinding a stack, we might touch memory that KASAN > has marked as being out-of-bounds. In ppc64 KASAN development, I hit this > sometimes when checking for an exception frame - because we're checking > an arbitrary offset into the stack frame. > > [...] Applied to powerpc/next. [1/1] powerpc: make stack walking KASAN-safe https://git.kernel.org/powerpc/c/b112fb913b5b5705db22efa90ec60f42518934af cheers
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 89e34aa273e2..3464064a0b8b 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -2121,8 +2121,9 @@ unsigned long get_wchan(struct task_struct *p) static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH; -void show_stack(struct task_struct *tsk, unsigned long *stack, - const char *loglvl) +void __no_sanitize_address show_stack(struct task_struct *tsk, + unsigned long *stack, + const char *loglvl) { unsigned long sp, ip, lr, newsp; int count = 0; diff --git a/arch/powerpc/kernel/stacktrace.c b/arch/powerpc/kernel/stacktrace.c index 1deb1bf331dd..1961e6d5e33b 100644 --- a/arch/powerpc/kernel/stacktrace.c +++ b/arch/powerpc/kernel/stacktrace.c @@ -23,8 +23,8 @@ #include <asm/paca.h> -void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, - struct task_struct *task, struct pt_regs *regs) +void __no_sanitize_address arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, + struct task_struct *task, struct pt_regs *regs) { unsigned long sp; @@ -61,8 +61,8 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, * * If the task is not 'current', the caller *must* ensure the task is inactive. */ -int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, - void *cookie, struct task_struct *task) +int __no_sanitize_address arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, + void *cookie, struct task_struct *task) { unsigned long sp; unsigned long newsp; diff --git a/arch/powerpc/perf/callchain.c b/arch/powerpc/perf/callchain.c index 6c028ee513c0..082f6d0308a4 100644 --- a/arch/powerpc/perf/callchain.c +++ b/arch/powerpc/perf/callchain.c @@ -40,7 +40,7 @@ static int valid_next_sp(unsigned long sp, unsigned long prev_sp) return 0; } -void +void __no_sanitize_address perf_callchain_kernel(struct perf_callchain_entry_ctx *entry, struct pt_regs *regs) { unsigned long sp, next_sp;
Make our stack-walking code KASAN-safe by using __no_sanitize_address. Generic code, arm64, s390 and x86 all make accesses unchecked for similar sorts of reasons: when unwinding a stack, we might touch memory that KASAN has marked as being out-of-bounds. In ppc64 KASAN development, I hit this sometimes when checking for an exception frame - because we're checking an arbitrary offset into the stack frame. See commit 20955746320e ("s390/kasan: avoid false positives during stack unwind"), commit bcaf669b4bdb ("arm64: disable kasan when accessing frame->fp in unwind_frame"), commit 91e08ab0c851 ("x86/dumpstack: Prevent KASAN false positive warnings") and commit 6e22c8366416 ("tracing, kasan: Silence Kasan warning in check_stack of stack_tracer"). Cc: Naveen N. Rao <naveen.n.rao@linux.ibm.com> Signed-off-by: Daniel Axtens <dja@axtens.net> --- v2: Use __no_sanitize_address, thanks Naveen --- arch/powerpc/kernel/process.c | 5 +++-- arch/powerpc/kernel/stacktrace.c | 8 ++++---- arch/powerpc/perf/callchain.c | 2 +- 3 files changed, 8 insertions(+), 7 deletions(-)