diff options
| author | Masami Hiramatsu <mhiramat@kernel.org> | 2026-07-14 10:10:14 +0900 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-07-14 22:43:40 +0900 |
| commit | 1a0ffe10bfb91efc730f2d34c6875c1084b0a462 (patch) | |
| tree | eb7b786d74180008cbb851fa08bd5313de310129 /tools/testing | |
| parent | 47e4ec68716624642f7108535960835bae7eff13 (diff) | |
| download | linux-1a0ffe10bfb91efc730f2d34c6875c1084b0a462.tar.gz linux-1a0ffe10bfb91efc730f2d34c6875c1084b0a462.zip | |
tracing/probes: Eliminate recursion in parse_probe_arg()
To avoid potential stack overflows on limited kernel stacks, convert
parse_probe_arg() from a recursive function into a loop-based
implementation with a simple local state stack.
Since recursion is eliminated using a loop with a fixed-size
stack in the context, this restricts the dereference nesting
depth. The maximum nesting depth of dereferences is now restricted
to the same limit as typecasts (TRACEPROBE_MAX_NESTED_LEVEL, which
is 8) and reports the same TOO_MANY_NESTED error. Update ftrace
selftests to reflect this restriction and simplify the checks.
Note that this change slightly alters the behavior of nested
dereferencing in fetcharg. Previously, dereferencing without BTF
allowed for up to 14 levels of nesting, whereas dereferencing
with BTF was limited to 3 levels. With this change, the nesting
depth is now limited to 8 levels in both cases.
Link: https://lore.kernel.org/all/178399141396.27810.5390060618628718661.stgit@devnote2/
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Diffstat (limited to 'tools/testing')
3 files changed, 5 insertions, 5 deletions
diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc index 984ab94df213..384209968325 100644 --- a/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc +++ b/tools/testing/selftests/ftrace/test.d/dynevent/fprobe_syntax_errors.tc @@ -60,7 +60,7 @@ check_error 'f vfs_read ^&1' # BAD_FETCH_ARG # We've introduced this limitation with array support if grep -q ' <type>\\\[<array-size>\\\]' README; then -check_error 'f vfs_read +0(^+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(@0))))))))))))))' # TOO_MANY_OPS? +check_error 'f vfs_read +0(+0(+0(+0(+0(+0(+0(+0(^+0(@0)))))))))' # TOO_MANY_NESTED check_error 'f vfs_read +0(@11):u8[10^' # ARRAY_NO_CLOSE check_error 'f vfs_read +0(@11):u8[10]^a' # BAD_ARRAY_SUFFIX check_error 'f vfs_read +0(@11):u8[^10a]' # BAD_ARRAY_NUM @@ -114,7 +114,7 @@ check_error 'f vfs_read file^-.foo' # BAD_HYPHEN check_error 'f vfs_read ^file:string' # BAD_TYPE4STR if grep -qF "[(structname" README ; then check_error 'f vfs_read arg1=(task_struct)file^' # TYPECAST_REQ_FIELD -check_error 'f vfs_read arg1=(a)((b)((c)(^(d)file->d)->c)->b)->a' # TOO_MANY_NESTED +check_error 'f vfs_read arg1=(a)((b)((c)((d)((e)((f)((g)((h)(^(i)file->i)->h)->g)->f)->e)->d)->c)->b)->a' # TOO_MANY_NESTED check_error 'f vfs_read arg1=(task_struct,^in_execve)file->comm' # TYPECAST_NOT_ALIGNED check_error 'f vfs_read arg1=(task_struct,^foo_bar)file->pid' # NO_BTF_FIELD check_error 'f vfs_read arg1=(^task_struct1234)file->pid' # NO_PTR_STRCT diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc index 2d0905b2c8b7..72b8652df9ba 100644 --- a/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc +++ b/tools/testing/selftests/ftrace/test.d/dynevent/tprobe_syntax_errors.tc @@ -46,7 +46,7 @@ check_error 't kfree ^&1' # BAD_FETCH_ARG # We've introduced this limitation with array support if grep -q ' <type>\\\[<array-size>\\\]' README; then -check_error 't kfree +0(^+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(@0))))))))))))))' # TOO_MANY_OPS? +check_error 't kfree +0(+0(+0(+0(+0(+0(+0(+0(^+0(@0)))))))))' # TOO_MANY_NESTED check_error 't kfree +0(@11):u8[10^' # ARRAY_NO_CLOSE check_error 't kfree +0(@11):u8[10]^a' # BAD_ARRAY_SUFFIX check_error 't kfree +0(@11):u8[^10a]' # BAD_ARRAY_NUM diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc index d28f63b7e8a9..b0e6b80ccb01 100644 --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_syntax_errors.tc @@ -56,7 +56,7 @@ check_error 'p vfs_read ^&1' # BAD_FETCH_ARG # We've introduced this limitation with array support if grep -q ' <type>\\\[<array-size>\\\]' README; then -check_error 'p vfs_read +0(^+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(+0(@0))))))))))))))' # TOO_MANY_OPS? +check_error 'p vfs_read +0(+0(+0(+0(+0(+0(+0(+0(^+0(@0)))))))))' # TOO_MANY_NESTED check_error 'p vfs_read +0(@11):u8[10^' # ARRAY_NO_CLOSE check_error 'p vfs_read +0(@11):u8[10]^a' # BAD_ARRAY_SUFFIX check_error 'p vfs_read +0(@11):u8[^10a]' # BAD_ARRAY_NUM @@ -117,7 +117,7 @@ check_error 'p kfree ^$arg10' # NO_BTFARG (exceed the number of parameters) check_error 'r kfree ^$retval' # NO_RETVAL if grep -qF "[(structname" README ; then check_error 'p vfs_read arg1=(task_struct)file^' # TYPECAST_REQ_FIELD -check_error 'p vfs_read arg1=(a)((b)((c)(^(d)file->d)->c)->b)->a' # TOO_MANY_NESTED +check_error 'p vfs_read arg1=(a)((b)((c)((d)((e)((f)((g)((h)(^(i)file->i)->h)->g)->f)->e)->d)->c)->b)->a' # TOO_MANY_NESTED check_error 'p vfs_read arg1=(task_struct,^in_execve)file->comm' # TYPECAST_NOT_ALIGNED check_error 'p vfs_read arg1=(task_struct,^foo_bar)file->pid' # NO_BTF_FIELD check_error 'p vfs_read arg1=(^task_struct1234)file->pid' # NO_PTR_STRCT |