From: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
To: andrew.cooper3@citrix.com, hjl.tools@gmail.com,
joao@overdrivepizza.com, jpoimboe@redhat.com,
Peter Zijlstra <peterz@infradead.org>,
x86@kernel.org
Cc: alexei.starovoitov@gmail.com, alyssa.milburn@intel.com,
keescook@chromium.org, linux-kernel@vger.kernel.org,
mark.rutland@arm.com, mbenes@suse.cz, mhiramat@kernel.org,
ndesaulniers@google.com, rostedt@goodmis.org,
samitolvanen@google.com
Subject: Re: [PATCH v2 12/39] x86/ibt,ftrace: Search for __fentry__ location
Date: Wed, 02 Mar 2022 21:55:58 +0530 [thread overview]
Message-ID: <1646238087.afjf09xr2j.naveen@linux.ibm.com> (raw)
In-Reply-To: <20220224151322.714815604@infradead.org>
Peter Zijlstra wrote:
> Have ftrace_location() search the symbol for the __fentry__ location
> when it isn't at func+0 and use this for {,un}register_ftrace_direct().
>
> This avoids a whole bunch of assumptions about __fentry__ being at
> func+0.
>
> Suggested-by: Steven Rostedt <rostedt@goodmis.org>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> kernel/trace/ftrace.c | 30 ++++++++++++++++++++++++++++--
> 1 file changed, 28 insertions(+), 2 deletions(-)
>
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -1578,7 +1578,24 @@ unsigned long ftrace_location_range(unsi
> */
> unsigned long ftrace_location(unsigned long ip)
> {
> - return ftrace_location_range(ip, ip);
> + struct dyn_ftrace *rec;
> + unsigned long offset;
> + unsigned long size;
> +
> + rec = lookup_rec(ip, ip);
> + if (!rec) {
> + if (!kallsyms_lookup_size_offset(ip, &size, &offset))
> + goto out;
> +
> + if (!offset)
> + rec = lookup_rec(ip - offset, (ip - offset) + size);
> + }
> +
> + if (rec)
> + return rec->ip;
> +
> +out:
> + return 0;
> }
>
> /**
> @@ -5110,11 +5127,16 @@ int register_ftrace_direct(unsigned long
> struct ftrace_func_entry *entry;
> struct ftrace_hash *free_hash = NULL;
> struct dyn_ftrace *rec;
> - int ret = -EBUSY;
> + int ret = -ENODEV;
>
> mutex_lock(&direct_mutex);
>
> + ip = ftrace_location(ip);
> + if (!ip)
> + goto out_unlock;
> +
> /* See if there's a direct function at @ip already */
> + ret = -EBUSY;
> if (ftrace_find_rec_direct(ip))
> goto out_unlock;
I think some of the validation at this point can be removed (diff below).
>
> @@ -5222,6 +5244,10 @@ int unregister_ftrace_direct(unsigned lo
>
> mutex_lock(&direct_mutex);
>
> + ip = ftrace_location(ip);
> + if (!ip)
> + goto out_unlock;
> +
> entry = find_direct_entry(&ip, NULL);
> if (!entry)
> goto out_unlock;
We should also update modify_ftrace_direct(). An incremental diff below.
- Naveen
---
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 65d7553668ca3d..17ce4751a2051a 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5126,7 +5126,6 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
struct ftrace_direct_func *direct;
struct ftrace_func_entry *entry;
struct ftrace_hash *free_hash = NULL;
- struct dyn_ftrace *rec;
int ret = -ENODEV;
mutex_lock(&direct_mutex);
@@ -5140,26 +5139,6 @@ int register_ftrace_direct(unsigned long ip, unsigned long addr)
if (ftrace_find_rec_direct(ip))
goto out_unlock;
- ret = -ENODEV;
- rec = lookup_rec(ip, ip);
- if (!rec)
- goto out_unlock;
-
- /*
- * Check if the rec says it has a direct call but we didn't
- * find one earlier?
- */
- if (WARN_ON(rec->flags & FTRACE_FL_DIRECT))
- goto out_unlock;
-
- /* Make sure the ip points to the exact record */
- if (ip != rec->ip) {
- ip = rec->ip;
- /* Need to check this ip for a direct. */
- if (ftrace_find_rec_direct(ip))
- goto out_unlock;
- }
-
ret = -ENOMEM;
direct = ftrace_find_direct_func(addr);
if (!direct) {
@@ -5380,6 +5359,10 @@ int modify_ftrace_direct(unsigned long ip,
mutex_lock(&direct_mutex);
mutex_lock(&ftrace_lock);
+ ip = ftrace_location(ip);
+ if (!ip)
+ goto out_unlock;
+
entry = find_direct_entry(&ip, &rec);
if (!entry)
goto out_unlock;
--
2.35.1
next prev parent reply other threads:[~2022-03-02 16:26 UTC|newest]
Thread overview: 183+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-24 14:51 [PATCH v2 00/39] x86: Kernel IBT Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 01/39] kbuild: Fix clang build Peter Zijlstra
2022-02-25 0:11 ` Kees Cook
2022-03-01 21:16 ` Nick Desaulniers
2022-03-02 0:47 ` Kees Cook
2022-03-02 0:53 ` Fangrui Song
2022-03-02 16:37 ` Nathan Chancellor
2022-03-02 18:40 ` Kees Cook
2022-03-02 19:18 ` Nick Desaulniers
2022-03-02 21:15 ` Nathan Chancellor
2022-03-02 22:07 ` Nick Desaulniers
2022-03-02 23:00 ` Kees Cook
2022-03-02 23:10 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 02/39] static_call: Avoid building empty .static_call_sites Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 03/39] x86/module: Fix the paravirt vs alternative order Peter Zijlstra
2022-03-01 14:37 ` Miroslav Benes
2022-02-24 14:51 ` [PATCH v2 04/39] objtool: Add --dry-run Peter Zijlstra
2022-02-25 0:27 ` Kees Cook
2022-03-01 14:37 ` Miroslav Benes
2022-02-24 14:51 ` [PATCH v2 05/39] x86: Base IBT bits Peter Zijlstra
2022-02-25 0:35 ` Kees Cook
2022-02-25 0:46 ` Nathan Chancellor
2022-02-25 22:08 ` Nathan Chancellor
2022-02-26 0:29 ` Joao Moreira
2022-02-26 4:58 ` Kees Cook
2022-02-26 4:59 ` Fāng-ruì Sòng
2022-02-26 5:04 ` Kees Cook
2022-02-25 13:41 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 06/39] x86/ibt: Add ANNOTATE_NOENDBR Peter Zijlstra
2022-02-25 0:36 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 07/39] x86/entry: Sprinkle ENDBR dust Peter Zijlstra
2022-02-24 22:37 ` Josh Poimboeuf
2022-02-25 0:42 ` Kees Cook
2022-02-25 9:22 ` Andrew Cooper
2022-02-24 14:51 ` [PATCH v2 08/39] x86/linkage: Add ENDBR to SYM_FUNC_START*() Peter Zijlstra
2022-02-25 0:45 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 09/39] x86/ibt,paravirt: Sprinkle ENDBR Peter Zijlstra
2022-02-25 0:47 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 10/39] x86/ibt,crypto: Add ENDBR for the jump-table entries Peter Zijlstra
2022-02-24 22:41 ` Josh Poimboeuf
2022-02-25 0:50 ` Kees Cook
2022-02-25 10:22 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 11/39] x86/ibt,kvm: Add ENDBR to fastops Peter Zijlstra
2022-02-25 0:54 ` Kees Cook
2022-02-25 10:24 ` Peter Zijlstra
2022-02-25 13:09 ` David Laight
2022-02-24 14:51 ` [PATCH v2 12/39] x86/ibt,ftrace: Search for __fentry__ location Peter Zijlstra
2022-02-24 15:55 ` Masami Hiramatsu
2022-02-24 15:58 ` Steven Rostedt
2022-02-24 15:59 ` Steven Rostedt
2022-02-24 16:01 ` Steven Rostedt
2022-02-24 22:46 ` Josh Poimboeuf
2022-02-24 22:51 ` Steven Rostedt
2022-02-25 1:34 ` Masami Hiramatsu
2022-02-25 2:19 ` Steven Rostedt
2022-02-25 10:20 ` Masami Hiramatsu
2022-02-25 13:36 ` Steven Rostedt
2022-03-01 18:57 ` Naveen N. Rao
2022-03-01 19:20 ` Steven Rostedt
2022-03-02 13:20 ` Peter Zijlstra
2022-03-02 16:01 ` Steven Rostedt
2022-03-02 19:47 ` Steven Rostedt
2022-03-02 20:48 ` Steven Rostedt
2022-03-02 20:51 ` Peter Zijlstra
2022-03-03 9:45 ` Naveen N. Rao
2022-03-03 13:04 ` Peter Zijlstra
2022-03-03 14:34 ` Steven Rostedt
2022-03-03 15:59 ` Peter Zijlstra
2022-03-06 3:48 ` Masami Hiramatsu
2022-03-09 11:47 ` Naveen N. Rao
2022-03-03 14:39 ` Naveen N. Rao
2022-02-25 0:55 ` Kees Cook
2022-03-02 16:25 ` Naveen N. Rao [this message]
2022-02-24 14:51 ` [PATCH v2 13/39] x86/livepatch: Validate " Peter Zijlstra
2022-02-24 23:02 ` Josh Poimboeuf
2022-02-24 14:51 ` [PATCH v2 14/39] x86/ibt,ftrace: Make function-graph play nice Peter Zijlstra
2022-02-24 15:36 ` Peter Zijlstra
2022-02-24 15:42 ` Steven Rostedt
2022-02-24 23:09 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 15/39] x86/ibt,kprobes: Fix more +0 assumptions Peter Zijlstra
2022-02-25 0:58 ` Kees Cook
2022-02-25 1:32 ` Masami Hiramatsu
2022-02-25 10:46 ` Peter Zijlstra
2022-02-25 13:42 ` Masami Hiramatsu
2022-02-25 15:41 ` Peter Zijlstra
2022-02-26 2:10 ` Masami Hiramatsu
2022-02-26 11:48 ` Peter Zijlstra
2022-02-25 14:14 ` Steven Rostedt
2022-02-26 7:09 ` Masami Hiramatsu
2022-02-28 6:07 ` Masami Hiramatsu
2022-02-28 23:25 ` Peter Zijlstra
2022-03-01 2:49 ` Masami Hiramatsu
2022-03-01 8:28 ` Peter Zijlstra
2022-03-01 17:19 ` Naveen N. Rao
2022-03-01 19:12 ` Peter Zijlstra
2022-03-01 20:05 ` Peter Zijlstra
2022-03-02 15:59 ` Naveen N. Rao
2022-03-02 16:38 ` Peter Zijlstra
2022-03-02 16:17 ` Naveen N. Rao
2022-03-02 19:32 ` Peter Zijlstra
2022-03-02 19:39 ` Peter Zijlstra
2022-03-03 12:11 ` Naveen N. Rao
2022-03-03 1:54 ` Masami Hiramatsu
2022-03-02 0:11 ` Masami Hiramatsu
2022-03-02 10:25 ` Peter Zijlstra
2022-03-01 17:03 ` Naveen N. Rao
2022-02-24 14:51 ` [PATCH v2 16/39] x86/bpf: Add ENDBR instructions to prologue and trampoline Peter Zijlstra
2022-02-24 23:37 ` Josh Poimboeuf
2022-02-25 0:59 ` Kees Cook
2022-02-25 11:20 ` Peter Zijlstra
2022-02-25 12:24 ` Peter Zijlstra
2022-02-25 22:46 ` Josh Poimboeuf
2022-02-24 14:51 ` [PATCH v2 17/39] x86/ibt,ftrace: Add ENDBR to samples/ftrace Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 18/39] x86/ibt: Add IBT feature, MSR and #CP handling Peter Zijlstra
2022-02-24 23:55 ` Josh Poimboeuf
2022-02-25 10:51 ` Peter Zijlstra
2022-02-25 11:10 ` Peter Zijlstra
2022-02-25 23:51 ` Josh Poimboeuf
2022-02-26 11:55 ` Peter Zijlstra
2022-02-25 1:09 ` Kees Cook
2022-02-25 19:59 ` Edgecombe, Rick P
2022-03-01 15:14 ` Peter Zijlstra
2022-03-01 21:02 ` Peter Zijlstra
2022-03-01 23:13 ` Josh Poimboeuf
2022-03-02 1:59 ` Edgecombe, Rick P
2022-03-02 13:49 ` Peter Zijlstra
2022-03-02 18:38 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 19/39] x86: Disable IBT around firmware Peter Zijlstra
2022-02-25 1:10 ` Kees Cook
2022-02-24 14:51 ` [PATCH v2 20/39] x86/bugs: Disable Retpoline when IBT Peter Zijlstra
2022-02-25 1:11 ` Kees Cook
2022-02-25 2:22 ` Josh Poimboeuf
2022-02-25 10:55 ` Peter Zijlstra
2022-02-24 14:51 ` [PATCH v2 21/39] x86/ibt: Annotate text references Peter Zijlstra
2022-02-25 0:47 ` Josh Poimboeuf
2022-02-25 12:57 ` Peter Zijlstra
2022-02-25 13:04 ` Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 22/39] x86/ibt,ftrace: Annotate ftrace code patching Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 23/39] x86/ibt,sev: Annotations Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 24/39] x86/text-patching: Make text_gen_insn() IBT aware Peter Zijlstra
2022-02-25 0:49 ` Josh Poimboeuf
2022-02-24 14:52 ` [PATCH v2 25/39] x86/ibt,paravirt: Use text_gen_insn() for paravirt_patch() Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 26/39] x86/entry: Cleanup PARAVIRT Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 27/39] x86/entry,xen: Early rewrite of restore_regs_and_return_to_kernel() Peter Zijlstra
2022-02-24 17:51 ` Andrew Cooper
2022-02-24 14:52 ` [PATCH v2 28/39] x86/ibt,xen: Sprinkle the ENDBR Peter Zijlstra
2022-02-25 0:54 ` Josh Poimboeuf
2022-02-25 13:16 ` Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 29/39] objtool: Rename --duplicate to --lto Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 30/39] Kbuild: Allow whole module objtool runs Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 31/39] objtool: Read the NOENDBR annotation Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 32/39] x86/ibt: Dont generate ENDBR in .discard.text Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 33/39] objtool: Add IBT/ENDBR decoding Peter Zijlstra
2022-03-03 10:53 ` Miroslav Benes
2022-03-03 11:06 ` Andrew Cooper
2022-03-03 12:33 ` Miroslav Benes
2022-03-03 14:13 ` Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 34/39] objtool: Validate IBT assumptions Peter Zijlstra
2022-02-27 3:13 ` Josh Poimboeuf
2022-02-27 17:00 ` Peter Zijlstra
2022-02-27 22:20 ` Josh Poimboeuf
2022-02-28 9:47 ` Peter Zijlstra
2022-02-28 18:36 ` Josh Poimboeuf
2022-02-28 20:10 ` Peter Zijlstra
2022-02-28 9:26 ` Peter Zijlstra
2022-02-28 18:39 ` Josh Poimboeuf
2022-02-24 14:52 ` [PATCH v2 35/39] objtool: IBT fix direct JMP/CALL Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 36/39] objtool: Find unused ENDBR instructions Peter Zijlstra
2022-02-27 3:46 ` Josh Poimboeuf
2022-02-28 12:41 ` Peter Zijlstra
2022-02-28 17:36 ` Josh Poimboeuf
2022-02-24 14:52 ` [PATCH v2 37/39] x86/ibt: Finish --ibt-fix-direct on module loading Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 38/39] x86/ibt: Ensure module init/exit points have references Peter Zijlstra
2022-02-24 14:52 ` [PATCH v2 39/39] x86/alternative: Use .ibt_endbr_sites to seal indirect calls Peter Zijlstra
2022-02-24 20:26 ` [PATCH v2 00/39] x86: Kernel IBT Josh Poimboeuf
2022-02-25 15:28 ` Peter Zijlstra
2022-02-25 15:43 ` Peter Zijlstra
2022-02-25 17:26 ` Josh Poimboeuf
2022-02-25 17:32 ` Steven Rostedt
2022-02-25 19:53 ` Peter Zijlstra
2022-02-25 20:15 ` Josh Poimboeuf
2022-03-01 23:10 ` Josh Poimboeuf
2022-03-02 10:20 ` Peter Zijlstra
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