* Re: [PATCH mm-unstable v18 12/14] mm/khugepaged: avoid unnecessary mTHP collapse attempts
From: Lance Yang @ 2026-05-31 7:31 UTC (permalink / raw)
To: npache
Cc: linux-doc, linux-kernel, linux-mm, linux-trace-kernel, aarcange,
akpm, anshuman.khandual, apopple, baohua, baolin.wang, byungchul,
catalin.marinas, cl, corbet, dave.hansen, david, dev.jain, gourry,
hannes, hughd, jack, jackmanb, jannh, jglisse, joshua.hahnjy, kas,
lance.yang, liam, ljs, mathieu.desnoyers, matthew.brost, mhiramat,
mhocko, peterx, pfalcato, rakie.kim, raquini, rdunlap,
richard.weiyang, rientjes, rostedt, rppt, ryan.roberts, shivankg,
sunnanyong, surenb, thomas.hellstrom, tiwai, usamaarif642, vbabka,
vishal.moola, wangkefeng.wang, will, willy, yang, ying.huang, ziy,
zokeefe, usama.arif
In-Reply-To: <20260522150009.121603-13-npache@redhat.com>
On Fri, May 22, 2026 at 09:00:07AM -0600, Nico Pache wrote:
>There are cases where, if an attempted collapse fails, all subsequent
>orders are guaranteed to also fail. Avoid these collapse attempts by
>bailing out early.
>
>Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
>Acked-by: Usama Arif <usama.arif@linux.dev>
>Acked-by: David Hildenbrand (Arm) <david@kernel.org>
>Signed-off-by: Nico Pache <npache@redhat.com>
>---
> mm/khugepaged.c | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
>diff --git a/mm/khugepaged.c b/mm/khugepaged.c
>index d3d7db8be26c..15b7298bc225 100644
>--- a/mm/khugepaged.c
>+++ b/mm/khugepaged.c
>@@ -1535,9 +1535,31 @@ static int mthp_collapse(struct mm_struct *mm, struct vm_area_struct *vma,
> collapse_address = address + offset * PAGE_SIZE;
> ret = collapse_huge_page(mm, collapse_address, referenced,
> unmapped, cc, order);
>- if (ret == SCAN_SUCCEED) {
>+
>+ switch (ret) {
>+ /* Cases where we continue to next collapse candidate */
>+ case SCAN_SUCCEED:
> collapsed += nr_ptes;
>+ fallthrough;
>+ case SCAN_PTE_MAPPED_HUGEPAGE:
> continue;
>+ /* Cases where lower orders might still succeed */
>+ case SCAN_LACK_REFERENCED_PAGE:
>+ case SCAN_EXCEED_NONE_PTE:
>+ case SCAN_EXCEED_SWAP_PTE:
>+ case SCAN_EXCEED_SHARED_PTE:
>+ case SCAN_PAGE_LOCK:
>+ case SCAN_PAGE_COUNT:
>+ case SCAN_PAGE_NULL:
>+ case SCAN_DEL_PAGE_LRU:
>+ case SCAN_PTE_NON_PRESENT:
>+ case SCAN_PTE_UFFD_WP:
>+ case SCAN_ALLOC_HUGE_PAGE_FAIL:
Nit: shouldn't SCAN_CGROUP_CHARGE_FAIL go with SCAN_ALLOC_HUGE_PAGE_FAIL
here?
If charging the current order fails, a smaller order might still fit :)
Cheers, Lance
>+ case SCAN_PAGE_LAZYFREE:
>+ goto next_order;
>+ /* Cases where no further collapse is possible */
>+ default:
>+ return collapsed;
> }
> }
>
>--
>2.54.0
>
>
^ permalink raw reply
* Re: [PATCH mm-unstable v18 11/14] mm/khugepaged: Introduce mTHP collapse support
From: Lance Yang @ 2026-05-31 7:18 UTC (permalink / raw)
To: npache
Cc: linux-doc, linux-kernel, linux-mm, linux-trace-kernel, aarcange,
akpm, anshuman.khandual, apopple, baohua, baolin.wang, byungchul,
catalin.marinas, cl, corbet, dave.hansen, david, dev.jain, gourry,
hannes, hughd, jack, jackmanb, jannh, jglisse, joshua.hahnjy, kas,
lance.yang, liam, ljs, mathieu.desnoyers, matthew.brost, mhiramat,
mhocko, peterx, pfalcato, rakie.kim, raquini, rdunlap,
richard.weiyang, rientjes, rostedt, rppt, ryan.roberts, shivankg,
sunnanyong, surenb, thomas.hellstrom, tiwai, usamaarif642, vbabka,
vishal.moola, wangkefeng.wang, will, willy, yang, ying.huang, ziy,
zokeefe
In-Reply-To: <20260522150009.121603-12-npache@redhat.com>
On Fri, May 22, 2026 at 09:00:06AM -0600, Nico Pache wrote:
[...]
>@@ -1587,10 +1749,11 @@ static enum scan_result collapse_scan_pmd(struct mm_struct *mm,
> if (result == SCAN_SUCCEED) {
> /* collapse_huge_page expects the lock to be dropped before calling */
> mmap_read_unlock(mm);
>- result = collapse_huge_page(mm, start_addr, referenced,
>- unmapped, cc, HPAGE_PMD_ORDER);
>- /* collapse_huge_page will return with the mmap_lock released */
>+ nr_collapsed = mthp_collapse(mm, vma, start_addr, referenced,
>+ unmapped, cc, enabled_orders);
>+ /* mmap_lock was released above, set lock_dropped */
> *lock_dropped = true;
>+ result = nr_collapsed ? SCAN_SUCCEED : SCAN_FAIL;
Hmm ... don't we lose the allocation-failure result here?
Previously collapse_scan_pmd() propagated SCAN_ALLOC_HUGE_PAGE_FAIL from
collapse_huge_page(), so khugepaged would call khugepaged_alloc_sleep()
in khugepaged_do_scan().
Now if allocation fails and nr_collapsed stays 0, we just return
SCAN_FAIL. So we won't back off via khugepaged_alloc_sleep() anymore?
Cheers, Lance
^ permalink raw reply
* Re: PATCH v7] tracing/eprobes: Allow use of BTF names to dereference pointers
From: Masami Hiramatsu @ 2026-05-31 1:14 UTC (permalink / raw)
To: Steven Rostedt
Cc: LKML, Linux trace kernel, Mathieu Desnoyers, Mark Rutland,
Peter Zijlstra, Namhyung Kim, Takaya Saeki, Douglas Raillard,
Tom Zanussi, Andrew Morton, Thomas Gleixner, Ian Rogers,
Jiri Olsa
In-Reply-To: <20260530110754.14870622@gandalf.local.home>
On Sat, 30 May 2026 11:07:54 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Sat, 30 May 2026 23:14:27 +0900
> Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
>
> > Thanks, and Sashiko reviewed this.
> >
> > https://sashiko.dev/#/patchset/20260529110442.0967a64c%40fedora
> >
> > I think both comments are valid, especially, second one is important.
>
> Hmm, comment below.
>
> >
> > BTW, I updated probes/fixes. Could you also update this and rebase
> > on probes/fixes branch?
> >
> > I'm working on the nesting and container_of support patches which
> > are on top of this.
>
> OK, I'll make sure to use your probes branch. Which one should I use? your
> probes/for-next or probes/urgent?
Ah, probes/fixes. (I think I need to update probes/for-next to rebase on it)
>
> As for sashiko's comments:
>
> > commit c8393ea9936934c16ba2881d9e7b3cce86c678ff
> > Author: Steven Rostedt <rostedt@goodmis.org>
> > [PATCH v7] tracing/eprobes: Allow use of BTF names to dereference pointers
> > This commit introduces syntax to allow event probes to typecast pointer
> > fields to a structure using BTF. This enables dereferencing structures
> > using BTF names rather than having to manually calculate offsets.
> > > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> > > index 39f040c863e85..0e87409a44033 100644
> > > --- a/kernel/trace/trace_probe.c
> > > +++ b/kernel/trace/trace_probe.c
> > [ ... ]
> > > @@ -640,7 +673,7 @@ static int parse_btf_arg(char *varname,
> > > int i, is_ptr, ret;
> > > u32 tid;
> > >
> > > - if (WARN_ON_ONCE(!ctx->funcname))
> > > + if (WARN_ON_ONCE(!ctx->funcname && !(ctx->flags & TPARG_FL_TEVENT)))
> > > return -EINVAL;
> > >
> > > is_ptr = split_next_field(varname, &field, ctx);
> > > @@ -653,6 +686,16 @@ static int parse_btf_arg(char *varname,
> > > return -EOPNOTSUPP;
> > > }
> > >
> > > + if (ctx->flags & TPARG_FL_TEVENT) {
> > > + ret = parse_trace_event(varname, code, ctx);
> > > + if (ret < 0)
> > > + return ret;
>
> > Does this silently drop the error on parsing failure?
> > If parse_trace_event() fails and returns -EINVAL, it appears this path
> > returns the error without logging it.
> > Unlike parse_probe_vars(), which explicitly logs the failure when
> > parse_trace_event() fails, this path bypasses the log. Could this make
> > it difficult to debug invalid typecast expressions since nothing is written
> > to tracing/error_log?
>
> Hmm, I guess I can put an error log here, as this is a unique path.
Yeah, just adding trace_probe_log_err(ctx->offset, BAD_VAR) seems OK.
>
> > > + if (WARN_ON_ONCE(!(ctx->flags & TPARG_FL_TYPECAST)))
> > > + return -EINVAL;
> > > + type = ctx->last_struct;
> > > + goto found_type;
> > > + }
> > > +
> > > if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
> > > code->op = FETCH_OP_RETVAL;
> > [ ... ]
> > > @@ -758,7 +802,71 @@ static int parse_btf_bitfield(struct fetch_insn **pcode,
> > > return 0;
> > > }
> > >
> > > -#else
> > > +static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx)
> > [ ... ]
> > > +static int handle_typecast(char *arg, struct fetch_insn **pcode,
> > > + struct fetch_insn *end,
> > > + struct traceprobe_parse_context *ctx)
> > > +{
> > > + char *tmp;
> > > + int ret;
> > > +
> > > + /* Currently this only works for eprobes */
> > > + if (!(ctx->flags & TPARG_FL_TEVENT)) {
> > > + trace_probe_log_err(ctx->offset, TYPECAST_NOT_EVENT);
> > > + return -EINVAL;
> > > + }
> > > +
> > > + tmp = strchr(arg, ')');
> > > + if (!tmp) {
> > > + trace_probe_log_err(ctx->offset + strlen(arg),
> > > + DEREF_OPEN_BRACE);
> > > + return -EINVAL;
> > > + }
> > > + *tmp = '\0';
> > > + ret = query_btf_struct(arg + 1, ctx);
> > > + *tmp = ')';
> > > +
> > > + if (ret < 0) {
> > > + trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT);
> > > + ret = -EINVAL;
> > > + goto out_put;
> > > + }
> > > +
> > > + ctx->flags |= TPARG_FL_TYPECAST;
> > > + tmp++;
> > > +
> > > + ctx->offset += tmp - arg;
> > > + ret = parse_btf_arg(tmp, pcode, end, ctx);
> > > + ctx->flags &= ~TPARG_FL_TYPECAST;
> > > + ctx->last_struct = NULL;
> > > +out_put:
> > > + btf_put(ctx->struct_btf);
>
> > Does this prematurely release the BTF struct reference?
> > If TPARG_FL_TYPECAST is unset here and ctx->struct_btf is put, won't
> > later steps in traceprobe_parse_probe_arg_body() (like
> > find_fetch_type_from_btf_type()) fail to properly infer struct field sizes?
> > When ctx_btf(ctx) is called later without TPARG_FL_TYPECAST set, it
> > will evaluate to ctx->btf (which is NULL for eprobes).
> > Could this potentially lead to silent defaults, such as 64-bit reads for
> > smaller fields, or fail to inject pointer dereferences for string fields,
> > while also leaving ctx->last_type pointing to a prematurely released BTF
> > object?
>
> Does this mean we need to set ctx->last_type to NULL here too?
No, since the member we refer can be different from unsigned long.
When we don't have ":type" suffix, we use BTF type information to
decide appropriate type.
>
> Because everything above is pretty much the expected behavior. The put is
> *not* premature. The last_struct and struct_btf are both set to NULL. I
> guess the only thing missing is to reset last_type as well.
No, as I explained, the last_type is used to determine the member type
when user does not specify the ":type" suffix.
So, what we need to do is deferring the btf_put(struct_btf) as below:
(no build test yet.)
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index adaa1e4fbdd6..9a73c49e22df 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -538,6 +538,10 @@ static void clear_btf_context(struct traceprobe_parse_context *ctx)
ctx->params = NULL;
ctx->nr_params = 0;
}
+ if (ctx->struct_btf) {
+ btf_put(ctx->struct_btf);
+ ctx->struct_btf = NULL;
+ }
}
/* Return 1 if the field separator is arrow operator ('->') */
@@ -802,22 +806,18 @@ static int parse_btf_bitfield(struct fetch_insn **pcode,
static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx)
{
+ struct btf *btf = NULL;
int id;
- if (!ctx->struct_btf) {
- struct btf *btf;
-
- id = bpf_find_btf_id(sname, BTF_KIND_STRUCT, &btf);
- if (id < 0)
- return id;
- ctx->struct_btf = btf;
- } else {
- id = btf_find_by_name_kind(ctx->struct_btf, sname, BTF_KIND_STRUCT);
- if (id < 0)
- return id;
+ if (ctx->struct_btf) {
+ btf_put(ctx->struct_btf);
+ ctx->struct_btf = NULL;
}
- ctx->last_struct = btf_type_by_id(ctx->struct_btf, id);
+ id = bpf_find_btf_id(sname, BTF_KIND_STRUCT, &btf);
+ if (id < 0)
+ return id;
+ ctx->struct_btf = btf;
return 0;
}
@@ -846,8 +846,7 @@ static int handle_typecast(char *arg, struct fetch_insn **pcode,
if (ret < 0) {
trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT);
- ret = -EINVAL;
- goto out_put;
+ return ret;
}
ctx->flags |= TPARG_FL_TYPECAST;
@@ -857,9 +856,6 @@ static int handle_typecast(char *arg, struct fetch_insn **pcode,
ret = parse_btf_arg(tmp, pcode, end, ctx);
ctx->flags &= ~TPARG_FL_TYPECAST;
ctx->last_struct = NULL;
-out_put:
- btf_put(ctx->struct_btf);
- ctx->struct_btf = NULL;
return ret;
}
Thanks!
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply related
* Re: [PATCH] tracing: fix CFI violation in probestub helper
From: Steven Rostedt @ 2026-05-30 22:57 UTC (permalink / raw)
To: David Laight
Cc: Peter Zijlstra, Eva Kurchatova, mhiramat, linux-trace-kernel,
linux-kernel, mathieu.desnoyers, jpoimboe, samitolvanen
In-Reply-To: <20260530221921.50d958cf@pumpkin>
On Sat, 30 May 2026 22:19:21 +0100
David Laight <david.laight.linux@gmail.com> wrote:
> > +/* \
> > + * The probestub is only used for tprobes and not referenced \
> > + * anywhere else. This causes objtool to think it's not called \
> > + * at all and will add it to the seal list which will remove \
> > + * the ENDBR causing issues if a tprobe is ever used. \
> > + */ \
>
> Isn't the sense of that all wrong?
The above is still correct. It just expresses what the probestub is
used for.
> Maybe:
> Annotate the protosub 'CFI_NOSEAL' to stop objtool requesting the
> kernel remove the ENDBR because the only references to the
> function are in the __tracepoint section that objtool doesn't scan.
I do agree that your version is a bit more concise.
Thanks,
-- Steve
^ permalink raw reply
* Re: [PATCH] tracing: fix CFI violation in probestub helper
From: David Laight @ 2026-05-30 21:19 UTC (permalink / raw)
To: Steven Rostedt
Cc: Peter Zijlstra, Eva Kurchatova, mhiramat, linux-trace-kernel,
linux-kernel, mathieu.desnoyers, jpoimboe, samitolvanen
In-Reply-To: <20260529195134.37d4f5cc@fedora>
On Fri, 29 May 2026 19:51:34 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 29 May 2026 22:08:26 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > On Thu, May 28, 2026 at 04:49:02PM -0400, Steven Rostedt wrote:
> > > On Sun, 24 May 2026 18:43:01 +0300
> > > Eva Kurchatova <eva.kurchatova@virtuozzo.com> wrote:
> > >
> > > > When multiple callbacks are registered on the same tracepoint, probestub
> > > > will be indirectly called via traceiter helper.
> > > >
> > > > Pointer to probestub callback resides in __tracepoints section, which is
> > > > excluded from ENDBR checks in objtool. Pointers to regfunc/unregfunc
> > > > callbacks reside in extended structure however, which is not affected.
> > > >
> > > > Registering multiple callbacks will result in a #CP exception due to
> > > > missed ENDBR in __probestub helper on a CFI-enabled machine.
> > > >
> > > > Fix this by adding CFI_NOSEAL annotation to probestub declaration.
> > > >
> > > > Fixes: d5173f753750 ("objtool: Exclude __tracepoints data from ENDBR checks")
> > > > Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
>
> >
> > The only place the function address lives is in that __tracepoint
> > section. Since that is explicitly excluded by objtool, it figures there
> > are no actual references to __probestub and the function goes on the
> > seal list and the kernel explicitly scribbles the ENDBR on boot.
> >
> > Then, if it ever gets used on an IBT enabled host, *boom*.
>
> That makes much more sense.
>
> >
> > I agree it would've perhaps been clearer if there was part of a splat in
> > the changelog, but the issue is real afaict.
> >
> > Also, I do think this:
> >
> > > > @@ -356,6 +357,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
> > > > void __probestub_##_name(void *__data, proto) \
> > > > { \
> > > > } \
> > > > + CFI_NOSEAL(__probestub_##_name); \
> > > > DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
> > > >
> > > > #define DEFINE_TRACE_FN(_name, _reg, _unreg, _proto, _args) \
> >
> > could do with a comment, explaining why it wants the NOSEAL.
>
> Yes.
>
> Thus, the above change log is totally incorrect and should be updated to:
>
> tprobes uses a stub function of the tracepoint to allow fprobes to
> attach to the tracepoint call site and have access to its arguments.
> The stub function is called __probestub_##_name() and is only
> referenced as a pointer in the tracepoint structure so that the
> tprobe can have access to it.
>
> The issue is that the probstub function is only referenced in the
> __tracepoint section and objtool thinks nothing calls it. Since it
> explicitly excludes the __tracepoint section, objtool thinks there
> are no callers so it puts the probstub function into the seal list
> and then the kernel scrubs its ENDBR on boot.
>
> This becomes an issue if someone were to use a tprobe which will
> register the probestub as a callback to the tracepoint so that a
> fprobe may attach to it and get access to the arguments. Without the
> ENDBR it will make the kernel go BOOM!
>
>
> Then have a comment in the patch with:
>
> void __probestub_##_name(void *__data, proto) \
> { \
> } \
> +/* \
> + * The probestub is only used for tprobes and not referenced \
> + * anywhere else. This causes objtool to think it's not called \
> + * at all and will add it to the seal list which will remove \
> + * the ENDBR causing issues if a tprobe is ever used. \
> + */ \
Isn't the sense of that all wrong?
Maybe:
Annotate the protosub 'CFI_NOSEAL' to stop objtool requesting the
kernel remove the ENDBR because the only references to the
function are in the __tracepoint section that objtool doesn't scan.
-- David
> +CFI_NOSEAL(__probestub_##_name); \
> DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
>
>
> -- Steve
>
^ permalink raw reply
* Re: [PATCH] tracing: fix CFI violation in probestub helper
From: Masami Hiramatsu @ 2026-05-30 15:52 UTC (permalink / raw)
To: Steven Rostedt
Cc: Peter Zijlstra, Eva Kurchatova, mhiramat, linux-trace-kernel,
linux-kernel, mathieu.desnoyers, jpoimboe, samitolvanen
In-Reply-To: <20260529195134.37d4f5cc@fedora>
On Fri, 29 May 2026 19:51:34 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Fri, 29 May 2026 22:08:26 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > On Thu, May 28, 2026 at 04:49:02PM -0400, Steven Rostedt wrote:
> > > On Sun, 24 May 2026 18:43:01 +0300
> > > Eva Kurchatova <eva.kurchatova@virtuozzo.com> wrote:
> > >
> > > > When multiple callbacks are registered on the same tracepoint, probestub
> > > > will be indirectly called via traceiter helper.
> > > >
> > > > Pointer to probestub callback resides in __tracepoints section, which is
> > > > excluded from ENDBR checks in objtool. Pointers to regfunc/unregfunc
> > > > callbacks reside in extended structure however, which is not affected.
> > > >
> > > > Registering multiple callbacks will result in a #CP exception due to
> > > > missed ENDBR in __probestub helper on a CFI-enabled machine.
> > > >
> > > > Fix this by adding CFI_NOSEAL annotation to probestub declaration.
> > > >
> > > > Fixes: d5173f753750 ("objtool: Exclude __tracepoints data from ENDBR checks")
> > > > Signed-off-by: Eva Kurchatova <eva.kurchatova@virtuozzo.com>
>
> >
> > The only place the function address lives is in that __tracepoint
> > section. Since that is explicitly excluded by objtool, it figures there
> > are no actual references to __probestub and the function goes on the
> > seal list and the kernel explicitly scribbles the ENDBR on boot.
> >
> > Then, if it ever gets used on an IBT enabled host, *boom*.
>
> That makes much more sense.
Ah, I got it.
>
> >
> > I agree it would've perhaps been clearer if there was part of a splat in
> > the changelog, but the issue is real afaict.
> >
> > Also, I do think this:
> >
> > > > @@ -356,6 +357,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p)
> > > > void __probestub_##_name(void *__data, proto) \
> > > > { \
> > > > } \
> > > > + CFI_NOSEAL(__probestub_##_name); \
> > > > DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
> > > >
> > > > #define DEFINE_TRACE_FN(_name, _reg, _unreg, _proto, _args) \
> >
> > could do with a comment, explaining why it wants the NOSEAL.
>
> Yes.
>
> Thus, the above change log is totally incorrect and should be updated to:
>
> tprobes uses a stub function of the tracepoint to allow fprobes to
> attach to the tracepoint call site and have access to its arguments.
> The stub function is called __probestub_##_name() and is only
> referenced as a pointer in the tracepoint structure so that the
> tprobe can have access to it.
>
> The issue is that the probstub function is only referenced in the
> __tracepoint section and objtool thinks nothing calls it. Since it
> explicitly excludes the __tracepoint section, objtool thinks there
> are no callers so it puts the probstub function into the seal list
> and then the kernel scrubs its ENDBR on boot.
>
> This becomes an issue if someone were to use a tprobe which will
> register the probestub as a callback to the tracepoint so that a
> fprobe may attach to it and get access to the arguments. Without the
> ENDBR it will make the kernel go BOOM!
>
>
> Then have a comment in the patch with:
>
> void __probestub_##_name(void *__data, proto) \
> { \
> } \
> +/* \
> + * The probestub is only used for tprobes and not referenced \
> + * anywhere else. This causes objtool to think it's not called \
> + * at all and will add it to the seal list which will remove \
> + * the ENDBR causing issues if a tprobe is ever used. \
> + */ \
> +CFI_NOSEAL(__probestub_##_name); \
> DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name);
This looks good to me. Eva, can you update the patch?
Thanks for fix.
>
>
> -- Steve
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: PATCH v7] tracing/eprobes: Allow use of BTF names to dereference pointers
From: Steven Rostedt @ 2026-05-30 15:07 UTC (permalink / raw)
To: Masami Hiramatsu (Google)
Cc: LKML, Linux trace kernel, Mathieu Desnoyers, Mark Rutland,
Peter Zijlstra, Namhyung Kim, Takaya Saeki, Douglas Raillard,
Tom Zanussi, Andrew Morton, Thomas Gleixner, Ian Rogers,
Jiri Olsa
In-Reply-To: <20260530231427.b079fefffc724a40082cd64b@kernel.org>
On Sat, 30 May 2026 23:14:27 +0900
Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> Thanks, and Sashiko reviewed this.
>
> https://sashiko.dev/#/patchset/20260529110442.0967a64c%40fedora
>
> I think both comments are valid, especially, second one is important.
Hmm, comment below.
>
> BTW, I updated probes/fixes. Could you also update this and rebase
> on probes/fixes branch?
>
> I'm working on the nesting and container_of support patches which
> are on top of this.
OK, I'll make sure to use your probes branch. Which one should I use? your
probes/for-next or probes/urgent?
As for sashiko's comments:
> commit c8393ea9936934c16ba2881d9e7b3cce86c678ff
> Author: Steven Rostedt <rostedt@goodmis.org>
> [PATCH v7] tracing/eprobes: Allow use of BTF names to dereference pointers
> This commit introduces syntax to allow event probes to typecast pointer
> fields to a structure using BTF. This enables dereferencing structures
> using BTF names rather than having to manually calculate offsets.
> > diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> > index 39f040c863e85..0e87409a44033 100644
> > --- a/kernel/trace/trace_probe.c
> > +++ b/kernel/trace/trace_probe.c
> [ ... ]
> > @@ -640,7 +673,7 @@ static int parse_btf_arg(char *varname,
> > int i, is_ptr, ret;
> > u32 tid;
> >
> > - if (WARN_ON_ONCE(!ctx->funcname))
> > + if (WARN_ON_ONCE(!ctx->funcname && !(ctx->flags & TPARG_FL_TEVENT)))
> > return -EINVAL;
> >
> > is_ptr = split_next_field(varname, &field, ctx);
> > @@ -653,6 +686,16 @@ static int parse_btf_arg(char *varname,
> > return -EOPNOTSUPP;
> > }
> >
> > + if (ctx->flags & TPARG_FL_TEVENT) {
> > + ret = parse_trace_event(varname, code, ctx);
> > + if (ret < 0)
> > + return ret;
> Does this silently drop the error on parsing failure?
> If parse_trace_event() fails and returns -EINVAL, it appears this path
> returns the error without logging it.
> Unlike parse_probe_vars(), which explicitly logs the failure when
> parse_trace_event() fails, this path bypasses the log. Could this make
> it difficult to debug invalid typecast expressions since nothing is written
> to tracing/error_log?
Hmm, I guess I can put an error log here, as this is a unique path.
> > + if (WARN_ON_ONCE(!(ctx->flags & TPARG_FL_TYPECAST)))
> > + return -EINVAL;
> > + type = ctx->last_struct;
> > + goto found_type;
> > + }
> > +
> > if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
> > code->op = FETCH_OP_RETVAL;
> [ ... ]
> > @@ -758,7 +802,71 @@ static int parse_btf_bitfield(struct fetch_insn **pcode,
> > return 0;
> > }
> >
> > -#else
> > +static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx)
> [ ... ]
> > +static int handle_typecast(char *arg, struct fetch_insn **pcode,
> > + struct fetch_insn *end,
> > + struct traceprobe_parse_context *ctx)
> > +{
> > + char *tmp;
> > + int ret;
> > +
> > + /* Currently this only works for eprobes */
> > + if (!(ctx->flags & TPARG_FL_TEVENT)) {
> > + trace_probe_log_err(ctx->offset, TYPECAST_NOT_EVENT);
> > + return -EINVAL;
> > + }
> > +
> > + tmp = strchr(arg, ')');
> > + if (!tmp) {
> > + trace_probe_log_err(ctx->offset + strlen(arg),
> > + DEREF_OPEN_BRACE);
> > + return -EINVAL;
> > + }
> > + *tmp = '\0';
> > + ret = query_btf_struct(arg + 1, ctx);
> > + *tmp = ')';
> > +
> > + if (ret < 0) {
> > + trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT);
> > + ret = -EINVAL;
> > + goto out_put;
> > + }
> > +
> > + ctx->flags |= TPARG_FL_TYPECAST;
> > + tmp++;
> > +
> > + ctx->offset += tmp - arg;
> > + ret = parse_btf_arg(tmp, pcode, end, ctx);
> > + ctx->flags &= ~TPARG_FL_TYPECAST;
> > + ctx->last_struct = NULL;
> > +out_put:
> > + btf_put(ctx->struct_btf);
> Does this prematurely release the BTF struct reference?
> If TPARG_FL_TYPECAST is unset here and ctx->struct_btf is put, won't
> later steps in traceprobe_parse_probe_arg_body() (like
> find_fetch_type_from_btf_type()) fail to properly infer struct field sizes?
> When ctx_btf(ctx) is called later without TPARG_FL_TYPECAST set, it
> will evaluate to ctx->btf (which is NULL for eprobes).
> Could this potentially lead to silent defaults, such as 64-bit reads for
> smaller fields, or fail to inject pointer dereferences for string fields,
> while also leaving ctx->last_type pointing to a prematurely released BTF
> object?
Does this mean we need to set ctx->last_type to NULL here too?
Because everything above is pretty much the expected behavior. The put is
*not* premature. The last_struct and struct_btf are both set to NULL. I
guess the only thing missing is to reset last_type as well.
-- Steve
> > + ctx->struct_btf = NULL;
> > + return ret;
> > +}
> > +
> > +#else /* !CONFIG_PROBE_EVENTS_BTF_ARGS */
^ permalink raw reply
* Re: [RFC PATCH] trace: Introduce a new filter_pred "caller"
From: Steven Rostedt @ 2026-05-30 14:55 UTC (permalink / raw)
To: chenjun (AM)
Cc: Masami Hiramatsu (Google), mathieu.desnoyers@efficios.com,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org
In-Reply-To: <b72c8c6ce638449ea9e99e892a25dc86@huawei.com>
On Sat, 30 May 2026 10:46:35 +0000
"chenjun (AM)" <chenjun102@huawei.com> wrote:
> > Hi Chen,
> >
> > Do you plan on sending updates to address the comments that Masami and
> > I have made?
> >
> > -- Steve
>
> Hi，
>
> Sorry, I've been busy with other things lately. I'll release the patch
> v2 next week.
>
> One thing I'd like to confirm is whether to use `called_within` as the
> filter name.
I was talking with my wife about this (who isn't technical at all, but
wanted to get her thoughts on terminology) and we came up with simply using
"within".
That is, we want the event to trigger if it is called "within" a function.
Hence, if you use:
echo 'within=="$function_name"' > events/../filter
I think it's pretty obvious to what it means.
Thanks,
-- Steve
^ permalink raw reply
* Re: [PATCH v2] tracing/osnoise: Array printk init and cleanup
From: Steven Rostedt @ 2026-05-30 14:51 UTC (permalink / raw)
To: Crystal Wood
Cc: linux-trace-kernel, John Kacur, Tomas Glozar, Costa Shulyupin,
Wander Lairson Costa, sashiko-bot, sashiko-reviews
In-Reply-To: <b555e6ba6f723c244edc88afbc6383022d51ed3c.camel@redhat.com>
On Fri, 29 May 2026 22:33:37 -0500
Crystal Wood <crwood@redhat.com> wrote:
> > > diff --git a/kernel/trace/trace_osnoise.c b/kernel/trace/trace_osnoise.c
> > > index 75678053b21c..bda1e0e0d2e1 100644
> > > --- a/kernel/trace/trace_osnoise.c
> > > +++ b/kernel/trace/trace_osnoise.c
> > > @@ -476,8 +476,11 @@ static void print_osnoise_headers(struct seq_file *s)
> > > \
> > > rcu_read_lock(); \
> > > list_for_each_entry_rcu(inst, &osnoise_instances, list) { \
> > > + if (trace_array_get(inst->tr) < 0) \
> > > + continue; \
> > > buffer = inst->tr->array_buffer.buffer; \
> > > trace_array_printk_buf(buffer, _THIS_IP_, msg); \
> > > + trace_array_put(inst->tr); \
> > > } \
> > > rcu_read_unlock(); \
> > > osnoise_data.tainted = true; \
> >
> > OK, I'll prepare a v3.
>
> Many osnoise_taint() callers, as well as timerlat_dump_stack(), can have
> preemption disabled, so the mutex in trace_array_get() won't work.
Right. OK, so another solution is to simply call synchronize_rcu() instead
of the kvfree_rcu_mightsleep(inst);
synchronize_rcu();
kvfree(inst);
Then there should not be any race, because the rmdir will have to wait for
the synchronization before finishing. This isn't something people should be
running a lot of, so I don't think it would cause too much pain in waiting
to unregister the osnoise tracer.
-- Steve
^ permalink raw reply
* [PATCH v3 13/13] verification/rvgen: Generate cleanup hook for per-obj monitor
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Nam Cao, Wen Yang
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Per-object monitors can allocate memory dynamically and such memory is
required for the lifetime of the object, then it should be freed with
the appropriate call.
Force the generation scripts to add a cleanup function the user will
need to wire to the appropriate event (e.g. sched_process_exit for
tasks). This can be safely removed if the object will never cease to
exist before disabling the monitor (e.g. if following only static
variables).
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
tools/verification/rvgen/rvgen/dot2k.py | 15 +++++++++++++++
1 file changed, 15 insertions(+)
diff --git a/tools/verification/rvgen/rvgen/dot2k.py b/tools/verification/rvgen/rvgen/dot2k.py
index 110cfd69e..3060aa4b9 100644
--- a/tools/verification/rvgen/rvgen/dot2k.py
+++ b/tools/verification/rvgen/rvgen/dot2k.py
@@ -17,6 +17,9 @@ from .automata import _EventConstraintKey, _StateConstraintKey, AutomataError
class dot2k(Monitor, Dot2c):
template_dir = "dot2k"
+ # only needed for the per-obj cleanup hook
+ cleanup_marker = "obj_cleanup"
+
def __init__(self, file_path, MonitorType, extra_params={}):
self.monitor_type = MonitorType
Monitor.__init__(self, extra_params)
@@ -56,18 +59,30 @@ class dot2k(Monitor, Dot2c):
buff.append(f"\tda_{handle}({event}{self.enum_suffix});")
buff.append("}")
buff.append("")
+ if self.monitor_type == "per_obj":
+ buff.append("/* XXX: obj is being destroyed, remove if not required (e.g. obj is static) */")
+ buff.append(f"static void handle_{self.cleanup_marker}(void *data, /* XXX: fill header */)")
+ buff.append("{")
+ buff.append("\tint id = /* XXX: how do I get the id? */;")
+ buff.append("\tda_destroy_storage(id);")
+ buff.append("}")
+ buff.append("")
return '\n'.join(buff)
def fill_tracepoint_attach_probe(self) -> str:
buff = []
for event in self.events:
buff.append(f"\trv_attach_trace_probe(\"{self.name}\", /* XXX: tracepoint */, handle_{event});")
+ if self.monitor_type == "per_obj":
+ buff.append(f"\trv_attach_trace_probe(\"{self.name}\", /* XXX: cleanup tracepoint */, handle_{self.cleanup_marker});")
return '\n'.join(buff)
def fill_tracepoint_detach_helper(self) -> str:
buff = []
for event in self.events:
buff.append(f"\trv_detach_trace_probe(\"{self.name}\", /* XXX: tracepoint */, handle_{event});")
+ if self.monitor_type == "per_obj":
+ buff.append(f"\trv_detach_trace_probe(\"{self.name}\", /* XXX: cleanup tracepoint */, handle_{self.cleanup_marker});")
return '\n'.join(buff)
def fill_model_h_header(self) -> list[str]:
--
2.54.0
^ permalink raw reply related
* [PATCH v3 12/13] rv: Fix read_lock scope in per-task DA cleanup
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
The da_monitor_reset_all() function for per-task monitors takes
tasklist_lock while iterating over tasks, then keeps it also while
iterating over idle tasks (one per CPU). The latter is not necessary
since the lock needs to guard only for_each_process_thread().
Use a scoped_guard for more compact syntax and adjust the scope only
where the lock is necessary.
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index ae8c35fcb..f4fc22cac 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -294,12 +294,12 @@ static void da_monitor_reset_all(void)
struct task_struct *g, *p;
int cpu;
- read_lock(&tasklist_lock);
- for_each_process_thread(g, p)
- da_monitor_reset(da_get_monitor(p));
+ scoped_guard(read_lock, &tasklist_lock) {
+ for_each_process_thread(g, p)
+ da_monitor_reset(da_get_monitor(p));
+ }
for_each_present_cpu(cpu)
da_monitor_reset(da_get_monitor(idle_task(cpu)));
- read_unlock(&tasklist_lock);
}
/*
--
2.54.0
^ permalink raw reply related
* [PATCH v3 11/13] verification/rvgen: Fix suffix strip in dot2k
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Nam Cao, Wen Yang
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
__start_to_invariant_check() and __get_constraint_env() parse the
environment variable's name from sources that have it padded with the
monitor name. This is removed using rstrip(), which is not meant to
strip a substring but rather a set of characters.
Use removesuffix() to actually get rid of the trailing _<monitor name>.
Fixes: a82adadb16894 ("verification/rvgen: Add support for Hybrid Automata")
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
tools/verification/rvgen/rvgen/dot2k.py | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/verification/rvgen/rvgen/dot2k.py b/tools/verification/rvgen/rvgen/dot2k.py
index e6f476b90..110cfd69e 100644
--- a/tools/verification/rvgen/rvgen/dot2k.py
+++ b/tools/verification/rvgen/rvgen/dot2k.py
@@ -215,14 +215,14 @@ class ha2k(dot2k):
def __get_constraint_env(self, constr: str) -> str:
"""Extract the second argument from an ha_ function"""
env = constr.split("(")[1].split()[1].rstrip(")").rstrip(",")
- assert env.rstrip(f"_{self.name}") in self.envs
+ assert env.removesuffix(f"_{self.name}") in self.envs
return env
def __start_to_invariant_check(self, constr: str) -> str:
# by default assume the timer has ns expiration
env = self.__get_constraint_env(constr)
clock_type = "ns"
- if self.env_types.get(env.rstrip(f"_{self.name}")) == "j":
+ if self.env_types.get(env.removesuffix(f"_{self.name}")) == "j":
clock_type = "jiffy"
return f"return ha_check_invariant_{clock_type}(ha_mon, {env}, time_ns)"
--
2.54.0
^ permalink raw reply related
* [PATCH v3 10/13] rv: Use 0 to check preemption enabled in opid
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, Masami Hiramatsu,
linux-trace-kernel
Cc: Nam Cao, Wen Yang
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Tracepoint handlers no longer run with preemption disabled by default
since a46023d5616 ("tracing: Guard __DECLARE_TRACE() use of
__DO_TRACE_CALL() with SRCU-fast"), the opid monitor should now count 1
in the preemption count as preemption disabled.
Change the rule for preempt_off to preempt > 0.
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
kernel/trace/rv/monitors/opid/opid.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/kernel/trace/rv/monitors/opid/opid.c b/kernel/trace/rv/monitors/opid/opid.c
index 2922318c6..3b6a85e81 100644
--- a/kernel/trace/rv/monitors/opid/opid.c
+++ b/kernel/trace/rv/monitors/opid/opid.c
@@ -22,14 +22,8 @@ static u64 ha_get_env(struct ha_monitor *ha_mon, enum envs_opid env, u64 time_ns
if (env == irq_off_opid)
return irqs_disabled();
else if (env == preempt_off_opid) {
- /*
- * If CONFIG_PREEMPTION is enabled, then the tracepoint itself disables
- * preemption (adding one to the preempt_count). Since we are
- * interested in the preempt_count at the time the tracepoint was
- * hit, we consider 1 as still enabled.
- */
if (IS_ENABLED(CONFIG_PREEMPTION))
- return (preempt_count() & PREEMPT_MASK) > 1;
+ return (preempt_count() & PREEMPT_MASK) > 0;
return true;
}
return ENV_INVALID_VALUE;
--
2.54.0
^ permalink raw reply related
* [PATCH v3 09/13] rv: Prevent task migration while handling per-CPU events
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Tracepoint handlers are fully preemptible after a46023d5616 ("tracing:
Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast"). When
a per-CPU monitor handles an event, it retrieves the monitor state using
a per-CPU pointer. If the event itself doesn't disable preemption, the
task can migrate to a different CPU and we risk updating the wrong
monitor.
Mitigate this by explicitly disabling task migration before acquiring
the monitor pointer. This cannot guarantee the monitor runs on the
correct CPU but reduces the race condition window and prevents warnings.
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index 03c1150b1..ae8c35fcb 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -194,6 +194,10 @@ static inline void da_monitor_destroy(void)
da_monitor_sync_hook();
}
+#ifndef da_implicit_guard
+#define da_implicit_guard()
+#endif
+
#elif RV_MON_TYPE == RV_MON_PER_CPU
/*
* Functions to define, init and get a per-cpu monitor.
@@ -244,6 +248,10 @@ static inline void da_monitor_destroy(void)
da_monitor_sync_hook();
}
+#ifndef da_implicit_guard
+#define da_implicit_guard() guard(migrate)()
+#endif
+
#elif RV_MON_TYPE == RV_MON_PER_TASK
/*
* Functions to define, init and get a per-task monitor.
@@ -700,6 +708,7 @@ static inline bool __da_handle_start_run_event(struct da_monitor *da_mon,
*/
static inline void da_handle_event(enum events event)
{
+ da_implicit_guard();
__da_handle_event(da_get_monitor(), event, 0);
}
@@ -715,6 +724,7 @@ static inline void da_handle_event(enum events event)
*/
static inline bool da_handle_start_event(enum events event)
{
+ da_implicit_guard();
return __da_handle_start_event(da_get_monitor(), event, 0);
}
@@ -726,6 +736,7 @@ static inline bool da_handle_start_event(enum events event)
*/
static inline bool da_handle_start_run_event(enum events event)
{
+ da_implicit_guard();
return __da_handle_start_run_event(da_get_monitor(), event, 0);
}
--
2.54.0
^ permalink raw reply related
* [PATCH v3 08/13] rv: Ensure synchronous cleanup for HA monitors
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Nam Cao, Wen Yang
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
HA monitors may start timers, all cleanup functions currently stop the
timers asynchronously to avoid sleeping in the wrong context.
Nothing makes sure running callbacks terminate on cleanup.
Run the entire HA timer callback in an RCU read-side critical section,
this way we can simply synchronize_rcu() with any pending timer and are
sure any cleanup using kfree_rcu() runs after callbacks terminated.
Additionally make sure any unlikely callback running late won't run any
code if the monitor is marked as disabled or if destruction started.
Use memory barriers to serialise with racing resets.
Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Fixes: 4a24127bd6cb ("rv: Add support for per-object monitors in DA/HA")
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 26 +++++++++++++++++++++-----
include/rv/ha_monitor.h | 28 +++++++++++++++++++++++++---
2 files changed, 46 insertions(+), 8 deletions(-)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index 60dc39f26..03c1150b1 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -57,6 +57,15 @@ static struct rv_monitor rv_this;
#define da_monitor_reset_hook(da_mon)
#endif
+/*
+ * Hook to allow the implementation of hybrid automata: define it with a
+ * function that waits for the termination of all monitors background
+ * activities (e.g. all timers). This hook can sleep.
+ */
+#ifndef da_monitor_sync_hook
+#define da_monitor_sync_hook()
+#endif
+
/*
* Type for the target id, default to int but can be overridden.
* A long type can work as hash table key (PER_OBJ) but will be downgraded to
@@ -83,7 +92,8 @@ static inline void da_monitor_reset(struct da_monitor *da_mon)
{
da_monitor_reset_hook(da_mon);
WRITE_ONCE(da_mon->monitoring, 0);
- da_mon->curr_state = model_get_initial_state();
+ /* Pair with load in __ha_monitor_timer_callback */
+ smp_store_release(&da_mon->curr_state, model_get_initial_state());
}
/*
@@ -181,6 +191,7 @@ static inline int da_monitor_init(void)
static inline void da_monitor_destroy(void)
{
da_monitor_reset_all();
+ da_monitor_sync_hook();
}
#elif RV_MON_TYPE == RV_MON_PER_CPU
@@ -230,6 +241,7 @@ static inline int da_monitor_init(void)
static inline void da_monitor_destroy(void)
{
da_monitor_reset_all();
+ da_monitor_sync_hook();
}
#elif RV_MON_TYPE == RV_MON_PER_TASK
@@ -317,6 +329,7 @@ static inline void da_monitor_destroy(void)
tracepoint_synchronize_unregister();
da_monitor_reset_all();
+ da_monitor_sync_hook();
rv_put_task_monitor_slot(task_mon_slot);
task_mon_slot = RV_PER_TASK_MONITOR_INIT;
@@ -495,10 +508,9 @@ static void da_monitor_reset_all(void)
struct da_monitor_storage *mon_storage;
int bkt;
- rcu_read_lock();
+ guard(rcu)();
hash_for_each_rcu(da_monitor_ht, bkt, mon_storage, node)
da_monitor_reset(&mon_storage->rv.da_mon);
- rcu_read_unlock();
}
static inline int da_monitor_init(void)
@@ -514,13 +526,17 @@ static inline void da_monitor_destroy(void)
int bkt;
tracepoint_synchronize_unregister();
+ scoped_guard(rcu) {
+ hash_for_each_rcu(da_monitor_ht, bkt, mon_storage, node) {
+ da_monitor_reset_hook(&mon_storage->rv.da_mon);
+ }
+ }
+ da_monitor_sync_hook();
/*
* This function is called after all probes are disabled and no longer
* pending, we can safely assume no concurrent user.
*/
- synchronize_rcu();
hash_for_each_safe(da_monitor_ht, bkt, tmp, mon_storage, node) {
- da_monitor_reset_hook(&mon_storage->rv.da_mon);
hash_del_rcu(&mon_storage->node);
kfree(mon_storage);
}
diff --git a/include/rv/ha_monitor.h b/include/rv/ha_monitor.h
index 0aeb6bc38..86bd1cab8 100644
--- a/include/rv/ha_monitor.h
+++ b/include/rv/ha_monitor.h
@@ -37,6 +37,7 @@ static bool ha_monitor_handle_constraint(struct da_monitor *da_mon,
#define da_monitor_event_hook ha_monitor_handle_constraint
#define da_monitor_init_hook ha_monitor_init_env
#define da_monitor_reset_hook ha_monitor_reset_env
+#define da_monitor_sync_hook() synchronize_rcu()
#if !defined(HA_SKIP_AUTO_CLEANUP) && RV_MON_TYPE == RV_MON_PER_TASK
/*
@@ -137,11 +138,13 @@ static enum hrtimer_restart ha_monitor_timer_callback(struct hrtimer *hrtimer);
#endif /* HA_CLK_NS */
static bool ha_mon_initializing;
+static bool ha_mon_destroying;
static int ha_monitor_init(void)
{
int ret;
+ WRITE_ONCE(ha_mon_destroying, false);
ha_mon_initializing = true;
ret = da_monitor_init();
if (ret == 0)
@@ -152,6 +155,7 @@ static int ha_monitor_init(void)
static void ha_monitor_destroy(void)
{
+ WRITE_ONCE(ha_mon_destroying, true);
ha_monitor_disable_hook();
da_monitor_destroy();
}
@@ -302,12 +306,30 @@ static bool ha_monitor_handle_constraint(struct da_monitor *da_mon,
return false;
}
+/*
+ * __ha_monitor_timer_callback - generic callback representation
+ *
+ * This callback runs in an RCU read-side critical section to allow the
+ * destruction sequence to easily synchronize_rcu() with all pending timers
+ * after asynchronously disabling them. The ha_mon_destroying check ensures
+ * any callback entering the RCU section after synchronize_rcu() completes
+ * will see the flag and bail out immediately.
+ */
static inline void __ha_monitor_timer_callback(struct ha_monitor *ha_mon)
{
- enum states curr_state = READ_ONCE(ha_mon->da_mon.curr_state);
DECLARE_SEQ_BUF(env_string, ENV_BUFFER_SIZE);
- u64 time_ns = ha_get_ns();
-
+ enum states curr_state;
+ u64 time_ns;
+
+ guard(rcu)();
+ if (unlikely(READ_ONCE(ha_mon_destroying)))
+ return;
+ /* Ensure consistent curr_state if we race with da_monitor_reset */
+ curr_state = smp_load_acquire(&ha_mon->da_mon.curr_state);
+ if (unlikely(!da_monitor_handling_event(&ha_mon->da_mon)))
+ return;
+
+ time_ns = ha_get_ns();
ha_get_env_string(&env_string, ha_mon, time_ns);
ha_react(curr_state, EVENT_NONE, env_string.buffer);
ha_trace_error_env(ha_mon, model_get_state_name(curr_state),
--
2.54.0
^ permalink raw reply related
* [PATCH v3 07/13] rv: Add automatic cleanup handlers for per-task HA monitors
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Nam Cao, Wen Yang
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Hybrid automata monitors may start timers, depending on the model, these
may remain active on an exiting task and cause false positives or even
access freed memory.
Add an enable/disable hook in the HA code, currently only populated by
the per-task handler for registration and deregistration.
This hooks to the sched_process_exit event and ensures the timer is
stopped for every exiting task. The handler is enabled automatically but
may be disabled, for instance if the monitor uses the event for another
purpose (but should still manually ensure timers are stopped).
Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/ha_monitor.h | 45 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/include/rv/ha_monitor.h b/include/rv/ha_monitor.h
index ad3347af1..0aeb6bc38 100644
--- a/include/rv/ha_monitor.h
+++ b/include/rv/ha_monitor.h
@@ -28,6 +28,7 @@ static inline void ha_monitor_init_env(struct da_monitor *da_mon);
static inline void ha_monitor_reset_env(struct da_monitor *da_mon);
static inline void ha_setup_timer(struct ha_monitor *ha_mon);
static inline bool ha_cancel_timer(struct ha_monitor *ha_mon);
+static inline void ha_cancel_timer_sync(struct ha_monitor *ha_mon);
static bool ha_monitor_handle_constraint(struct da_monitor *da_mon,
enum states curr_state,
enum events event,
@@ -37,6 +38,26 @@ static bool ha_monitor_handle_constraint(struct da_monitor *da_mon,
#define da_monitor_init_hook ha_monitor_init_env
#define da_monitor_reset_hook ha_monitor_reset_env
+#if !defined(HA_SKIP_AUTO_CLEANUP) && RV_MON_TYPE == RV_MON_PER_TASK
+/*
+ * Automatic cleanup handlers for per-task HA monitors, only skip if you know
+ * what you are doing (e.g. you want to implement cleanup manually in another
+ * handler doing more things).
+ */
+static void ha_handle_sched_process_exit(void *data, struct task_struct *p,
+ bool group_dead);
+
+#define ha_monitor_enable_hook() \
+ rv_attach_trace_probe(__stringify(MONITOR_NAME), sched_process_exit, \
+ ha_handle_sched_process_exit)
+#define ha_monitor_disable_hook() \
+ rv_detach_trace_probe(__stringify(MONITOR_NAME), sched_process_exit, \
+ ha_handle_sched_process_exit)
+#else
+#define ha_monitor_enable_hook() ((void)0)
+#define ha_monitor_disable_hook() ((void)0)
+#endif
+
#include <rv/da_monitor.h>
#include <linux/seq_buf.h>
@@ -123,12 +144,15 @@ static int ha_monitor_init(void)
ha_mon_initializing = true;
ret = da_monitor_init();
+ if (ret == 0)
+ ha_monitor_enable_hook();
ha_mon_initializing = false;
return ret;
}
static void ha_monitor_destroy(void)
{
+ ha_monitor_disable_hook();
da_monitor_destroy();
}
@@ -229,6 +253,18 @@ static inline void ha_trace_error_env(struct ha_monitor *ha_mon,
{
CONCATENATE(trace_error_env_, MONITOR_NAME)(id, curr_state, event, env);
}
+
+#if !defined(HA_SKIP_AUTO_CLEANUP) && RV_MON_TYPE == RV_MON_PER_TASK
+static void ha_handle_sched_process_exit(void *data, struct task_struct *p,
+ bool group_dead)
+{
+ struct da_monitor *da_mon = da_get_monitor(p);
+
+ if (likely(!ha_monitor_uninitialized(da_mon)))
+ ha_cancel_timer_sync(to_ha_monitor(da_mon));
+}
+#endif
+
#endif /* RV_MON_TYPE */
/*
@@ -441,6 +477,10 @@ static inline bool ha_cancel_timer(struct ha_monitor *ha_mon)
{
return timer_delete(&ha_mon->timer);
}
+static inline void ha_cancel_timer_sync(struct ha_monitor *ha_mon)
+{
+ timer_delete_sync(&ha_mon->timer);
+}
#elif HA_TIMER_TYPE == HA_TIMER_HRTIMER
/*
* Helper functions to handle the monitor timer.
@@ -492,6 +532,10 @@ static inline bool ha_cancel_timer(struct ha_monitor *ha_mon)
{
return hrtimer_try_to_cancel(&ha_mon->hrtimer) == 1;
}
+static inline void ha_cancel_timer_sync(struct ha_monitor *ha_mon)
+{
+ hrtimer_cancel(&ha_mon->hrtimer);
+}
#else /* HA_TIMER_NONE */
/*
* Start function is intentionally not defined, monitors using timers must
@@ -502,6 +546,7 @@ static inline bool ha_cancel_timer(struct ha_monitor *ha_mon)
{
return false;
}
+static inline void ha_cancel_timer_sync(struct ha_monitor *ha_mon) { }
#endif
#endif
--
2.54.0
^ permalink raw reply related
* [PATCH v3 06/13] rv: Do not rely on clean monitor when initialising HA
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, Masami Hiramatsu,
linux-trace-kernel
Cc: Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Hybrid Automata monitors hook into the DA implementation when doing
da_monitor_reset(). This function is called both on initialisation and
teardown, HA monitors try to cancel a timer only when it's initialised
relying on the da_mon->monitoring flag. This flag could however be
corrupted during initialisation. This happens for instance on per-task
monitors that share the same storage with different type of monitors
like LTL or in case of races during a previous teardown.
Stop relying on the monitoring flag during initialisation, assume that
can have any value, so skip timer cancellation in any case when a local
flag is set. New monitors (e.g. new tasks) are always zero-initialised
so they are safe.
Reported-by: Wen Yang <wen.yang@linux.dev>
Closes: https://lore.kernel.org/lkml/d02c656aada7d071f083460a5c9a454363669b61.1778522945.git.wen.yang@linux.dev
Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/ha_monitor.h | 31 ++++++++++++++++++-
kernel/trace/rv/monitors/nomiss/nomiss.c | 4 +--
kernel/trace/rv/monitors/opid/opid.c | 4 +--
kernel/trace/rv/monitors/stall/stall.c | 4 +--
.../rvgen/rvgen/templates/dot2k/main.c | 4 +--
5 files changed, 38 insertions(+), 9 deletions(-)
diff --git a/include/rv/ha_monitor.h b/include/rv/ha_monitor.h
index d59507e8c..ad3347af1 100644
--- a/include/rv/ha_monitor.h
+++ b/include/rv/ha_monitor.h
@@ -115,6 +115,35 @@ static enum hrtimer_restart ha_monitor_timer_callback(struct hrtimer *hrtimer);
#define ha_get_ns() 0
#endif /* HA_CLK_NS */
+static bool ha_mon_initializing;
+
+static int ha_monitor_init(void)
+{
+ int ret;
+
+ ha_mon_initializing = true;
+ ret = da_monitor_init();
+ ha_mon_initializing = false;
+ return ret;
+}
+
+static void ha_monitor_destroy(void)
+{
+ da_monitor_destroy();
+}
+
+/*
+ * ha_monitor_uninitialized - are fields like the timer initialized?
+ *
+ * On a clean monitor, we can assume an active monitor (monitoring) is
+ * initialized, however the monitoring field cannot be trusted during
+ * initialization.
+ */
+static inline bool ha_monitor_uninitialized(struct da_monitor *da_mon)
+{
+ return ha_mon_initializing || !da_monitoring(da_mon);
+}
+
/* Should be supplied by the monitor */
static u64 ha_get_env(struct ha_monitor *ha_mon, enum envs env, u64 time_ns);
static bool ha_verify_constraint(struct ha_monitor *ha_mon,
@@ -159,7 +188,7 @@ static inline void ha_monitor_reset_env(struct da_monitor *da_mon)
struct ha_monitor *ha_mon = to_ha_monitor(da_mon);
/* Initialisation resets the monitor before initialising the timer */
- if (likely(da_monitoring(da_mon)))
+ if (likely(!ha_monitor_uninitialized(da_mon)))
ha_cancel_timer(ha_mon);
}
diff --git a/kernel/trace/rv/monitors/nomiss/nomiss.c b/kernel/trace/rv/monitors/nomiss/nomiss.c
index 31f90f363..8ead8783c 100644
--- a/kernel/trace/rv/monitors/nomiss/nomiss.c
+++ b/kernel/trace/rv/monitors/nomiss/nomiss.c
@@ -227,7 +227,7 @@ static int enable_nomiss(void)
{
int retval;
- retval = da_monitor_init();
+ retval = ha_monitor_init();
if (retval)
return retval;
@@ -263,7 +263,7 @@ static void disable_nomiss(void)
rv_detach_trace_probe("nomiss", sched_switch, handle_sched_switch);
rv_detach_trace_probe("nomiss", sched_wakeup, handle_sched_wakeup);
- da_monitor_destroy();
+ ha_monitor_destroy();
}
static struct rv_monitor rv_this = {
diff --git a/kernel/trace/rv/monitors/opid/opid.c b/kernel/trace/rv/monitors/opid/opid.c
index 4594c7c46..2922318c6 100644
--- a/kernel/trace/rv/monitors/opid/opid.c
+++ b/kernel/trace/rv/monitors/opid/opid.c
@@ -73,7 +73,7 @@ static int enable_opid(void)
{
int retval;
- retval = da_monitor_init();
+ retval = ha_monitor_init();
if (retval)
return retval;
@@ -90,7 +90,7 @@ static void disable_opid(void)
rv_detach_trace_probe("opid", sched_set_need_resched_tp, handle_sched_need_resched);
rv_detach_trace_probe("opid", sched_waking, handle_sched_waking);
- da_monitor_destroy();
+ ha_monitor_destroy();
}
/*
diff --git a/kernel/trace/rv/monitors/stall/stall.c b/kernel/trace/rv/monitors/stall/stall.c
index 9ccfda6b0..3c38fb1a0 100644
--- a/kernel/trace/rv/monitors/stall/stall.c
+++ b/kernel/trace/rv/monitors/stall/stall.c
@@ -103,7 +103,7 @@ static int enable_stall(void)
{
int retval;
- retval = da_monitor_init();
+ retval = ha_monitor_init();
if (retval)
return retval;
@@ -120,7 +120,7 @@ static void disable_stall(void)
rv_detach_trace_probe("stall", sched_switch, handle_sched_switch);
rv_detach_trace_probe("stall", sched_wakeup, handle_sched_wakeup);
- da_monitor_destroy();
+ ha_monitor_destroy();
}
static struct rv_monitor rv_this = {
diff --git a/tools/verification/rvgen/rvgen/templates/dot2k/main.c b/tools/verification/rvgen/rvgen/templates/dot2k/main.c
index bf0999f66..889446760 100644
--- a/tools/verification/rvgen/rvgen/templates/dot2k/main.c
+++ b/tools/verification/rvgen/rvgen/templates/dot2k/main.c
@@ -35,7 +35,7 @@ static int enable_%%MODEL_NAME%%(void)
{
int retval;
- retval = da_monitor_init();
+ retval = %%MONITOR_CLASS%%_monitor_init();
if (retval)
return retval;
@@ -50,7 +50,7 @@ static void disable_%%MODEL_NAME%%(void)
%%TRACEPOINT_DETACH%%
- da_monitor_destroy();
+ %%MONITOR_CLASS%%_monitor_destroy();
}
/*
--
2.54.0
^ permalink raw reply related
* [PATCH v3 05/13] rv: Fix monitor start ordering and memory ordering for monitoring flag
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
From: Wen Yang <wen.yang@linux.dev>
da_monitor_start() set monitoring=1 before calling da_monitor_init_hook(),
may racing with the sched_switch handler:
da_monitor_start() sched_switch handler
------------------------- ---------------------------------
da_mon->monitoring = 1;
if (da_monitoring(da_mon)) /* true */
ha_start_timer_ns(...);
/* hrtimer->base == NULL, crash */
da_monitor_init_hook(da_mon);
/* hrtimer_setup() sets base */
Fix the ordering and pair with release/acquire semantics:
da_monitor_init_hook(da_mon);
smp_store_release(&da_mon->monitoring, 1); /* da_monitor_start() */
return smp_load_acquire(&da_mon->monitoring); /* da_monitoring() */
On ARM64 a plain STR + LDR does not form a release-acquire pair, so
the load can observe monitoring=1 while hrtimer->base is still NULL.
The plain accesses are also data races under KCSAN.
Use WRITE_ONCE for the monitoring=0 store in da_monitor_reset() to
cover the reset path.
Fixes: 792575348ff7 ("rv/include: Add deterministic automata monitor definition via C macros")
Signed-off-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Gabriele Monaco <gmonaco@redhat.com>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index a7e103654..60dc39f26 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -82,7 +82,7 @@ static void react(enum states curr_state, enum events event)
static inline void da_monitor_reset(struct da_monitor *da_mon)
{
da_monitor_reset_hook(da_mon);
- da_mon->monitoring = 0;
+ WRITE_ONCE(da_mon->monitoring, 0);
da_mon->curr_state = model_get_initial_state();
}
@@ -95,8 +95,9 @@ static inline void da_monitor_reset(struct da_monitor *da_mon)
static inline void da_monitor_start(struct da_monitor *da_mon)
{
da_mon->curr_state = model_get_initial_state();
- da_mon->monitoring = 1;
da_monitor_init_hook(da_mon);
+ /* Pairs with smp_load_acquire in da_monitoring(). */
+ smp_store_release(&da_mon->monitoring, 1);
}
/*
@@ -104,7 +105,8 @@ static inline void da_monitor_start(struct da_monitor *da_mon)
*/
static inline bool da_monitoring(struct da_monitor *da_mon)
{
- return da_mon->monitoring;
+ /* Pairs with smp_store_release in da_monitor_start(). */
+ return smp_load_acquire(&da_mon->monitoring);
}
/*
--
2.54.0
^ permalink raw reply related
* [PATCH v3 04/13] rv: Ensure all pending probes terminate on per-obj monitor destroy
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
The monitor disable/destroy sequence detaches all probes and resets the
monitor's data, however it doesn't wait for pending probes. This is an
issue with per-object monitors, which free the monitor storage.
Call tracepoint_synchronize_unregister() to make sure to wait for all
pending probes before destroying the monitor storage.
Fixes: 4a24127bd6cb ("rv: Add support for per-object monitors in DA/HA")
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index cc97cc5df..a7e103654 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -511,9 +511,10 @@ static inline void da_monitor_destroy(void)
struct hlist_node *tmp;
int bkt;
+ tracepoint_synchronize_unregister();
/*
- * This function is called after all probes are disabled, we need only
- * worry about concurrency against old events.
+ * This function is called after all probes are disabled and no longer
+ * pending, we can safely assume no concurrent user.
*/
synchronize_rcu();
hash_for_each_safe(da_monitor_ht, bkt, tmp, mon_storage, node) {
--
2.54.0
^ permalink raw reply related
* [PATCH v3 03/13] rv: Prevent in-flight per-task handlers from using invalid slots
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Per-task monitors use a slot in the task_struct->rv[] array and store
that locally (e.g. task_mon_slot), this slot is returned during the
destruction process but currently hanlers can be running while that slot
is returning and this race may lead to accessing an invalid slot.
Synchronise with all in-flight tracepoint handlers using
tracepoint_synchronize_unregister() before returning the slot.
Fixes: f5587d1b6ec9 ("rv: Add Hybrid Automata monitor type")
Fixes: a9769a5b9878 ("rv: Add support for LTL monitors")
Suggested-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 4 ++++
include/rv/ltl_monitor.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index 1459fb3df..cc97cc5df 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -302,6 +302,9 @@ static int da_monitor_init(void)
/*
* da_monitor_destroy - return the allocated slot
+ *
+ * Wait for all in-flight handlers before returning the slot to avoid
+ * out-of-bound accesses.
*/
static inline void da_monitor_destroy(void)
{
@@ -310,6 +313,7 @@ static inline void da_monitor_destroy(void)
return;
}
+ tracepoint_synchronize_unregister();
da_monitor_reset_all();
rv_put_task_monitor_slot(task_mon_slot);
diff --git a/include/rv/ltl_monitor.h b/include/rv/ltl_monitor.h
index eff60cd61..38e792401 100644
--- a/include/rv/ltl_monitor.h
+++ b/include/rv/ltl_monitor.h
@@ -77,6 +77,7 @@ static void ltl_monitor_destroy(void)
{
rv_detach_trace_probe(name, task_newtask, handle_task_newtask);
+ tracepoint_synchronize_unregister();
rv_put_task_monitor_slot(ltl_monitor_slot);
ltl_monitor_slot = RV_PER_TASK_MONITOR_INIT;
}
--
2.54.0
^ permalink raw reply related
* [PATCH v3 02/13] rv: Reset per-task DA monitors before releasing the slot
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, linux-trace-kernel
Cc: stable, Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
Per-task monitors use task_mon_slot to determine which slot in the array
to use for the monitor. During destruction, this slot is returned but
this is done before resetting the monitor. As a result, the monitor's
reset is in fact resetting a slot that is outside of the array
(RV_PER_TASK_MONITOR_INIT).
Release the slot only after the reset to avoid out-of-bound memory
access.
Fixes: f5587d1b6ec93 ("rv: Add Hybrid Automata monitor type")
Cc: stable@vger.kernel.org
Suggested-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
include/rv/da_monitor.h | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/include/rv/da_monitor.h b/include/rv/da_monitor.h
index 39765ff6f..1459fb3df 100644
--- a/include/rv/da_monitor.h
+++ b/include/rv/da_monitor.h
@@ -309,10 +309,11 @@ static inline void da_monitor_destroy(void)
WARN_ONCE(1, "Disabling a disabled monitor: " __stringify(MONITOR_NAME));
return;
}
- rv_put_task_monitor_slot(task_mon_slot);
- task_mon_slot = RV_PER_TASK_MONITOR_INIT;
da_monitor_reset_all();
+
+ rv_put_task_monitor_slot(task_mon_slot);
+ task_mon_slot = RV_PER_TASK_MONITOR_INIT;
}
#elif RV_MON_TYPE == RV_MON_PER_OBJ
--
2.54.0
^ permalink raw reply related
* [PATCH v3 01/13] rv: Fix __user specifier usage in extract_params()
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel, Steven Rostedt, Gabriele Monaco, Masami Hiramatsu,
linux-trace-kernel
Cc: kernel test robot, Wen Yang, Nam Cao
In-Reply-To: <20260530141652.58084-1-gmonaco@redhat.com>
The attributes variables extracted from syscalls in the helper are both
defined with the __user specifier although only the actual pointer to
user data should be marked.
Remove the __user specifier from attr.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202604150820.Ny143u6X-lkp@intel.com
Fixes: b133207deb72 ("rv: Add nomiss deadline monitor")
Reviewed-by: Wen Yang <wen.yang@linux.dev>
Reviewed-by: Nam Cao <namcao@linutronix.de>
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
---
kernel/trace/rv/monitors/deadline/deadline.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/rv/monitors/deadline/deadline.h b/kernel/trace/rv/monitors/deadline/deadline.h
index 0bbfd2543..78fca873d 100644
--- a/kernel/trace/rv/monitors/deadline/deadline.h
+++ b/kernel/trace/rv/monitors/deadline/deadline.h
@@ -95,7 +95,8 @@ static inline u8 get_server_type(struct task_struct *tsk)
static inline int extract_params(struct pt_regs *regs, long id, pid_t *pid_out)
{
size_t size = offsetofend(struct sched_attr, sched_flags);
- struct sched_attr __user *uattr, attr;
+ struct sched_attr __user *uattr;
+ struct sched_attr attr;
int new_policy = -1, ret;
unsigned long args[6];
--
2.54.0
^ permalink raw reply related
* [PATCH v3 00/13] rv: Fixes on Deterministic and Hybrid Automata
From: Gabriele Monaco @ 2026-05-30 14:16 UTC (permalink / raw)
To: linux-kernel
Cc: Gabriele Monaco, Steven Rostedt, Nam Cao, Wen Yang,
linux-trace-kernel
Fix issues that were reported by bots or visible only after integration:
* Make sure timers are always terminated and waited for when disabling
the monitor or when the target terminates
* Run per-cpu monitors with migration disabled since preemption is now
enabled from tracepoints
* Fix a wrong __user specifier in a helper function
* Other cleanup and concurrency issues
Differences since V2 [1]:
* Applied from reviews changes to commit messages
* Rearranged order to put non-fixes and not-reviewed patches in the end
* Synchronise monitors before resetting them to avoid rearming
* Protect against racing timer callbacks during destruction
Differences since V1 [2]:
* Fix memory consistency with timer callbacks racing with resets
* Add per-obj deallocation hook in rvgen generated code
* Do not rely on clean monitor when initialising HA
* Add tracepoint synchronisation before returning per-task slots
* Fix suffix strip in dot2k
* Generate stub deallocation hooks instead of failing build when per-obj
miss those
[1] - https://lore.kernel.org/lkml/20260527062313.39908-1-gmonaco@redhat.com
[2] - https://lore.kernel.org/lkml/20260512140250.262190-1-gmonaco@redhat.com
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nam Cao <namcao@linutronix.de>
Cc: Wen Yang <wen.yang@linux.dev>
Cc: linux-trace-kernel@vger.kernel.org
Gabriele Monaco (12):
rv: Fix __user specifier usage in extract_params()
rv: Reset per-task DA monitors before releasing the slot
rv: Prevent in-flight per-task handlers from using invalid slots
rv: Ensure all pending probes terminate on per-obj monitor destroy
rv: Do not rely on clean monitor when initialising HA
rv: Add automatic cleanup handlers for per-task HA monitors
rv: Ensure synchronous cleanup for HA monitors
rv: Prevent task migration while handling per-CPU events
rv: Use 0 to check preemption enabled in opid
verification/rvgen: Fix suffix strip in dot2k
rv: Fix read_lock scope in per-task DA cleanup
verification/rvgen: Generate cleanup hook for per-obj monitor
Wen Yang (1):
rv: Fix monitor start ordering and memory ordering for monitoring flag
include/rv/da_monitor.h | 67 ++++++++---
include/rv/ha_monitor.h | 104 +++++++++++++++++-
include/rv/ltl_monitor.h | 1 +
kernel/trace/rv/monitors/deadline/deadline.h | 3 +-
kernel/trace/rv/monitors/nomiss/nomiss.c | 4 +-
kernel/trace/rv/monitors/opid/opid.c | 12 +-
kernel/trace/rv/monitors/stall/stall.c | 4 +-
tools/verification/rvgen/rvgen/dot2k.py | 19 +++-
.../rvgen/rvgen/templates/dot2k/main.c | 4 +-
9 files changed, 180 insertions(+), 38 deletions(-)
base-commit: 8fde5d1d47f69db6082dfa34500c27f8485389a5
--
2.54.0
^ permalink raw reply
* Re: PATCH v7] tracing/eprobes: Allow use of BTF names to dereference pointers
From: Masami Hiramatsu @ 2026-05-30 14:14 UTC (permalink / raw)
To: Steven Rostedt
Cc: LKML, Linux trace kernel, Masami Hiramatsu, Mathieu Desnoyers,
Mark Rutland, Peter Zijlstra, Namhyung Kim, Takaya Saeki,
Douglas Raillard, Tom Zanussi, Andrew Morton, Thomas Gleixner,
Ian Rogers, Jiri Olsa
In-Reply-To: <20260529110442.0967a64c@fedora>
On Fri, 29 May 2026 11:04:42 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> From: Steven Rostedt <rostedt@goodmis.org>
>
> Add syntax to the parsing of eprobes to be able to typecast a trace event
> field that is a pointer to a structure.
>
> Currently, a dereference must be a number, where the user has to figure
> out manually the offset of a member of a structure that they want to
> dereference.
>
> But for event probes that records a field that happens to be a pointer to
> a structure, it cannot dereference these values with BTF naming, but
> must use numerical offsets.
>
> For example, to find out what device a sk_buff is pointing to in the
> net_dev_xmit trace event, one must first use gdb to find the offsets of the
> members of the structures:
>
> (gdb) p &((struct sk_buff *)0)->dev
> $1 = (struct net_device **) 0x10
> (gdb) p &((struct net_device *)0)->name
> $2 = (char (*)[16]) 0x118
>
> And then use the raw numbers to dereference:
>
> # echo 'e:xmit net.net_dev_xmit +0x118(+0x10($skbaddr)):string' >> dynamic_events
>
> If BTF is in the kernel, then instead, the skbaddr can be typecast to
> sk_buff and use the normal dereference logic.
>
> # echo 'e:xmit net.net_dev_xmit (sk_buff)skbaddr->dev->name:string' >> dynamic_events
> # echo 1 > events/eprobes/xmit/enable
> # cat trace
> [..]
> sshd-session-1022 [000] b..2. 860.249343: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.250061: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.250142: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.263553: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.283820: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.302716: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.322905: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.342828: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.362268: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.382335: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.400856: xmit: (net.net_dev_xmit) arg1="enp7s0"
> sshd-session-1022 [000] b..2. 860.419893: xmit: (net.net_dev_xmit) arg1="enp7s0"
>
> The syntax is simply: (STRUCT)(FIELD)->MEMBER[->MEMBER..]
>
> Also add comments around the #else and #endif of #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
> to know what they are for.
Thanks, and Sashiko reviewed this.
https://sashiko.dev/#/patchset/20260529110442.0967a64c%40fedora
I think both comments are valid, especially, second one is important.
BTW, I updated probes/fixes. Could you also update this and rebase
on probes/fixes branch?
I'm working on the nesting and container_of support patches which
are on top of this.
Thank you,
>
> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
> ---
> Changes since v6: https://patch.msgid.link/20260521225033.56458336@fedora
>
> - Set ctx->struct_btf to NULL when finished with it in handle_typecast()
> (Sashiko)
>
> - Remove extra unneeded "ret" declaration (Masami Hiramatsu)
>
> - Add a WARN_ON_ONCE() in parse_btf_arg for TEVENT being called without
> TYPECAST being set. (Masami Hiramatsu)
>
> Documentation/trace/eprobetrace.rst | 4 +
> kernel/trace/trace_probe.c | 168 +++++++++++++++++++++++-----
> kernel/trace/trace_probe.h | 7 +-
> 3 files changed, 149 insertions(+), 30 deletions(-)
>
> diff --git a/Documentation/trace/eprobetrace.rst b/Documentation/trace/eprobetrace.rst
> index 89b5157cfab8..fe3602540569 100644
> --- a/Documentation/trace/eprobetrace.rst
> +++ b/Documentation/trace/eprobetrace.rst
> @@ -46,6 +46,10 @@ Synopsis of eprobe_events
> (x8/x16/x32/x64), VFS layer common type(%pd/%pD), "char",
> "string", "ustring", "symbol", "symstr" and "bitfield" are
> supported.
> + (STRUCT)FIELD->MEMBER[->MEMBER] : If BTF is supported, typecast FIELD to
> + a pointer to STRUCT and then derference the pointer defined by
> + ->MEMBER. Note that when this is used, the FIELD name does not
> + need to be prefixed with a '$'.
>
> Types
> -----
> diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
> index e0d3a0da26af..9246e9c3d066 100644
> --- a/kernel/trace/trace_probe.c
> +++ b/kernel/trace/trace_probe.c
> @@ -332,6 +332,25 @@ static int parse_trace_event_arg(char *arg, struct fetch_insn *code,
> return -ENOENT;
> }
>
> +static int parse_trace_event(char *arg, struct fetch_insn *code,
> + struct traceprobe_parse_context *ctx)
> +{
> + int ret;
> +
> + if (code->data)
> + return -EFAULT;
> + ret = parse_trace_event_arg(arg, code, ctx);
> + if (!ret)
> + return 0;
> + if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
> + code->op = FETCH_OP_COMM;
> + return 0;
> + }
> + /* backward compatibility */
> + ctx->offset = 0;
> + return -EINVAL;
> +}
> +
> #ifdef CONFIG_PROBE_EVENTS_BTF_ARGS
>
> static u32 btf_type_int(const struct btf_type *t)
> @@ -376,11 +395,17 @@ static bool btf_type_is_char_array(struct btf *btf, const struct btf_type *type)
> && BTF_INT_BITS(intdata) == 8;
> }
>
> +static struct btf *ctx_btf(struct traceprobe_parse_context *ctx)
> +{
> + return ctx->flags & TPARG_FL_TYPECAST ?
> + ctx->struct_btf : ctx->btf;
> +}
> +
> static int check_prepare_btf_string_fetch(char *typename,
> struct fetch_insn **pcode,
> struct traceprobe_parse_context *ctx)
> {
> - struct btf *btf = ctx->btf;
> + struct btf *btf = ctx_btf(ctx);
>
> if (!btf || !ctx->last_type)
> return 0;
> @@ -554,22 +579,29 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type,
> struct fetch_insn *code = *pcode;
> const struct btf_member *field;
> u32 bitoffs, anon_offs;
> + bool is_struct = ctx->flags & TPARG_FL_TYPECAST;
> + struct btf *btf = ctx_btf(ctx);
> char *next;
> int is_ptr;
> s32 tid;
>
> do {
> - /* Outer loop for solving arrow operator ('->') */
> - if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
> - trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
> - return -EINVAL;
> - }
> - /* Convert a struct pointer type to a struct type */
> - type = btf_type_skip_modifiers(ctx->btf, type->type, &tid);
> - if (!type) {
> - trace_probe_log_err(ctx->offset, BAD_BTF_TID);
> - return -EINVAL;
> + if (!is_struct) {
> + /* Outer loop for solving arrow operator ('->') */
> + if (BTF_INFO_KIND(type->info) != BTF_KIND_PTR) {
> + trace_probe_log_err(ctx->offset, NO_PTR_STRCT);
> + return -EINVAL;
> + }
> +
> + /* Convert a struct pointer type to a struct type */
> + type = btf_type_skip_modifiers(btf, type->type, &tid);
> + if (!type) {
> + trace_probe_log_err(ctx->offset, BAD_BTF_TID);
> + return -EINVAL;
> + }
> }
> + /* Only the first type can skip being a pointer */
> + is_struct = false;
>
> bitoffs = 0;
> do {
> @@ -580,7 +612,7 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type,
> return is_ptr;
>
> anon_offs = 0;
> - field = btf_find_struct_member(ctx->btf, type, fieldname,
> + field = btf_find_struct_member(btf, type, fieldname,
> &anon_offs);
> if (IS_ERR(field)) {
> trace_probe_log_err(ctx->offset, BAD_BTF_TID);
> @@ -602,7 +634,7 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type,
> ctx->last_bitsize = 0;
> }
>
> - type = btf_type_skip_modifiers(ctx->btf, field->type, &tid);
> + type = btf_type_skip_modifiers(btf, field->type, &tid);
> if (!type) {
> trace_probe_log_err(ctx->offset, BAD_BTF_TID);
> return -EINVAL;
> @@ -627,6 +659,7 @@ static int parse_btf_field(char *fieldname, const struct btf_type *type,
> return 0;
> }
>
> +
> static int __store_entry_arg(struct trace_probe *tp, int argnum);
>
> static int parse_btf_arg(char *varname,
> @@ -640,7 +673,7 @@ static int parse_btf_arg(char *varname,
> int i, is_ptr, ret;
> u32 tid;
>
> - if (WARN_ON_ONCE(!ctx->funcname))
> + if (WARN_ON_ONCE(!ctx->funcname && !(ctx->flags & TPARG_FL_TEVENT)))
> return -EINVAL;
>
> is_ptr = split_next_field(varname, &field, ctx);
> @@ -653,6 +686,16 @@ static int parse_btf_arg(char *varname,
> return -EOPNOTSUPP;
> }
>
> + if (ctx->flags & TPARG_FL_TEVENT) {
> + ret = parse_trace_event(varname, code, ctx);
> + if (ret < 0)
> + return ret;
> + if (WARN_ON_ONCE(!(ctx->flags & TPARG_FL_TYPECAST)))
> + return -EINVAL;
> + type = ctx->last_struct;
> + goto found_type;
> + }
> +
> if (ctx->flags & TPARG_FL_RETURN && !strcmp(varname, "$retval")) {
> code->op = FETCH_OP_RETVAL;
> /* Check whether the function return type is not void */
> @@ -709,6 +752,7 @@ static int parse_btf_arg(char *varname,
>
> found:
> type = btf_type_skip_modifiers(ctx->btf, tid, &tid);
> +found_type:
> if (!type) {
> trace_probe_log_err(ctx->offset, BAD_BTF_TID);
> return -EINVAL;
> @@ -727,7 +771,7 @@ static int parse_btf_arg(char *varname,
> static const struct fetch_type *find_fetch_type_from_btf_type(
> struct traceprobe_parse_context *ctx)
> {
> - struct btf *btf = ctx->btf;
> + struct btf *btf = ctx_btf(ctx);
> const char *typestr = NULL;
>
> if (btf && ctx->last_type)
> @@ -758,7 +802,71 @@ static int parse_btf_bitfield(struct fetch_insn **pcode,
> return 0;
> }
>
> -#else
> +static int query_btf_struct(const char *sname, struct traceprobe_parse_context *ctx)
> +{
> + int id;
> +
> + if (!ctx->struct_btf) {
> + struct btf *btf;
> +
> + id = bpf_find_btf_id(sname, BTF_KIND_STRUCT, &btf);
> + if (id < 0)
> + return id;
> + ctx->struct_btf = btf;
> + } else {
> + id = btf_find_by_name_kind(ctx->struct_btf, sname, BTF_KIND_STRUCT);
> + if (id < 0)
> + return id;
> + }
> +
> + ctx->last_struct = btf_type_by_id(ctx->struct_btf, id);
> + return 0;
> +}
> +
> +static int handle_typecast(char *arg, struct fetch_insn **pcode,
> + struct fetch_insn *end,
> + struct traceprobe_parse_context *ctx)
> +{
> + char *tmp;
> + int ret;
> +
> + /* Currently this only works for eprobes */
> + if (!(ctx->flags & TPARG_FL_TEVENT)) {
> + trace_probe_log_err(ctx->offset, TYPECAST_NOT_EVENT);
> + return -EINVAL;
> + }
> +
> + tmp = strchr(arg, ')');
> + if (!tmp) {
> + trace_probe_log_err(ctx->offset + strlen(arg),
> + DEREF_OPEN_BRACE);
> + return -EINVAL;
> + }
> + *tmp = '\0';
> + ret = query_btf_struct(arg + 1, ctx);
> + *tmp = ')';
> +
> + if (ret < 0) {
> + trace_probe_log_err(ctx->offset + 1, NO_PTR_STRCT);
> + ret = -EINVAL;
> + goto out_put;
> + }
> +
> + ctx->flags |= TPARG_FL_TYPECAST;
> + tmp++;
> +
> + ctx->offset += tmp - arg;
> + ret = parse_btf_arg(tmp, pcode, end, ctx);
> + ctx->flags &= ~TPARG_FL_TYPECAST;
> + ctx->last_struct = NULL;
> +out_put:
> + btf_put(ctx->struct_btf);
> + ctx->struct_btf = NULL;
> + return ret;
> +}
> +
> +#else /* !CONFIG_PROBE_EVENTS_BTF_ARGS */
> +
> static void clear_btf_context(struct traceprobe_parse_context *ctx)
> {
> ctx->btf = NULL;
> @@ -794,7 +902,15 @@ static int check_prepare_btf_string_fetch(char *typename,
> return 0;
> }
>
> -#endif
> +static int handle_typecast(char *arg, struct fetch_insn **pcode,
> + struct fetch_insn *end,
> + struct traceprobe_parse_context *ctx)
> +{
> + trace_probe_log_err(ctx->offset, NOSUP_BTFARG);
> + return -EOPNOTSUPP;
> +}
> +
> +#endif /* CONFIG_PROBE_EVENTS_BTF_ARGS */
>
> #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API
>
> @@ -953,18 +1069,9 @@ static int parse_probe_vars(char *orig_arg, const struct fetch_type *t,
> int len;
>
> if (ctx->flags & TPARG_FL_TEVENT) {
> - if (code->data)
> - return -EFAULT;
> - ret = parse_trace_event_arg(arg, code, ctx);
> - if (!ret)
> - return 0;
> - if (strcmp(arg, "comm") == 0 || strcmp(arg, "COMM") == 0) {
> - code->op = FETCH_OP_COMM;
> - return 0;
> - }
> - /* backward compatibility */
> - ctx->offset = 0;
> - goto inval;
> + if (parse_trace_event(arg, code, ctx) < 0)
> + goto inval;
> + return 0;
> }
>
> if (str_has_prefix(arg, "retval")) {
> @@ -1231,6 +1338,9 @@ parse_probe_arg(char *arg, const struct fetch_type *type,
> code->op = FETCH_OP_IMM;
> }
> break;
> + case '(':
> + ret = handle_typecast(arg, pcode, end, ctx);
> + break;
> default:
> if (isalpha(arg[0]) || arg[0] == '_') { /* BTF variable */
> if (!tparg_is_function_entry(ctx->flags) &&
> diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
> index 262d8707a3df..952e3d7582b8 100644
> --- a/kernel/trace/trace_probe.h
> +++ b/kernel/trace/trace_probe.h
> @@ -394,6 +394,7 @@ static inline int traceprobe_get_entry_data_size(struct trace_probe *tp)
> * TPARG_FL_KERNEL and TPARG_FL_USER are also mutually exclusive.
> * TPARG_FL_FPROBE and TPARG_FL_TPOINT are optional but it should be with
> * TPARG_FL_KERNEL.
> + * TPARG_FL_TYPECAST is set if an argument was typecast to a structure.
> */
> #define TPARG_FL_RETURN BIT(0)
> #define TPARG_FL_KERNEL BIT(1)
> @@ -402,6 +403,7 @@ static inline int traceprobe_get_entry_data_size(struct trace_probe *tp)
> #define TPARG_FL_USER BIT(4)
> #define TPARG_FL_FPROBE BIT(5)
> #define TPARG_FL_TPOINT BIT(6)
> +#define TPARG_FL_TYPECAST BIT(7)
> #define TPARG_FL_LOC_MASK GENMASK(4, 0)
>
> static inline bool tparg_is_function_entry(unsigned int flags)
> @@ -422,7 +424,9 @@ struct traceprobe_parse_context {
> const struct btf_param *params; /* Parameter of the function */
> s32 nr_params; /* The number of the parameters */
> struct btf *btf; /* The BTF to be used */
> + struct btf *struct_btf; /* The BTF to be used for structs */
> const struct btf_type *last_type; /* Saved type */
> + const struct btf_type *last_struct; /* Saved structure */
> u32 last_bitoffs; /* Saved bitoffs */
> u32 last_bitsize; /* Saved bitsize */
> struct trace_probe *tp;
> @@ -563,7 +567,8 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call,
> C(NEED_STRING_TYPE, "$comm and immediate-string only accepts string type"),\
> C(TOO_MANY_ARGS, "Too many arguments are specified"), \
> C(TOO_MANY_EARGS, "Too many entry arguments specified"), \
> - C(EVENT_TOO_BIG, "Event too big (too many fields?)"),
> + C(EVENT_TOO_BIG, "Event too big (too many fields?)"), \
> + C(TYPECAST_NOT_EVENT, "Typecasts are only for eprobe fields"),
>
> #undef C
> #define C(a, b) TP_ERR_##a
> --
> 2.53.0
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply
* Re: [PATCH] tracing/probes: Point the error offset correctly for eprobe argument error
From: Masami Hiramatsu @ 2026-05-30 13:46 UTC (permalink / raw)
To: Steven Rostedt
Cc: Shuah Khan, Mathieu Desnoyers, linux-kernel, linux-trace-kernel,
linux-kselftest
In-Reply-To: <20260528222934.7d0b1881@fedora>
On Thu, 28 May 2026 22:29:34 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Mon, 25 May 2026 11:21:14 +0900
> "Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
>
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> >
> > Fix to point the error offset correctly for eprobe argument error.
> > In the cleanup commit 1b8b0cd754cd ("tracing/probes: Move event parameter
> > fetching code to common parser"), due to incorrect backward compatibility
> > aimed at conforming to the test specifications, the error location was set
> > to 0 when a non-existent formal parameter was specified for Eprobe.
> > However, this should be corrected in both the test and the implementation
> > to point correct error position.
> >
> > Fixes: 1b8b0cd754cd ("tracing/probes: Move event parameter fetching code to common parser")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
>
> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
>
Thanks! Let me pick this to probes/fixes branch.
> -- Steve
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
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