From 6743ad432ec92e680cd0d9db86cb17b949cf5a43 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 12 May 2020 17:02:33 +0900 Subject: kprobes: Suppress the suspicious RCU warning on kprobes Anders reported that the lockdep warns that suspicious RCU list usage in register_kprobe() (detected by CONFIG_PROVE_RCU_LIST.) This is because get_kprobe() access kprobe_table[] by hlist_for_each_entry_rcu() without rcu_read_lock. If we call get_kprobe() from the breakpoint handler context, it is run with preempt disabled, so this is not a problem. But in other cases, instead of rcu_read_lock(), we locks kprobe_mutex so that the kprobe_table[] is not updated. So, current code is safe, but still not good from the view point of RCU. Joel suggested that we can silent that warning by passing lockdep_is_held() to the last argument of hlist_for_each_entry_rcu(). Add lockdep_is_held(&kprobe_mutex) at the end of the hlist_for_each_entry_rcu() to suppress the warning. Link: http://lkml.kernel.org/r/158927055350.27680.10261450713467997503.stgit@devnote2 Reported-by: Anders Roxell Suggested-by: Joel Fernandes Reviewed-by: Joel Fernandes (Google) Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/kprobes.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 50cd84f53df0..8b2fd4145ab3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -326,7 +326,8 @@ struct kprobe *get_kprobe(void *addr) struct kprobe *p; head = &kprobe_table[hash_ptr(addr, KPROBE_HASH_BITS)]; - hlist_for_each_entry_rcu(p, head, hlist) { + hlist_for_each_entry_rcu(p, head, hlist, + lockdep_is_held(&kprobe_mutex)) { if (p->addr == addr) return p; } -- cgit From 7e6a71d8e60187726e29b13d9e9b23b77026c17a Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 12 May 2020 17:02:44 +0900 Subject: kprobes: Use non RCU traversal APIs on kprobe_tables if possible Current kprobes uses RCU traversal APIs on kprobe_tables even if it is safe because kprobe_mutex is locked. Make those traversals to non-RCU APIs where the kprobe_mutex is locked. Link: http://lkml.kernel.org/r/158927056452.27680.9710575332163005121.stgit@devnote2 Reviewed-by: Joel Fernandes (Google) Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/kprobes.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 8b2fd4145ab3..ceb0e273bd69 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -46,6 +46,11 @@ static int kprobes_initialized; +/* kprobe_table can be accessed by + * - Normal hlist traversal and RCU add/del under kprobe_mutex is held. + * Or + * - RCU hlist traversal under disabling preempt (breakpoint handlers) + */ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; @@ -850,7 +855,7 @@ static void optimize_all_kprobes(void) kprobes_allow_optimization = true; for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; - hlist_for_each_entry_rcu(p, head, hlist) + hlist_for_each_entry(p, head, hlist) if (!kprobe_disabled(p)) optimize_kprobe(p); } @@ -877,7 +882,7 @@ static void unoptimize_all_kprobes(void) kprobes_allow_optimization = false; for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; - hlist_for_each_entry_rcu(p, head, hlist) { + hlist_for_each_entry(p, head, hlist) { if (!kprobe_disabled(p)) unoptimize_kprobe(p, false); } @@ -1500,12 +1505,14 @@ static struct kprobe *__get_valid_kprobe(struct kprobe *p) { struct kprobe *ap, *list_p; + lockdep_assert_held(&kprobe_mutex); + ap = get_kprobe(p->addr); if (unlikely(!ap)) return NULL; if (p != ap) { - list_for_each_entry_rcu(list_p, &ap->list, list) + list_for_each_entry(list_p, &ap->list, list) if (list_p == p) /* kprobe p is a valid probe */ goto valid; @@ -1670,7 +1677,9 @@ static int aggr_kprobe_disabled(struct kprobe *ap) { struct kprobe *kp; - list_for_each_entry_rcu(kp, &ap->list, list) + lockdep_assert_held(&kprobe_mutex); + + list_for_each_entry(kp, &ap->list, list) if (!kprobe_disabled(kp)) /* * There is an active probe on the list. @@ -1749,7 +1758,7 @@ static int __unregister_kprobe_top(struct kprobe *p) else { /* If disabling probe has special handlers, update aggrprobe */ if (p->post_handler && !kprobe_gone(p)) { - list_for_each_entry_rcu(list_p, &ap->list, list) { + list_for_each_entry(list_p, &ap->list, list) { if ((list_p != p) && (list_p->post_handler)) goto noclean; } @@ -2063,13 +2072,15 @@ static void kill_kprobe(struct kprobe *p) { struct kprobe *kp; + lockdep_assert_held(&kprobe_mutex); + p->flags |= KPROBE_FLAG_GONE; if (kprobe_aggrprobe(p)) { /* * If this is an aggr_kprobe, we have to list all the * chained probes and mark them GONE. */ - list_for_each_entry_rcu(kp, &p->list, list) + list_for_each_entry(kp, &p->list, list) kp->flags |= KPROBE_FLAG_GONE; p->post_handler = NULL; kill_optimized_kprobe(p); @@ -2313,7 +2324,7 @@ static int kprobes_module_callback(struct notifier_block *nb, mutex_lock(&kprobe_mutex); for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; - hlist_for_each_entry_rcu(p, head, hlist) + hlist_for_each_entry(p, head, hlist) if (within_module_init((unsigned long)p->addr, mod) || (checkcore && within_module_core((unsigned long)p->addr, mod))) { @@ -2551,7 +2562,7 @@ static int arm_all_kprobes(void) for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; /* Arm all kprobes on a best-effort basis */ - hlist_for_each_entry_rcu(p, head, hlist) { + hlist_for_each_entry(p, head, hlist) { if (!kprobe_disabled(p)) { err = arm_kprobe(p); if (err) { @@ -2594,7 +2605,7 @@ static int disarm_all_kprobes(void) for (i = 0; i < KPROBE_TABLE_SIZE; i++) { head = &kprobe_table[i]; /* Disarm all kprobes on a best-effort basis */ - hlist_for_each_entry_rcu(p, head, hlist) { + hlist_for_each_entry(p, head, hlist) { if (!arch_trampoline_kprobe(p) && !kprobe_disabled(p)) { err = disarm_kprobe(p, false); if (err) { -- cgit From 1a0aa991a6274161c95a844c58cfb801d681eb59 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 12 May 2020 17:02:56 +0900 Subject: kprobes: Fix to protect kick_kprobe_optimizer() by kprobe_mutex In kprobe_optimizer() kick_kprobe_optimizer() is called without kprobe_mutex, but this can race with other caller which is protected by kprobe_mutex. To fix that, expand kprobe_mutex protected area to protect kick_kprobe_optimizer() call. Link: http://lkml.kernel.org/r/158927057586.27680.5036330063955940456.stgit@devnote2 Fixes: cd7ebe2298ff ("kprobes: Use text_poke_smp_batch for optimizing") Cc: Ingo Molnar Cc: "Gustavo A . R . Silva" Cc: Anders Roxell Cc: "Naveen N . Rao" Cc: Anil S Keshavamurthy Cc: David Miller Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Ziqian SUN Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/kprobes.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index ceb0e273bd69..0e185763578b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -592,11 +592,12 @@ static void kprobe_optimizer(struct work_struct *work) mutex_unlock(&module_mutex); mutex_unlock(&text_mutex); cpus_read_unlock(); - mutex_unlock(&kprobe_mutex); /* Step 5: Kick optimizer again if needed */ if (!list_empty(&optimizing_list) || !list_empty(&unoptimizing_list)) kick_kprobe_optimizer(); + + mutex_unlock(&kprobe_mutex); } /* Wait for completing optimization and unoptimization */ -- cgit From 75ddf64dd276e3fc8906f27549afa229798ad916 Mon Sep 17 00:00:00 2001 From: Masami Hiramatsu Date: Tue, 12 May 2020 17:03:07 +0900 Subject: kprobes: Remove redundant arch_disarm_kprobe() call Fix to remove redundant arch_disarm_kprobe() call in force_unoptimize_kprobe(). This arch_disarm_kprobe() will be invoked if the kprobe is optimized but disabled, but that means the kprobe (optprobe) is unused (and unoptimized) state. In that case, unoptimize_kprobe() puts it in freeing_list and kprobe_optimizer (do_unoptimize_kprobes()) automatically disarm it. Thus this arch_disarm_kprobe() is redundant. Link: http://lkml.kernel.org/r/158927058719.27680.17183632908465341189.stgit@devnote2 Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware) --- kernel/kprobes.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 0e185763578b..5cb7791c16b3 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -675,8 +675,6 @@ static void force_unoptimize_kprobe(struct optimized_kprobe *op) lockdep_assert_cpus_held(); arch_unoptimize_kprobe(op); op->kp.flags &= ~KPROBE_FLAG_OPTIMIZED; - if (kprobe_disabled(&op->kp)) - arch_disarm_kprobe(&op->kp); } /* Unoptimize a kprobe if p is optimized */ -- cgit From 9b38cc704e844e41d9cf74e647bff1d249512cb3 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Tue, 12 May 2020 17:03:18 +0900 Subject: kretprobe: Prevent triggering kretprobe from within kprobe_flush_task Ziqian reported lockup when adding retprobe on _raw_spin_lock_irqsave. My test was also able to trigger lockdep output: ============================================ WARNING: possible recursive locking detected 5.6.0-rc6+ #6 Not tainted -------------------------------------------- sched-messaging/2767 is trying to acquire lock: ffffffff9a492798 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_hash_lock+0x52/0xa0 but task is already holding lock: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(kretprobe_table_locks[i].lock)); lock(&(kretprobe_table_locks[i].lock)); *** DEADLOCK *** May be due to missing lock nesting notation 1 lock held by sched-messaging/2767: #0: ffffffff9a491a18 (&(kretprobe_table_locks[i].lock)){-.-.}, at: kretprobe_trampoline+0x0/0x50 stack backtrace: CPU: 3 PID: 2767 Comm: sched-messaging Not tainted 5.6.0-rc6+ #6 Call Trace: dump_stack+0x96/0xe0 __lock_acquire.cold.57+0x173/0x2b7 ? native_queued_spin_lock_slowpath+0x42b/0x9e0 ? lockdep_hardirqs_on+0x590/0x590 ? __lock_acquire+0xf63/0x4030 lock_acquire+0x15a/0x3d0 ? kretprobe_hash_lock+0x52/0xa0 _raw_spin_lock_irqsave+0x36/0x70 ? kretprobe_hash_lock+0x52/0xa0 kretprobe_hash_lock+0x52/0xa0 trampoline_handler+0xf8/0x940 ? kprobe_fault_handler+0x380/0x380 ? find_held_lock+0x3a/0x1c0 kretprobe_trampoline+0x25/0x50 ? lock_acquired+0x392/0xbc0 ? _raw_spin_lock_irqsave+0x50/0x70 ? __get_valid_kprobe+0x1f0/0x1f0 ? _raw_spin_unlock_irqrestore+0x3b/0x40 ? finish_task_switch+0x4b9/0x6d0 ? __switch_to_asm+0x34/0x70 ? __switch_to_asm+0x40/0x70 The code within the kretprobe handler checks for probe reentrancy, so we won't trigger any _raw_spin_lock_irqsave probe in there. The problem is in outside kprobe_flush_task, where we call: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave where _raw_spin_lock_irqsave triggers the kretprobe and installs kretprobe_trampoline handler on _raw_spin_lock_irqsave return. The kretprobe_trampoline handler is then executed with already locked kretprobe_table_locks, and first thing it does is to lock kretprobe_table_locks ;-) the whole lockup path like: kprobe_flush_task kretprobe_table_lock raw_spin_lock_irqsave _raw_spin_lock_irqsave ---> probe triggered, kretprobe_trampoline installed ---> kretprobe_table_locks locked kretprobe_trampoline trampoline_handler kretprobe_hash_lock(current, &head, &flags); <--- deadlock Adding kprobe_busy_begin/end helpers that mark code with fake probe installed to prevent triggering of another kprobe within this code. Using these helpers in kprobe_flush_task, so the probe recursion protection check is hit and the probe is never set to prevent above lockup. Link: http://lkml.kernel.org/r/158927059835.27680.7011202830041561604.stgit@devnote2 Fixes: ef53d9c5e4da ("kprobes: improve kretprobe scalability with hashed locking") Cc: Ingo Molnar Cc: "Gustavo A . R . Silva" Cc: Anders Roxell Cc: "Naveen N . Rao" Cc: Anil S Keshavamurthy Cc: David Miller Cc: Ingo Molnar Cc: Peter Zijlstra Cc: stable@vger.kernel.org Reported-by: "Ziqian SUN (Zamir)" Acked-by: Masami Hiramatsu Signed-off-by: Jiri Olsa Signed-off-by: Steven Rostedt (VMware) --- kernel/kprobes.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'kernel') diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 5cb7791c16b3..4a904cc56d68 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -1241,6 +1241,26 @@ __releases(hlist_lock) } NOKPROBE_SYMBOL(kretprobe_table_unlock); +struct kprobe kprobe_busy = { + .addr = (void *) get_kprobe, +}; + +void kprobe_busy_begin(void) +{ + struct kprobe_ctlblk *kcb; + + preempt_disable(); + __this_cpu_write(current_kprobe, &kprobe_busy); + kcb = get_kprobe_ctlblk(); + kcb->kprobe_status = KPROBE_HIT_ACTIVE; +} + +void kprobe_busy_end(void) +{ + __this_cpu_write(current_kprobe, NULL); + preempt_enable(); +} + /* * This function is called from finish_task_switch when task tk becomes dead, * so that we can recycle any function-return probe instances associated @@ -1258,6 +1278,8 @@ void kprobe_flush_task(struct task_struct *tk) /* Early boot. kretprobe_table_locks not yet initialized. */ return; + kprobe_busy_begin(); + INIT_HLIST_HEAD(&empty_rp); hash = hash_ptr(tk, KPROBE_HASH_BITS); head = &kretprobe_inst_table[hash]; @@ -1271,6 +1293,8 @@ void kprobe_flush_task(struct task_struct *tk) hlist_del(&ri->hlist); kfree(ri); } + + kprobe_busy_end(); } NOKPROBE_SYMBOL(kprobe_flush_task); -- cgit From 4649079b9de1ad86be9f4c989373adb8235a8485 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (VMware)" Date: Tue, 9 Jun 2020 22:00:41 -0400 Subject: tracing: Make ftrace packed events have align of 1 When using trace-cmd on 5.6-rt for the function graph tracer, the output was corrupted. It gave output like this: funcgraph_entry: func=0xffffffff depth=38982 funcgraph_entry: func=0x1ffffffff depth=16044 funcgraph_exit: func=0xffffffff overrun=0x92539aaf00000000 calltime=0x92539c9900000072 rettime=0x100000072 depth=11084 funcgraph_exit: func=0xffffffff overrun=0x9253946e00000000 calltime=0x92539e2100000072 rettime=0x72 depth=26033702 funcgraph_entry: func=0xffffffff depth=85798 funcgraph_entry: func=0x1ffffffff depth=12044 The reason was because the tracefs/events/ftrace/funcgraph_entry/exit format file was incorrect. The -rt kernel adds more common fields to the trace events. Namely, common_migrate_disable and common_preempt_lazy_count. Each is one byte in size. This changes the alignment of the normal payload. Most events are aligned normally, but the function and function graph events are defined with a "PACKED" macro, that packs their payload. As the offsets displayed in the format files are now calculated by an aligned field, the aligned field for function and function graph events should be 1, not their normal alignment. With aligning of the funcgraph_entry event, the format file has: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:unsigned char common_migrate_disable; offset:8; size:1; signed:0; field:unsigned char common_preempt_lazy_count; offset:9; size:1; signed:0; field:unsigned long func; offset:16; size:8; signed:0; field:int depth; offset:24; size:4; signed:1; But the actual alignment is: field:unsigned short common_type; offset:0; size:2; signed:0; field:unsigned char common_flags; offset:2; size:1; signed:0; field:unsigned char common_preempt_count; offset:3; size:1; signed:0; field:int common_pid; offset:4; size:4; signed:1; field:unsigned char common_migrate_disable; offset:8; size:1; signed:0; field:unsigned char common_preempt_lazy_count; offset:9; size:1; signed:0; field:unsigned long func; offset:12; size:8; signed:0; field:int depth; offset:20; size:4; signed:1; Link: https://lkml.kernel.org/r/20200609220041.2a3b527f@oasis.local.home Cc: stable@vger.kernel.org Fixes: 04ae87a52074e ("ftrace: Rework event_create_dir()") Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.h | 3 +++ kernel/trace/trace_entries.h | 14 +++++++------- kernel/trace/trace_export.c | 16 ++++++++++++++++ 3 files changed, 26 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index def769df5bf1..13db4000af3f 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -61,6 +61,9 @@ enum trace_type { #undef __field_desc #define __field_desc(type, container, item) +#undef __field_packed +#define __field_packed(type, container, item) + #undef __array #define __array(type, item, size) type item[size]; diff --git a/kernel/trace/trace_entries.h b/kernel/trace/trace_entries.h index a523da0dae0a..18c4a58aff79 100644 --- a/kernel/trace/trace_entries.h +++ b/kernel/trace/trace_entries.h @@ -78,8 +78,8 @@ FTRACE_ENTRY_PACKED(funcgraph_entry, ftrace_graph_ent_entry, F_STRUCT( __field_struct( struct ftrace_graph_ent, graph_ent ) - __field_desc( unsigned long, graph_ent, func ) - __field_desc( int, graph_ent, depth ) + __field_packed( unsigned long, graph_ent, func ) + __field_packed( int, graph_ent, depth ) ), F_printk("--> %ps (%d)", (void *)__entry->func, __entry->depth) @@ -92,11 +92,11 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, F_STRUCT( __field_struct( struct ftrace_graph_ret, ret ) - __field_desc( unsigned long, ret, func ) - __field_desc( unsigned long, ret, overrun ) - __field_desc( unsigned long long, ret, calltime) - __field_desc( unsigned long long, ret, rettime ) - __field_desc( int, ret, depth ) + __field_packed( unsigned long, ret, func ) + __field_packed( unsigned long, ret, overrun ) + __field_packed( unsigned long long, ret, calltime) + __field_packed( unsigned long long, ret, rettime ) + __field_packed( int, ret, depth ) ), F_printk("<-- %ps (%d) (start: %llx end: %llx) over: %d", diff --git a/kernel/trace/trace_export.c b/kernel/trace/trace_export.c index 77ce5a3b6773..70d3d0a09053 100644 --- a/kernel/trace/trace_export.c +++ b/kernel/trace/trace_export.c @@ -45,6 +45,9 @@ static int ftrace_event_register(struct trace_event_call *call, #undef __field_desc #define __field_desc(type, container, item) type item; +#undef __field_packed +#define __field_packed(type, container, item) type item; + #undef __array #define __array(type, item, size) type item[size]; @@ -85,6 +88,13 @@ static void __always_unused ____ftrace_check_##name(void) \ .size = sizeof(_type), .align = __alignof__(_type), \ is_signed_type(_type), .filter_type = _filter_type }, + +#undef __field_ext_packed +#define __field_ext_packed(_type, _item, _filter_type) { \ + .type = #_type, .name = #_item, \ + .size = sizeof(_type), .align = 1, \ + is_signed_type(_type), .filter_type = _filter_type }, + #undef __field #define __field(_type, _item) __field_ext(_type, _item, FILTER_OTHER) @@ -94,6 +104,9 @@ static void __always_unused ____ftrace_check_##name(void) \ #undef __field_desc #define __field_desc(_type, _container, _item) __field_ext(_type, _item, FILTER_OTHER) +#undef __field_packed +#define __field_packed(_type, _container, _item) __field_ext_packed(_type, _item, FILTER_OTHER) + #undef __array #define __array(_type, _item, _len) { \ .type = #_type"["__stringify(_len)"]", .name = #_item, \ @@ -129,6 +142,9 @@ static struct trace_event_fields ftrace_event_fields_##name[] = { \ #undef __field_desc #define __field_desc(type, container, item) +#undef __field_packed +#define __field_packed(type, container, item) + #undef __array #define __array(type, item, len) -- cgit From 48a42f5d138435242529726b8802076a24b6db17 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Wed, 10 Jun 2020 11:32:51 +0800 Subject: trace: Fix typo in allocate_ftrace_ops()'s comment No functional change, just correct the word. Link: https://lkml.kernel.org/r/20200610033251.31713-1-richard.weiyang@linux.alibaba.com Signed-off-by: Wei Yang Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_functions.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel') diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c index 8a4c8d5c2c98..dd4dff71d89a 100644 --- a/kernel/trace/trace_functions.c +++ b/kernel/trace/trace_functions.c @@ -42,7 +42,7 @@ static int allocate_ftrace_ops(struct trace_array *tr) if (!ops) return -ENOMEM; - /* Currently only the non stack verision is supported */ + /* Currently only the non stack version is supported */ ops->func = function_trace_call; ops->flags = FTRACE_OPS_FL_RECURSION_SAFE | FTRACE_OPS_FL_PID; -- cgit From 3aa8fdc37d16735e8891035becf25b3857d3efe0 Mon Sep 17 00:00:00 2001 From: Vamshi K Sthambamkadi Date: Mon, 15 Jun 2020 20:00:38 +0530 Subject: tracing/probe: Fix memleak in fetch_op_data operations kmemleak report: [<57dcc2ca>] __kmalloc_track_caller+0x139/0x2b0 [] kstrndup+0x37/0x80 [] parse_probe_arg.isra.7+0x3cc/0x630 [<055bf2ba>] traceprobe_parse_probe_arg+0x2f5/0x810 [<655a7766>] trace_kprobe_create+0x2ca/0x950 [<4fc6a02a>] create_or_delete_trace_kprobe+0xf/0x30 [<6d1c8a52>] trace_run_command+0x67/0x80 [] trace_parse_run_command+0xa7/0x140 [] probes_write+0x10/0x20 [<2027641c>] __vfs_write+0x30/0x1e0 [<6a4aeee1>] vfs_write+0x96/0x1b0 [<3517fb7d>] ksys_write+0x53/0xc0 [] __ia32_sys_write+0x15/0x20 [] do_syscall_32_irqs_on+0x3d/0x260 [] do_fast_syscall_32+0x39/0xb0 [] entry_SYSENTER_32+0xaf/0x102 Post parse_probe_arg(), the FETCH_OP_DATA operation type is overwritten to FETCH_OP_ST_STRING, as a result memory is never freed since traceprobe_free_probe_arg() iterates only over SYMBOL and DATA op types Setup fetch string operation correctly after fetch_op_data operation. Link: https://lkml.kernel.org/r/20200615143034.GA1734@cosmos Cc: stable@vger.kernel.org Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support") Acked-by: Masami Hiramatsu Signed-off-by: Vamshi K Sthambamkadi Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace_probe.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index b8a928e925c7..d2867ccc6aca 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -639,8 +639,8 @@ static int traceprobe_parse_probe_arg_body(char *arg, ssize_t *size, ret = -EINVAL; goto fail; } - if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) || - parg->count) { + if ((code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM || + code->op == FETCH_OP_DATA) || parg->count) { /* * IMM, DATA and COMM is pointing actual address, those * must be kept, and if parg->count != 0, this is an -- cgit From 69243720c0932b8672e571a873c78bcf3326575a Mon Sep 17 00:00:00 2001 From: YangHui Date: Tue, 16 Jun 2020 11:36:46 +0800 Subject: tracing: Remove unused event variable in tracing_iter_reset We do not use the event variable, just remove it. Signed-off-by: YangHui Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/trace.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index ec44b0e2a19c..bb62269724d5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -3570,7 +3570,6 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos) void tracing_iter_reset(struct trace_iterator *iter, int cpu) { - struct ring_buffer_event *event; struct ring_buffer_iter *buf_iter; unsigned long entries = 0; u64 ts; @@ -3588,7 +3587,7 @@ void tracing_iter_reset(struct trace_iterator *iter, int cpu) * that a reset never took place on a cpu. This is evident * by the timestamp being before the start of the buffer. */ - while ((event = ring_buffer_iter_peek(buf_iter, &ts))) { + while (ring_buffer_iter_peek(buf_iter, &ts)) { if (ts >= iter->array_buffer->time_start) break; entries++; -- cgit From 026bb845b0fff6dec91fe24511dad7d3067dc3ed Mon Sep 17 00:00:00 2001 From: Kaitao Cheng Date: Fri, 29 May 2020 22:12:14 +0800 Subject: ftrace: Fix maybe-uninitialized compiler warning During build compiler reports some 'false positive' warnings about variables {'seq_ops', 'filtered_pids', 'other_pids'} may be used uninitialized. This patch silences these warnings. Also delete some useless spaces Link: https://lkml.kernel.org/r/20200529141214.37648-1-pilgrimtao@gmail.com Signed-off-by: Kaitao Cheng Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index c163c3531faf..1903b80db6eb 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2260,7 +2260,7 @@ ftrace_find_tramp_ops_next(struct dyn_ftrace *rec, if (hash_contains_ip(ip, op->func_hash)) return op; - } + } return NULL; } @@ -3599,7 +3599,7 @@ static int t_show(struct seq_file *m, void *v) if (direct) seq_printf(m, "\n\tdirect-->%pS", (void *)direct); } - } + } seq_putc(m, '\n'); @@ -7151,6 +7151,10 @@ static int pid_open(struct inode *inode, struct file *file, int type) case TRACE_NO_PIDS: seq_ops = &ftrace_no_pid_sops; break; + default: + trace_array_put(tr); + WARN_ON_ONCE(1); + return -EINVAL; } ret = seq_open(file, seq_ops); @@ -7229,6 +7233,10 @@ pid_write(struct file *filp, const char __user *ubuf, other_pids = rcu_dereference_protected(tr->function_pids, lockdep_is_held(&ftrace_lock)); break; + default: + ret = -EINVAL; + WARN_ON_ONCE(1); + goto out; } ret = trace_pid_write(filtered_pids, &pid_list, ubuf, cnt); -- cgit