From patchwork Sat Oct 26 15:46:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 13852269 Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECCCC43172; Sat, 26 Oct 2024 15:48:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=167.114.26.122 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729957697; cv=none; b=c3AUEUnwTpefhLiIVPwuBqEClqioKeWBF2q523QhJBip7CIVZ6LByJjoBcF1unlEARPBHd6qaSD/oixveCAxJz6tOmjguA7xojrssCoqsqNgAIQ4BGsEgoATs3hj4cz2aJLfnEAVX38fyTDrCytfTVRtEK7WD67e8/Iz/TdYk1g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729957697; c=relaxed/simple; bh=Vl+dJW1dLHWdx44iF4qkzr4xppHjV8IF1v86QpLfsa4=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=gZItsgDjfG3U7A1k1WDiQn3idU5zqUAcvdIMzXp5LTsFzEQ4NqwSgsxNsKZrYX29WPnvrxSLFbf3LEoc2UbjGSJ8SlZBTBS9tWe2qnQkKzW1F1CdSju1rtfYEfCgwsMVRrJomavdV+HoomH7aKW1yUa2HIfcu/OBh4Tnww3aF6g= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com; spf=pass smtp.mailfrom=efficios.com; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b=UDw/7g5J; arc=none smtp.client-ip=167.114.26.122 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=efficios.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=efficios.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="UDw/7g5J" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=efficios.com; s=smtpout1; t=1729957693; bh=Vl+dJW1dLHWdx44iF4qkzr4xppHjV8IF1v86QpLfsa4=; h=From:To:Cc:Subject:Date:From; b=UDw/7g5JRM29IrEBMBWTtNEvMR2N6TuaMJTHSxl/e45Xq3Pe94NjAO/AsThf3pHVs 8BfzA7eDMqfcTg+SVY1PG46AOA3qVLinemQsx4SQY3wehA3NI/VqiMpUBWN4WNVfn4 WvqupopNOqXNAc6g5PwGm/7QwMjo207ck6TYBj6pjb4GwVQaiUiy2HZ6X6EskEgEpg ErpL0E6zfwFD4tUiTkfxb07r1crirH8SyhHSuOTg6pGqNsM1Sy6Pcyz1S2x0rz+bRG d41xzZG5u74vBWUGcMpP/F/mL/0403qMbXU9v3nE+CVaA51btUD7nrbubxP36eevhV C0MdpuNiNnmUw== Received: from thinkos.internal.efficios.com (unknown [IPv6:2606:6d00:100:4000:cacb:9855:de1f:ded2]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4XbPF949CJzNmM; Sat, 26 Oct 2024 11:48:13 -0400 (EDT) From: Mathieu Desnoyers To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Michael Jeanson , Masami Hiramatsu , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E . McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , Jordan Rife Subject: [RFC PATCH v3 1/3] tracing: Introduce tracepoint extended structure Date: Sat, 26 Oct 2024 11:46:27 -0400 Message-Id: <20241026154629.593041-1-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-State: RFC Shrink the struct tracepoint size from 80 bytes to 72 bytes on x86-64 by moving the (typically NULL) regfunc/unregfunc pointers to an extended structure. Signed-off-by: Mathieu Desnoyers Cc: Michael Jeanson Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Yonghong Song Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Joel Fernandes Cc: Jordan Rife --- include/linux/tracepoint-defs.h | 8 ++++++-- include/linux/tracepoint.h | 19 +++++++++++++------ kernel/tracepoint.c | 9 ++++----- 3 files changed, 23 insertions(+), 13 deletions(-) diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h index 60a6e8314d4c..967c08d9da84 100644 --- a/include/linux/tracepoint-defs.h +++ b/include/linux/tracepoint-defs.h @@ -29,6 +29,11 @@ struct tracepoint_func { int prio; }; +struct tracepoint_ext { + int (*regfunc)(void); + void (*unregfunc)(void); +}; + struct tracepoint { const char *name; /* Tracepoint name */ struct static_key_false key; @@ -36,9 +41,8 @@ struct tracepoint { void *static_call_tramp; void *iterator; void *probestub; - int (*regfunc)(void); - void (*unregfunc)(void); struct tracepoint_func __rcu *funcs; + struct tracepoint_ext *ext; }; #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 0dc67fad706c..83dc24ee8b13 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -302,7 +302,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) * structures, so we create an array of pointers that will be used for iteration * on the tracepoints. */ -#define DEFINE_TRACE_FN(_name, _reg, _unreg, proto, args) \ +#define __DEFINE_TRACE_EXT(_name, _ext, proto, args) \ static const char __tpstrtab_##_name[] \ __section("__tracepoints_strings") = #_name; \ extern struct static_call_key STATIC_CALL_KEY(tp_func_##_name); \ @@ -316,9 +316,9 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) .static_call_tramp = STATIC_CALL_TRAMP_ADDR(tp_func_##_name), \ .iterator = &__traceiter_##_name, \ .probestub = &__probestub_##_name, \ - .regfunc = _reg, \ - .unregfunc = _unreg, \ - .funcs = NULL }; \ + .funcs = NULL, \ + .ext = _ext, \ + }; \ __TRACEPOINT_ENTRY(_name); \ int __traceiter_##_name(void *__data, proto) \ { \ @@ -341,8 +341,15 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) } \ DEFINE_STATIC_CALL(tp_func_##_name, __traceiter_##_name); -#define DEFINE_TRACE(name, proto, args) \ - DEFINE_TRACE_FN(name, NULL, NULL, PARAMS(proto), PARAMS(args)); +#define DEFINE_TRACE_FN(_name, _reg, _unreg, _proto, _args) \ + struct tracepoint_ext __tracepoint_ext_##_name = { \ + .regfunc = _reg, \ + .unregfunc = _unreg, \ + }; \ + __DEFINE_TRACE_EXT(_name, &__tracepoint_ext_##_name, PARAMS(_proto), PARAMS(_args)); + +#define DEFINE_TRACE(_name, _proto, _args) \ + __DEFINE_TRACE_EXT(_name, NULL, PARAMS(_proto), PARAMS(_args)); #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) \ EXPORT_SYMBOL_GPL(__tracepoint_##name); \ diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 6474e2cf22c9..5658dc92f5b5 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -278,8 +278,8 @@ static int tracepoint_add_func(struct tracepoint *tp, struct tracepoint_func *old, *tp_funcs; int ret; - if (tp->regfunc && !static_key_enabled(&tp->key)) { - ret = tp->regfunc(); + if (tp->ext && tp->ext->regfunc && !static_key_enabled(&tp->key)) { + ret = tp->ext->regfunc(); if (ret < 0) return ret; } @@ -362,9 +362,8 @@ static int tracepoint_remove_func(struct tracepoint *tp, switch (nr_func_state(tp_funcs)) { case TP_FUNC_0: /* 1->0 */ /* Removed last function */ - if (tp->unregfunc && static_key_enabled(&tp->key)) - tp->unregfunc(); - + if (tp->ext && tp->ext->unregfunc && static_key_enabled(&tp->key)) + tp->ext->unregfunc(); static_branch_disable(&tp->key); /* Set iterator static call */ tracepoint_update_call(tp, tp_funcs); From patchwork Sat Oct 26 15:46:28 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 13852268 Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ECC8C7EEFD; 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Sat, 26 Oct 2024 11:48:13 -0400 (EDT) From: Mathieu Desnoyers To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Michael Jeanson , Masami Hiramatsu , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E . McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , Jordan Rife Subject: [RFC PATCH v3 2/3] tracing: Introduce tracepoint_is_syscall() Date: Sat, 26 Oct 2024 11:46:28 -0400 Message-Id: <20241026154629.593041-2-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241026154629.593041-1-mathieu.desnoyers@efficios.com> References: <20241026154629.593041-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-State: RFC Introduce a "syscall" flag within the extended structure to know whether a tracepoint needs rcu tasks trace grace period before reclaim. This can be queried using tracepoint_is_syscall(). Signed-off-by: Mathieu Desnoyers Cc: Michael Jeanson Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Yonghong Song Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Joel Fernandes Cc: Jordan Rife --- include/linux/tracepoint-defs.h | 2 ++ include/linux/tracepoint.h | 24 ++++++++++++++++++++++++ include/trace/define_trace.h | 2 +- 3 files changed, 27 insertions(+), 1 deletion(-) diff --git a/include/linux/tracepoint-defs.h b/include/linux/tracepoint-defs.h index 967c08d9da84..53119e074c87 100644 --- a/include/linux/tracepoint-defs.h +++ b/include/linux/tracepoint-defs.h @@ -32,6 +32,8 @@ struct tracepoint_func { struct tracepoint_ext { int (*regfunc)(void); void (*unregfunc)(void); + /* Flags. */ + unsigned int syscall:1; }; struct tracepoint { diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h index 83dc24ee8b13..93e70bc64533 100644 --- a/include/linux/tracepoint.h +++ b/include/linux/tracepoint.h @@ -104,6 +104,12 @@ void for_each_tracepoint_in_module(struct module *mod, * tracepoint_synchronize_unregister must be called between the last tracepoint * probe unregistration and the end of module exit to make sure there is no * caller executing a probe when it is freed. + * + * An alternative is to use the following for batch reclaim associated + * with a given tracepoint: + * + * - tracepoint_is_syscall() == false: call_rcu() + * - tracepoint_is_syscall() == true: call_rcu_tasks_trace() */ #ifdef CONFIG_TRACEPOINTS static inline void tracepoint_synchronize_unregister(void) @@ -111,9 +117,17 @@ static inline void tracepoint_synchronize_unregister(void) synchronize_rcu_tasks_trace(); synchronize_rcu(); } +static inline bool tracepoint_is_syscall(struct tracepoint *tp) +{ + return tp->ext && tp->ext->syscall; +} #else static inline void tracepoint_synchronize_unregister(void) { } +static inline bool tracepoint_is_syscall(struct tracepoint *tp) +{ + return false; +} #endif #ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS @@ -345,6 +359,15 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) struct tracepoint_ext __tracepoint_ext_##_name = { \ .regfunc = _reg, \ .unregfunc = _unreg, \ + .syscall = false, \ + }; \ + __DEFINE_TRACE_EXT(_name, &__tracepoint_ext_##_name, PARAMS(_proto), PARAMS(_args)); + +#define DEFINE_TRACE_SYSCALL(_name, _reg, _unreg, _proto, _args) \ + struct tracepoint_ext __tracepoint_ext_##_name = { \ + .regfunc = _reg, \ + .unregfunc = _unreg, \ + .syscall = true, \ }; \ __DEFINE_TRACE_EXT(_name, &__tracepoint_ext_##_name, PARAMS(_proto), PARAMS(_args)); @@ -389,6 +412,7 @@ static inline struct tracepoint *tracepoint_ptr_deref(tracepoint_ptr_t *p) #define __DECLARE_TRACE_SYSCALL __DECLARE_TRACE #define DEFINE_TRACE_FN(name, reg, unreg, proto, args) +#define DEFINE_TRACE_SYSCALL(name, reg, unreg, proto, args) #define DEFINE_TRACE(name, proto, args) #define EXPORT_TRACEPOINT_SYMBOL_GPL(name) #define EXPORT_TRACEPOINT_SYMBOL(name) diff --git a/include/trace/define_trace.h b/include/trace/define_trace.h index ff5fa17a6259..63fea2218afa 100644 --- a/include/trace/define_trace.h +++ b/include/trace/define_trace.h @@ -48,7 +48,7 @@ #undef TRACE_EVENT_SYSCALL #define TRACE_EVENT_SYSCALL(name, proto, args, struct, assign, print, reg, unreg) \ - DEFINE_TRACE_FN(name, reg, unreg, PARAMS(proto), PARAMS(args)) + DEFINE_TRACE_SYSCALL(name, reg, unreg, PARAMS(proto), PARAMS(args)) #undef TRACE_EVENT_NOP #define TRACE_EVENT_NOP(name, proto, args, struct, assign, print) From patchwork Sat Oct 26 15:46:29 2024 Content-Type: text/plain; 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Sat, 26 Oct 2024 11:48:14 -0400 (EDT) From: Mathieu Desnoyers To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers , Michael Jeanson , Masami Hiramatsu , Peter Zijlstra , Alexei Starovoitov , Yonghong Song , "Paul E . McKenney" , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Namhyung Kim , Andrii Nakryiko , bpf@vger.kernel.org, Joel Fernandes , Jordan Rife , syzbot+b390c8062d8387b6272a@syzkaller.appspotmail.com Subject: [RFC PATCH v3 3/3] tracing: Fix syscall tracepoint use-after-free Date: Sat, 26 Oct 2024 11:46:29 -0400 Message-Id: <20241026154629.593041-3-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20241026154629.593041-1-mathieu.desnoyers@efficios.com> References: <20241026154629.593041-1-mathieu.desnoyers@efficios.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-State: RFC The grace period used internally within tracepoint.c:release_probes() uses call_rcu() to batch waiting for quiescence of old probe arrays, rather than using the tracepoint_synchronize_unregister() which blocks while waiting for quiescence. With the introduction of faultable syscall tracepoints, this causes use-after-free issues reproduced with syzkaller. Fix this by using the appropriate call_rcu() or call_rcu_tasks_trace() before invoking the rcu_free_old_probes callback. This can be chosen using the tracepoint_is_syscall() API. A similar issue exists in bpf use of call_rcu(). Fixing this is left to a separate change. Reported-by: syzbot+b390c8062d8387b6272a@syzkaller.appspotmail.com Fixes: a363d27cdbc2 ("tracing: Allow system call tracepoints to handle page faults") Signed-off-by: Mathieu Desnoyers Cc: Michael Jeanson Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Peter Zijlstra Cc: Alexei Starovoitov Cc: Yonghong Song Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo Cc: Mark Rutland Cc: Alexander Shishkin Cc: Namhyung Kim Cc: Andrii Nakryiko Cc: bpf@vger.kernel.org Cc: Joel Fernandes Cc: Jordan Rife --- Changes since v0: - Introduce tracepoint_call_rcu(), - Fix bpf_link_free() use of call_rcu as well. Changes since v1: - Use tracepoint_call_rcu() for bpf_prog_put as well. Changes since v2: - Do not cover bpf changes in the same commit, let bpf developers implement it. --- kernel/tracepoint.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c index 5658dc92f5b5..47569fb06596 100644 --- a/kernel/tracepoint.c +++ b/kernel/tracepoint.c @@ -106,13 +106,16 @@ static void rcu_free_old_probes(struct rcu_head *head) kfree(container_of(head, struct tp_probes, rcu)); } -static inline void release_probes(struct tracepoint_func *old) +static inline void release_probes(struct tracepoint *tp, struct tracepoint_func *old) { if (old) { struct tp_probes *tp_probes = container_of(old, struct tp_probes, probes[0]); - call_rcu(&tp_probes->rcu, rcu_free_old_probes); + if (tracepoint_is_syscall(tp)) + call_rcu_tasks_trace(&tp_probes->rcu, rcu_free_old_probes); + else + call_rcu(&tp_probes->rcu, rcu_free_old_probes); } } @@ -334,7 +337,7 @@ static int tracepoint_add_func(struct tracepoint *tp, break; } - release_probes(old); + release_probes(tp, old); return 0; } @@ -405,7 +408,7 @@ static int tracepoint_remove_func(struct tracepoint *tp, WARN_ON_ONCE(1); break; } - release_probes(old); + release_probes(tp, old); return 0; }