October 2022 - Linux-stable-mirror

FAILED: patch "[PATCH] tracing: Move duplicate code of trace_kprobe/eprobe.c into" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: f1d3cbfaafc1 ("tracing: Move duplicate code of trace_kprobe/eprobe.c into header") 7491e2c44278 ("tracing: Add a probe that attaches to trace events") 007517a01995 ("tracing/probe: Change traceprobe_set_print_fmt() to take a type") bc87cf0a08d4 ("trace: Add a generic function to read/write u64 values from tracefs") d262271d0483 ("tracing/dynevent: Delegate parsing to create function") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From f1d3cbfaafc10464550c6d3a125f4fc802bbaed5 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 12 Oct 2022 06:40:56 -0400 Subject: [PATCH] tracing: Move duplicate code of trace_kprobe/eprobe.c into header The functions: fetch_store_strlen_user() fetch_store_strlen() fetch_store_string_user() fetch_store_string() are identical in both trace_kprobe.c and trace_eprobe.c. Move them into a new header file trace_probe_kernel.h to share it. This code will later be used by the synthetic events as well. Marked for stable as a fix for a crash in synthetic events requires it. Link: https://lkml.kernel.org/r/20221012104534.467668078@goodmis.org Cc: stable(a)vger.kernel.org Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: Tom Zanussi <zanussi(a)kernel.org> Acked-by: Masami Hiramatsu (Google) <mhiramat(a)kernel.org> Reviewed-by: Tom Zanussi <zanussi(a)kernel.org> Fixes: bd82631d7ccdc ("tracing: Add support for dynamic strings to synthetic events") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c index c08bde9871ec..5dd0617e5df6 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -16,6 +16,7 @@ #include "trace_dynevent.h" #include "trace_probe.h" #include "trace_probe_tmpl.h" +#include "trace_probe_kernel.h" #define EPROBE_EVENT_SYSTEM "eprobes" @@ -456,29 +457,14 @@ NOKPROBE_SYMBOL(process_fetch_insn) static nokprobe_inline int fetch_store_strlen_user(unsigned long addr) { - const void __user *uaddr = (__force const void __user *)addr; - - return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); + return kern_fetch_store_strlen_user(addr); } /* Return the length of string -- including null terminal byte */ static nokprobe_inline int fetch_store_strlen(unsigned long addr) { - int ret, len = 0; - u8 c; - -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE - if (addr < TASK_SIZE) - return fetch_store_strlen_user(addr); -#endif - - do { - ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); - len++; - } while (c && ret == 0 && len < MAX_STRING_SIZE); - - return (ret < 0) ? ret : len; + return kern_fetch_store_strlen(addr); } /* @@ -488,21 +474,7 @@ fetch_store_strlen(unsigned long addr) static nokprobe_inline int fetch_store_string_user(unsigned long addr, void *dest, void *base) { - const void __user *uaddr = (__force const void __user *)addr; - int maxlen = get_loc_len(*(u32 *)dest); - void *__dest; - long ret; - - if (unlikely(!maxlen)) - return -ENOMEM; - - __dest = get_loc_data(dest, base); - - ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); - - return ret; + return kern_fetch_store_string_user(addr, dest, base); } /* @@ -512,29 +484,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) static nokprobe_inline int fetch_store_string(unsigned long addr, void *dest, void *base) { - int maxlen = get_loc_len(*(u32 *)dest); - void *__dest; - long ret; - -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE - if ((unsigned long)addr < TASK_SIZE) - return fetch_store_string_user(addr, dest, base); -#endif - - if (unlikely(!maxlen)) - return -ENOMEM; - - __dest = get_loc_data(dest, base); - - /* - * Try to get string again, since the string can be changed while - * probing. - */ - ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); - - return ret; + return kern_fetch_store_string(addr, dest, base); } static nokprobe_inline int diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 23f7f0ec4f4c..5a75b039e586 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -20,6 +20,7 @@ #include "trace_kprobe_selftest.h" #include "trace_probe.h" #include "trace_probe_tmpl.h" +#include "trace_probe_kernel.h" #define KPROBE_EVENT_SYSTEM "kprobes" #define KRETPROBE_MAXACTIVE_MAX 4096 @@ -1223,29 +1224,14 @@ static const struct file_operations kprobe_profile_ops = { static nokprobe_inline int fetch_store_strlen_user(unsigned long addr) { - const void __user *uaddr = (__force const void __user *)addr; - - return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); + return kern_fetch_store_strlen_user(addr); } /* Return the length of string -- including null terminal byte */ static nokprobe_inline int fetch_store_strlen(unsigned long addr) { - int ret, len = 0; - u8 c; - -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE - if (addr < TASK_SIZE) - return fetch_store_strlen_user(addr); -#endif - - do { - ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); - len++; - } while (c && ret == 0 && len < MAX_STRING_SIZE); - - return (ret < 0) ? ret : len; + return kern_fetch_store_strlen(addr); } /* @@ -1255,21 +1241,7 @@ fetch_store_strlen(unsigned long addr) static nokprobe_inline int fetch_store_string_user(unsigned long addr, void *dest, void *base) { - const void __user *uaddr = (__force const void __user *)addr; - int maxlen = get_loc_len(*(u32 *)dest); - void *__dest; - long ret; - - if (unlikely(!maxlen)) - return -ENOMEM; - - __dest = get_loc_data(dest, base); - - ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); - - return ret; + return kern_fetch_store_string_user(addr, dest, base); } /* @@ -1279,29 +1251,7 @@ fetch_store_string_user(unsigned long addr, void *dest, void *base) static nokprobe_inline int fetch_store_string(unsigned long addr, void *dest, void *base) { - int maxlen = get_loc_len(*(u32 *)dest); - void *__dest; - long ret; - -#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE - if ((unsigned long)addr < TASK_SIZE) - return fetch_store_string_user(addr, dest, base); -#endif - - if (unlikely(!maxlen)) - return -ENOMEM; - - __dest = get_loc_data(dest, base); - - /* - * Try to get string again, since the string can be changed while - * probing. - */ - ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); - if (ret >= 0) - *(u32 *)dest = make_data_loc(ret, __dest - base); - - return ret; + return kern_fetch_store_string(addr, dest, base); } static nokprobe_inline int diff --git a/kernel/trace/trace_probe_kernel.h b/kernel/trace/trace_probe_kernel.h new file mode 100644 index 000000000000..1d43df29a1f8 --- /dev/null +++ b/kernel/trace/trace_probe_kernel.h @@ -0,0 +1,96 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __TRACE_PROBE_KERNEL_H_ +#define __TRACE_PROBE_KERNEL_H_ + +/* + * This depends on trace_probe.h, but can not include it due to + * the way trace_probe_tmpl.h is used by trace_kprobe.c and trace_eprobe.c. + * Which means that any other user must include trace_probe.h before including + * this file. + */ +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline int +kern_fetch_store_strlen_user(unsigned long addr) +{ + const void __user *uaddr = (__force const void __user *)addr; + + return strnlen_user_nofault(uaddr, MAX_STRING_SIZE); +} + +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline int +kern_fetch_store_strlen(unsigned long addr) +{ + int ret, len = 0; + u8 c; + +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE + if (addr < TASK_SIZE) + return kern_fetch_store_strlen_user(addr); +#endif + + do { + ret = copy_from_kernel_nofault(&c, (u8 *)addr + len, 1); + len++; + } while (c && ret == 0 && len < MAX_STRING_SIZE); + + return (ret < 0) ? ret : len; +} + +/* + * Fetch a null-terminated string from user. Caller MUST set *(u32 *)buf + * with max length and relative data location. + */ +static nokprobe_inline int +kern_fetch_store_string_user(unsigned long addr, void *dest, void *base) +{ + const void __user *uaddr = (__force const void __user *)addr; + int maxlen = get_loc_len(*(u32 *)dest); + void *__dest; + long ret; + + if (unlikely(!maxlen)) + return -ENOMEM; + + __dest = get_loc_data(dest, base); + + ret = strncpy_from_user_nofault(__dest, uaddr, maxlen); + if (ret >= 0) + *(u32 *)dest = make_data_loc(ret, __dest - base); + + return ret; +} + +/* + * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max + * length and relative data location. + */ +static nokprobe_inline int +kern_fetch_store_string(unsigned long addr, void *dest, void *base) +{ + int maxlen = get_loc_len(*(u32 *)dest); + void *__dest; + long ret; + +#ifdef CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE + if ((unsigned long)addr < TASK_SIZE) + return kern_fetch_store_string_user(addr, dest, base); +#endif + + if (unlikely(!maxlen)) + return -ENOMEM; + + __dest = get_loc_data(dest, base); + + /* + * Try to get string again, since the string can be changed while + * probing. + */ + ret = strncpy_from_kernel_nofault(__dest, (void *)addr, maxlen); + if (ret >= 0) + *(u32 *)dest = make_data_loc(ret, __dest - base); + + return ret; +} + +#endif /* __TRACE_PROBE_KERNEL_H_ */

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Do not free snapshot if tracer is on cmdline" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: a541a9559bb0 ("tracing: Do not free snapshot if tracer is on cmdline") f4b0d318097e ("tracing: Simplify conditional compilation code in tracing_set_tracer()") 7440172974e8 ("tracing: Replace synchronize_sched() and call_rcu_sched()") f8a79d5c7ef4 ("tracepoints: Free early tracepoints after RCU is initialized") e0a568dcd18b ("tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()") e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU") 2824f5033248 ("tracing: Make the snapshot trigger work with instances") 80765597bc58 ("tracing: Rewrite filter logic to be simpler and faster") 478325f18865 ("tracing: Clean up and document pred_funcs_##type creation and use") e9baef0d8616 ("tracing: Combine enum and arrays into single macro in filter code") 567f6989fd2a ("tracing: Embed replace_filter_string() helper function") 404a3add43c9 ("tracing: Only add filter list when needed") c7399708b3cd ("tracing: Remove filter allocator helper") 559d421267d1 ("tracing: Use trace_seq instead of open code string appending") a0ff08fd4e3f ("tracing: Remove BUG_ON() from append_filter_string()") 844ccdd7dce2 ("rcu: Eliminate rcu_irq_enter_disabled()") 51a1fd30f130 ("rcu: Make ->dynticks_nesting be a simple counter") 58721f5da4bc ("rcu: Define rcu_irq_{enter,exit}() in terms of rcu_nmi_{enter,exit}()") 6136d6e48a01 ("rcu: Clamp ->dynticks_nmi_nesting at eqs entry/exit") a0eb22bf64a7 ("rcu: Reduce dyntick-idle state space") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a541a9559bb0a8ecc434de01d3e4826c32e8bb53 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 5 Oct 2022 11:37:57 -0400 Subject: [PATCH] tracing: Do not free snapshot if tracer is on cmdline The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Fixes: 45ad21ca5530 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler(a)kernel.org> Tested-by: Ross Zwisler <zwisler(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index def721de68a0..47a44b055a1d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6428,12 +6428,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (tr->current_trace->reset) tr->current_trace->reset(tr); +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + /* Current trace needs to be nop_trace before synchronize_rcu */ tr->current_trace = &nop_trace; -#ifdef CONFIG_TRACER_MAX_TRACE - had_max_tr = tr->allocated_snapshot; - if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that @@ -6446,11 +6446,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) free_snapshot(tr); } - if (t->use_max_tr && !had_max_tr) { + if (t->use_max_tr && !tr->allocated_snapshot) { ret = tracing_alloc_snapshot_instance(tr); if (ret < 0) goto out; } +#else + tr->current_trace = &nop_trace; #endif if (t->init) {

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Do not free snapshot if tracer is on cmdline" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: a541a9559bb0 ("tracing: Do not free snapshot if tracer is on cmdline") f4b0d318097e ("tracing: Simplify conditional compilation code in tracing_set_tracer()") 7440172974e8 ("tracing: Replace synchronize_sched() and call_rcu_sched()") f8a79d5c7ef4 ("tracepoints: Free early tracepoints after RCU is initialized") e0a568dcd18b ("tracing: Fix synchronizing to event changes with tracepoint_synchronize_unregister()") e6753f23d961 ("tracepoint: Make rcuidle tracepoint callers use SRCU") 2824f5033248 ("tracing: Make the snapshot trigger work with instances") 80765597bc58 ("tracing: Rewrite filter logic to be simpler and faster") 478325f18865 ("tracing: Clean up and document pred_funcs_##type creation and use") e9baef0d8616 ("tracing: Combine enum and arrays into single macro in filter code") 567f6989fd2a ("tracing: Embed replace_filter_string() helper function") 404a3add43c9 ("tracing: Only add filter list when needed") c7399708b3cd ("tracing: Remove filter allocator helper") 559d421267d1 ("tracing: Use trace_seq instead of open code string appending") a0ff08fd4e3f ("tracing: Remove BUG_ON() from append_filter_string()") 844ccdd7dce2 ("rcu: Eliminate rcu_irq_enter_disabled()") 51a1fd30f130 ("rcu: Make ->dynticks_nesting be a simple counter") 58721f5da4bc ("rcu: Define rcu_irq_{enter,exit}() in terms of rcu_nmi_{enter,exit}()") 6136d6e48a01 ("rcu: Clamp ->dynticks_nmi_nesting at eqs entry/exit") a0eb22bf64a7 ("rcu: Reduce dyntick-idle state space") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a541a9559bb0a8ecc434de01d3e4826c32e8bb53 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 5 Oct 2022 11:37:57 -0400 Subject: [PATCH] tracing: Do not free snapshot if tracer is on cmdline The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Fixes: 45ad21ca5530 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler(a)kernel.org> Tested-by: Ross Zwisler <zwisler(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index def721de68a0..47a44b055a1d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6428,12 +6428,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (tr->current_trace->reset) tr->current_trace->reset(tr); +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + /* Current trace needs to be nop_trace before synchronize_rcu */ tr->current_trace = &nop_trace; -#ifdef CONFIG_TRACER_MAX_TRACE - had_max_tr = tr->allocated_snapshot; - if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that @@ -6446,11 +6446,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) free_snapshot(tr); } - if (t->use_max_tr && !had_max_tr) { + if (t->use_max_tr && !tr->allocated_snapshot) { ret = tracing_alloc_snapshot_instance(tr); if (ret < 0) goto out; } +#else + tr->current_trace = &nop_trace; #endif if (t->init) {

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Do not free snapshot if tracer is on cmdline" failed to apply to 4.19-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: a541a9559bb0 ("tracing: Do not free snapshot if tracer is on cmdline") f4b0d318097e ("tracing: Simplify conditional compilation code in tracing_set_tracer()") 7440172974e8 ("tracing: Replace synchronize_sched() and call_rcu_sched()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a541a9559bb0a8ecc434de01d3e4826c32e8bb53 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 5 Oct 2022 11:37:57 -0400 Subject: [PATCH] tracing: Do not free snapshot if tracer is on cmdline The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Fixes: 45ad21ca5530 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler(a)kernel.org> Tested-by: Ross Zwisler <zwisler(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index def721de68a0..47a44b055a1d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6428,12 +6428,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (tr->current_trace->reset) tr->current_trace->reset(tr); +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + /* Current trace needs to be nop_trace before synchronize_rcu */ tr->current_trace = &nop_trace; -#ifdef CONFIG_TRACER_MAX_TRACE - had_max_tr = tr->allocated_snapshot; - if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that @@ -6446,11 +6446,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) free_snapshot(tr); } - if (t->use_max_tr && !had_max_tr) { + if (t->use_max_tr && !tr->allocated_snapshot) { ret = tracing_alloc_snapshot_instance(tr); if (ret < 0) goto out; } +#else + tr->current_trace = &nop_trace; #endif if (t->init) {

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Do not free snapshot if tracer is on cmdline" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: a541a9559bb0 ("tracing: Do not free snapshot if tracer is on cmdline") f4b0d318097e ("tracing: Simplify conditional compilation code in tracing_set_tracer()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a541a9559bb0a8ecc434de01d3e4826c32e8bb53 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 5 Oct 2022 11:37:57 -0400 Subject: [PATCH] tracing: Do not free snapshot if tracer is on cmdline The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Fixes: 45ad21ca5530 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler(a)kernel.org> Tested-by: Ross Zwisler <zwisler(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index def721de68a0..47a44b055a1d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6428,12 +6428,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (tr->current_trace->reset) tr->current_trace->reset(tr); +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + /* Current trace needs to be nop_trace before synchronize_rcu */ tr->current_trace = &nop_trace; -#ifdef CONFIG_TRACER_MAX_TRACE - had_max_tr = tr->allocated_snapshot; - if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that @@ -6446,11 +6446,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) free_snapshot(tr); } - if (t->use_max_tr && !had_max_tr) { + if (t->use_max_tr && !tr->allocated_snapshot) { ret = tracing_alloc_snapshot_instance(tr); if (ret < 0) goto out; } +#else + tr->current_trace = &nop_trace; #endif if (t->init) {

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Do not free snapshot if tracer is on cmdline" failed to apply to 5.10-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: a541a9559bb0 ("tracing: Do not free snapshot if tracer is on cmdline") f4b0d318097e ("tracing: Simplify conditional compilation code in tracing_set_tracer()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a541a9559bb0a8ecc434de01d3e4826c32e8bb53 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 5 Oct 2022 11:37:57 -0400 Subject: [PATCH] tracing: Do not free snapshot if tracer is on cmdline The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Fixes: 45ad21ca5530 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler(a)kernel.org> Tested-by: Ross Zwisler <zwisler(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index def721de68a0..47a44b055a1d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6428,12 +6428,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (tr->current_trace->reset) tr->current_trace->reset(tr); +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + /* Current trace needs to be nop_trace before synchronize_rcu */ tr->current_trace = &nop_trace; -#ifdef CONFIG_TRACER_MAX_TRACE - had_max_tr = tr->allocated_snapshot; - if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that @@ -6446,11 +6446,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) free_snapshot(tr); } - if (t->use_max_tr && !had_max_tr) { + if (t->use_max_tr && !tr->allocated_snapshot) { ret = tracing_alloc_snapshot_instance(tr); if (ret < 0) goto out; } +#else + tr->current_trace = &nop_trace; #endif if (t->init) {

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Do not free snapshot if tracer is on cmdline" failed to apply to 5.15-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: a541a9559bb0 ("tracing: Do not free snapshot if tracer is on cmdline") f4b0d318097e ("tracing: Simplify conditional compilation code in tracing_set_tracer()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From a541a9559bb0a8ecc434de01d3e4826c32e8bb53 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 5 Oct 2022 11:37:57 -0400 Subject: [PATCH] tracing: Do not free snapshot if tracer is on cmdline The ftrace_boot_snapshot and alloc_snapshot cmdline options allocate the snapshot buffer at boot up for use later. The ftrace_boot_snapshot in particular requires the snapshot to be allocated because it will take a snapshot at the end of boot up allowing to see the traces that happened during boot so that it's not lost when user space takes over. When a tracer is registered (started) there's a path that checks if it requires the snapshot buffer or not, and if it does not and it was allocated it will do a synchronization and free the snapshot buffer. This is only required if the previous tracer was using it for "max latency" snapshots, as it needs to make sure all max snapshots are complete before freeing. But this is only needed if the previous tracer was using the snapshot buffer for latency (like irqoff tracer and friends). But it does not make sense to free it, if the previous tracer was not using it, and the snapshot was allocated by the cmdline parameters. This basically takes away the point of allocating it in the first place! Note, the allocated snapshot worked fine for just trace events, but fails when a tracer is enabled on the cmdline. Further investigation, this goes back even further and it does not require a tracer on the cmdline to fail. Simply enable snapshots and then enable a tracer, and it will remove the snapshot. Link: https://lkml.kernel.org/r/20221005113757.041df7fe@gandalf.local.home Cc: Masami Hiramatsu <mhiramat(a)kernel.org> Cc: Andrew Morton <akpm(a)linux-foundation.org> Cc: stable(a)vger.kernel.org Fixes: 45ad21ca5530 ("tracing: Have trace_array keep track if snapshot buffer is allocated") Reported-by: Ross Zwisler <zwisler(a)kernel.org> Tested-by: Ross Zwisler <zwisler(a)kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index def721de68a0..47a44b055a1d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -6428,12 +6428,12 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) if (tr->current_trace->reset) tr->current_trace->reset(tr); +#ifdef CONFIG_TRACER_MAX_TRACE + had_max_tr = tr->current_trace->use_max_tr; + /* Current trace needs to be nop_trace before synchronize_rcu */ tr->current_trace = &nop_trace; -#ifdef CONFIG_TRACER_MAX_TRACE - had_max_tr = tr->allocated_snapshot; - if (had_max_tr && !t->use_max_tr) { /* * We need to make sure that the update_max_tr sees that @@ -6446,11 +6446,13 @@ int tracing_set_tracer(struct trace_array *tr, const char *buf) free_snapshot(tr); } - if (t->use_max_tr && !had_max_tr) { + if (t->use_max_tr && !tr->allocated_snapshot) { ret = tracing_alloc_snapshot_instance(tr); if (ret < 0) goto out; } +#else + tr->current_trace = &nop_trace; #endif if (t->init) {

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Wake up waiters when tracing is disabled" failed to apply to 4.9-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 2b0fd9a59b79 ("tracing: Wake up waiters when tracing is disabled") f3ddb74ad079 ("tracing: Wake up ring buffer waiters on closing of the file") efbbdaa22bb7 ("tracing: Show real address for trace event arguments") 8e99cf91b99b ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic") ff895103a84a ("tracing: Save off entry when peeking at next entry") 03329f993978 ("tracing: Add tracefs file buffer_percentage") 2c2b0a78b373 ("ring-buffer: Add percentage of ring buffer full to wake up reader") 2c1ea60b195d ("tracing: Add timestamp_mode trace file") 00b4145298ae ("ring-buffer: Add interface for setting absolute time stamps") ecf927000ce3 ("ring_buffer_poll_wait() return value used as return value of ->poll()") 065e63f95143 ("tracing: Only have rmmod clear buffers that its events were active in") dc8d387210e3 ("tracing: Update Documentation/trace/ftrace.txt") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b0fd9a59b7990c161fa1cb7b79edb22847c87c2 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 28 Sep 2022 18:22:20 -0400 Subject: [PATCH] tracing: Wake up waiters when tracing is disabled When tracing is disabled, there's no reason that waiters should stay waiting, wake them up, otherwise tasks get stuck when they should be flushing the buffers. Cc: stable(a)vger.kernel.org Fixes: e30f53aad2202 ("tracing: Do not busy wait in buffer splice") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 58afc83afc9d..bb5597c6bfc1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8334,6 +8334,10 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, if (ret) goto out; + /* No need to wait after waking up when tracing is off */ + if (!tracer_tracing_is_on(iter->tr)) + goto out; + /* Make sure we see the new wait_index */ smp_rmb(); if (wait_index != iter->wait_index) @@ -9065,6 +9069,8 @@ rb_simple_write(struct file *filp, const char __user *ubuf, tracer_tracing_off(tr); if (tr->current_trace->stop) tr->current_trace->stop(tr); + /* Wake up any waiters */ + ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS); } mutex_unlock(&trace_types_lock); }

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Wake up waiters when tracing is disabled" failed to apply to 4.14-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 4.14-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 2b0fd9a59b79 ("tracing: Wake up waiters when tracing is disabled") f3ddb74ad079 ("tracing: Wake up ring buffer waiters on closing of the file") efbbdaa22bb7 ("tracing: Show real address for trace event arguments") 8e99cf91b99b ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic") ff895103a84a ("tracing: Save off entry when peeking at next entry") 03329f993978 ("tracing: Add tracefs file buffer_percentage") 2c2b0a78b373 ("ring-buffer: Add percentage of ring buffer full to wake up reader") 2c1ea60b195d ("tracing: Add timestamp_mode trace file") 00b4145298ae ("ring-buffer: Add interface for setting absolute time stamps") ecf927000ce3 ("ring_buffer_poll_wait() return value used as return value of ->poll()") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b0fd9a59b7990c161fa1cb7b79edb22847c87c2 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 28 Sep 2022 18:22:20 -0400 Subject: [PATCH] tracing: Wake up waiters when tracing is disabled When tracing is disabled, there's no reason that waiters should stay waiting, wake them up, otherwise tasks get stuck when they should be flushing the buffers. Cc: stable(a)vger.kernel.org Fixes: e30f53aad2202 ("tracing: Do not busy wait in buffer splice") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 58afc83afc9d..bb5597c6bfc1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8334,6 +8334,10 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, if (ret) goto out; + /* No need to wait after waking up when tracing is off */ + if (!tracer_tracing_is_on(iter->tr)) + goto out; + /* Make sure we see the new wait_index */ smp_rmb(); if (wait_index != iter->wait_index) @@ -9065,6 +9069,8 @@ rb_simple_write(struct file *filp, const char __user *ubuf, tracer_tracing_off(tr); if (tr->current_trace->stop) tr->current_trace->stop(tr); + /* Wake up any waiters */ + ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS); } mutex_unlock(&trace_types_lock); }

2 years, 2 months

1
0
0 0

FAILED: patch "[PATCH] tracing: Wake up waiters when tracing is disabled" failed to apply to 5.4-stable tree

by gregkh＠linuxfoundation.org

The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable(a)vger.kernel.org>. Possible dependencies: 2b0fd9a59b79 ("tracing: Wake up waiters when tracing is disabled") f3ddb74ad079 ("tracing: Wake up ring buffer waiters on closing of the file") efbbdaa22bb7 ("tracing: Show real address for trace event arguments") 8e99cf91b99b ("tracing: Do not allocate buffer in trace_find_next_entry() in atomic") ff895103a84a ("tracing: Save off entry when peeking at next entry") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ From 2b0fd9a59b7990c161fa1cb7b79edb22847c87c2 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" <rostedt(a)goodmis.org> Date: Wed, 28 Sep 2022 18:22:20 -0400 Subject: [PATCH] tracing: Wake up waiters when tracing is disabled When tracing is disabled, there's no reason that waiters should stay waiting, wake them up, otherwise tasks get stuck when they should be flushing the buffers. Cc: stable(a)vger.kernel.org Fixes: e30f53aad2202 ("tracing: Do not busy wait in buffer splice") Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 58afc83afc9d..bb5597c6bfc1 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8334,6 +8334,10 @@ tracing_buffers_splice_read(struct file *file, loff_t *ppos, if (ret) goto out; + /* No need to wait after waking up when tracing is off */ + if (!tracer_tracing_is_on(iter->tr)) + goto out; + /* Make sure we see the new wait_index */ smp_rmb(); if (wait_index != iter->wait_index) @@ -9065,6 +9069,8 @@ rb_simple_write(struct file *filp, const char __user *ubuf, tracer_tracing_off(tr); if (tr->current_trace->stop) tr->current_trace->stop(tr); + /* Wake up any waiters */ + ring_buffer_wake_waiters(buffer, RING_BUFFER_ALL_CPUS); } mutex_unlock(&trace_types_lock); }

2 years, 2 months

1
0
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-stable-mirror October 2022