From 1c1377d7b60c2d96eefab0bd9740d4a27fb0e1d3 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:52 -0800 Subject: [PATCH 1/8] netconsole: consolidate send buffers into netconsole_target struct Move the static buffers from send_msg_no_fragmentation() and send_msg_fragmented() into the netconsole_target structure. This simplifies the code by: - Eliminating redundant static buffers - Centralizing buffer management in the target structure - Reducing memory usage by 1KB (one buffer instead of two) The buffer in netconsole_target is protected by target_list_lock, maintaining the same synchronization semantics as the original code. Suggested-by: Jakub Kicinski Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/netconsole.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 86ab4a42769a..034caaa26563 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -123,6 +123,7 @@ struct netconsole_target_stats { * remote_ip (read-write) * local_mac (read-only) * remote_mac (read-write) + * @buf: The buffer used to send the full msg to the network stack */ struct netconsole_target { struct list_head list; @@ -137,6 +138,8 @@ struct netconsole_target { bool extended; bool release; struct netpoll np; + /* protected by target_list_lock */ + char buf[MAX_PRINT_CHUNK]; }; #ifdef CONFIG_NETCONSOLE_DYNAMIC @@ -1117,7 +1120,6 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, int msg_len, int release_len) { - static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ const char *userdata = NULL; const char *release; @@ -1128,18 +1130,18 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, if (release_len) { release = init_utsname()->release; - scnprintf(buf, MAX_PRINT_CHUNK, "%s,%s", release, msg); + scnprintf(nt->buf, MAX_PRINT_CHUNK, "%s,%s", release, msg); msg_len += release_len; } else { - memcpy(buf, msg, msg_len); + memcpy(nt->buf, msg, msg_len); } if (userdata) - msg_len += scnprintf(&buf[msg_len], + msg_len += scnprintf(&nt->buf[msg_len], MAX_PRINT_CHUNK - msg_len, "%s", userdata); - send_udp(nt, buf, msg_len); + send_udp(nt, nt->buf, msg_len); } static void append_release(char *buf) @@ -1150,7 +1152,7 @@ static void append_release(char *buf) scnprintf(buf, MAX_PRINT_CHUNK, "%s,", release); } -static void send_fragmented_body(struct netconsole_target *nt, char *buf, +static void send_fragmented_body(struct netconsole_target *nt, const char *msgbody, int header_len, int msgbody_len) { @@ -1181,7 +1183,7 @@ static void send_fragmented_body(struct netconsole_target *nt, char *buf, int this_offset = 0; int this_chunk = 0; - this_header += scnprintf(buf + this_header, + this_header += scnprintf(nt->buf + this_header, MAX_PRINT_CHUNK - this_header, ",ncfrag=%d/%d;", offset, body_len); @@ -1192,7 +1194,8 @@ static void send_fragmented_body(struct netconsole_target *nt, char *buf, MAX_PRINT_CHUNK - this_header); if (WARN_ON_ONCE(this_chunk <= 0)) return; - memcpy(buf + this_header, msgbody + offset, this_chunk); + memcpy(nt->buf + this_header, msgbody + offset, + this_chunk); this_offset += this_chunk; } @@ -1226,13 +1229,13 @@ static void send_fragmented_body(struct netconsole_target *nt, char *buf, */ return; - memcpy(buf + this_header + this_offset, + memcpy(nt->buf + this_header + this_offset, userdata + sent_userdata, this_chunk); this_offset += this_chunk; } - send_udp(nt, buf, this_header + this_offset); + send_udp(nt, nt->buf, this_header + this_offset); offset += this_offset; } } @@ -1242,7 +1245,6 @@ static void send_msg_fragmented(struct netconsole_target *nt, int msg_len, int release_len) { - static char buf[MAX_PRINT_CHUNK]; /* protected by target_list_lock */ int header_len, msgbody_len; const char *msgbody; @@ -1260,16 +1262,16 @@ static void send_msg_fragmented(struct netconsole_target *nt, * "ncfrag=/" */ if (release_len) - append_release(buf); + append_release(nt->buf); /* Copy the header into the buffer */ - memcpy(buf + release_len, msg, header_len); + memcpy(nt->buf + release_len, msg, header_len); header_len += release_len; /* for now on, the header will be persisted, and the msgbody * will be replaced */ - send_fragmented_body(nt, buf, msgbody, header_len, msgbody_len); + send_fragmented_body(nt, msgbody, header_len, msgbody_len); } /** From 4205f6495eea62c7f4042346e045e4ac706e1830 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:53 -0800 Subject: [PATCH 2/8] netconsole: Rename userdata to extradata Rename "userdata" to "extradata" since this structure will hold both user and system data in future patches. Keep "userdata" term only for data that comes from userspace (configfs), while "extradata" encompasses both userdata and future kerneldata. These are the rules of the design 1. extradata_complete will hold userdata and sysdata (coming) 2. sysdata will come after userdata_length 3. extradata_complete[userdata_length] string will be replaced at every message 5. userdata is replaced when configfs changes (update_userdata()) 6. sysdata is replaced at every message Example: extradata_complete = "userkey=uservalue cpu=42" userdata_length = 17 sysdata_length = 7 (space (" ") is part of sysdata) Since sysdata is still not available, you will see the following in the send functions: extradata_len = nt->userdata_length; The upcoming patches will, which will add support for sysdata, will change it to: extradata_len = nt->userdata_length + sysdata_len; Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/netconsole.c | 87 ++++++++++++++++++++-------------------- 1 file changed, 44 insertions(+), 43 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 034caaa26563..7f05c7f74c31 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -45,12 +45,12 @@ MODULE_DESCRIPTION("Console driver for network interfaces"); MODULE_LICENSE("GPL"); #define MAX_PARAM_LENGTH 256 -#define MAX_USERDATA_ENTRY_LENGTH 256 -#define MAX_USERDATA_VALUE_LENGTH 200 +#define MAX_EXTRADATA_ENTRY_LEN 256 +#define MAX_EXTRADATA_VALUE_LEN 200 /* The number 3 comes from userdata entry format characters (' ', '=', '\n') */ -#define MAX_USERDATA_NAME_LENGTH (MAX_USERDATA_ENTRY_LENGTH - \ - MAX_USERDATA_VALUE_LENGTH - 3) -#define MAX_USERDATA_ITEMS 16 +#define MAX_EXTRADATA_NAME_LEN (MAX_EXTRADATA_ENTRY_LEN - \ + MAX_EXTRADATA_VALUE_LEN - 3) +#define MAX_EXTRADATA_ITEMS 16 #define MAX_PRINT_CHUNK 1000 static char config[MAX_PARAM_LENGTH]; @@ -102,8 +102,8 @@ struct netconsole_target_stats { * @list: Links this target into the target_list. * @group: Links us into the configfs subsystem hierarchy. * @userdata_group: Links to the userdata configfs hierarchy - * @userdata_complete: Cached, formatted string of append - * @userdata_length: String length of userdata_complete + * @extradata_complete: Cached, formatted string of append + * @userdata_length: String length of usedata in extradata_complete. * @stats: Packet send stats for the target. Used for debugging. * @enabled: On / off knob to enable / disable target. * Visible from userspace (read-write). @@ -130,7 +130,7 @@ struct netconsole_target { #ifdef CONFIG_NETCONSOLE_DYNAMIC struct config_group group; struct config_group userdata_group; - char userdata_complete[MAX_USERDATA_ENTRY_LENGTH * MAX_USERDATA_ITEMS]; + char extradata_complete[MAX_EXTRADATA_ENTRY_LEN * MAX_EXTRADATA_ITEMS]; size_t userdata_length; #endif struct netconsole_target_stats stats; @@ -690,7 +690,7 @@ out_unlock: struct userdatum { struct config_item item; - char value[MAX_USERDATA_VALUE_LENGTH]; + char value[MAX_EXTRADATA_VALUE_LEN]; }; static struct userdatum *to_userdatum(struct config_item *item) @@ -727,13 +727,13 @@ static void update_userdata(struct netconsole_target *nt) /* Clear the current string in case the last userdatum was deleted */ nt->userdata_length = 0; - nt->userdata_complete[0] = 0; + nt->extradata_complete[0] = 0; list_for_each(entry, &nt->userdata_group.cg_children) { struct userdatum *udm_item; struct config_item *item; - if (WARN_ON_ONCE(child_count >= MAX_USERDATA_ITEMS)) + if (WARN_ON_ONCE(child_count >= MAX_EXTRADATA_ITEMS)) break; child_count++; @@ -741,19 +741,19 @@ static void update_userdata(struct netconsole_target *nt) udm_item = to_userdatum(item); /* Skip userdata with no value set */ - if (strnlen(udm_item->value, MAX_USERDATA_VALUE_LENGTH) == 0) + if (strnlen(udm_item->value, MAX_EXTRADATA_VALUE_LEN) == 0) continue; - /* This doesn't overflow userdata_complete since it will write - * one entry length (1/MAX_USERDATA_ITEMS long), entry count is + /* This doesn't overflow extradata_complete since it will write + * one entry length (1/MAX_EXTRADATA_ITEMS long), entry count is * checked to not exceed MAX items with child_count above */ - complete_idx += scnprintf(&nt->userdata_complete[complete_idx], - MAX_USERDATA_ENTRY_LENGTH, " %s=%s\n", + complete_idx += scnprintf(&nt->extradata_complete[complete_idx], + MAX_EXTRADATA_ENTRY_LEN, " %s=%s\n", item->ci_name, udm_item->value); } - nt->userdata_length = strnlen(nt->userdata_complete, - sizeof(nt->userdata_complete)); + nt->userdata_length = strnlen(nt->extradata_complete, + sizeof(nt->extradata_complete)); } static ssize_t userdatum_value_store(struct config_item *item, const char *buf, @@ -764,7 +764,7 @@ static ssize_t userdatum_value_store(struct config_item *item, const char *buf, struct userdata *ud; ssize_t ret; - if (count > MAX_USERDATA_VALUE_LENGTH) + if (count > MAX_EXTRADATA_VALUE_LEN) return -EMSGSIZE; mutex_lock(&dynamic_netconsole_mutex); @@ -813,13 +813,13 @@ static struct config_item *userdatum_make_item(struct config_group *group, struct userdata *ud; size_t child_count; - if (strlen(name) > MAX_USERDATA_NAME_LENGTH) + if (strlen(name) > MAX_EXTRADATA_NAME_LEN) return ERR_PTR(-ENAMETOOLONG); ud = to_userdata(&group->cg_item); nt = userdata_to_target(ud); child_count = list_count_nodes(&nt->userdata_group.cg_children); - if (child_count >= MAX_USERDATA_ITEMS) + if (child_count >= MAX_EXTRADATA_ITEMS) return ERR_PTR(-ENOSPC); udm = kzalloc(sizeof(*udm), GFP_KERNEL); @@ -1120,11 +1120,11 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, int msg_len, int release_len) { - const char *userdata = NULL; + const char *extradata = NULL; const char *release; #ifdef CONFIG_NETCONSOLE_DYNAMIC - userdata = nt->userdata_complete; + extradata = nt->extradata_complete; #endif if (release_len) { @@ -1136,10 +1136,10 @@ static void send_msg_no_fragmentation(struct netconsole_target *nt, memcpy(nt->buf, msg, msg_len); } - if (userdata) + if (extradata) msg_len += scnprintf(&nt->buf[msg_len], MAX_PRINT_CHUNK - msg_len, - "%s", userdata); + "%s", extradata); send_udp(nt, nt->buf, msg_len); } @@ -1156,24 +1156,25 @@ static void send_fragmented_body(struct netconsole_target *nt, const char *msgbody, int header_len, int msgbody_len) { - const char *userdata = NULL; + int sent_extradata, preceding_bytes; + const char *extradata = NULL; int body_len, offset = 0; - int userdata_len = 0; + int extradata_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC - userdata = nt->userdata_complete; - userdata_len = nt->userdata_length; + extradata = nt->extradata_complete; + extradata_len = nt->userdata_length; #endif /* body_len represents the number of bytes that will be sent. This is * bigger than MAX_PRINT_CHUNK, thus, it will be split in multiple * packets */ - body_len = msgbody_len + userdata_len; + body_len = msgbody_len + extradata_len; /* In each iteration of the while loop below, we send a packet * containing the header and a portion of the body. The body is - * composed of two parts: msgbody and userdata. We keep track of how + * composed of two parts: msgbody and extradata. We keep track of how * many bytes have been sent so far using the offset variable, which * ranges from 0 to the total length of the body. */ @@ -1201,36 +1202,36 @@ static void send_fragmented_body(struct netconsole_target *nt, /* msgbody was finally written, either in the previous * messages and/or in the current buf. Time to write - * the userdata. + * the extradata. */ msgbody_written |= offset + this_offset >= msgbody_len; - /* Msg body is fully written and there is pending userdata to - * write, append userdata in this chunk + /* Msg body is fully written and there is pending extradata to + * write, append extradata in this chunk */ if (msgbody_written && offset + this_offset < body_len) { /* Track how much user data was already sent. First * time here, sent_userdata is zero */ - int sent_userdata = (offset + this_offset) - msgbody_len; + sent_extradata = (offset + this_offset) - msgbody_len; /* offset of bytes used in current buf */ - int preceding_bytes = this_chunk + this_header; + preceding_bytes = this_chunk + this_header; - if (WARN_ON_ONCE(sent_userdata < 0)) + if (WARN_ON_ONCE(sent_extradata < 0)) return; - this_chunk = min(userdata_len - sent_userdata, + this_chunk = min(extradata_len - sent_extradata, MAX_PRINT_CHUNK - preceding_bytes); if (WARN_ON_ONCE(this_chunk < 0)) /* this_chunk could be zero if all the previous * message used all the buffer. This is not a - * problem, userdata will be sent in the next + * problem, extradata will be sent in the next * iteration */ return; memcpy(nt->buf + this_header + this_offset, - userdata + sent_userdata, + extradata + sent_extradata, this_chunk); this_offset += this_chunk; } @@ -1287,17 +1288,17 @@ static void send_msg_fragmented(struct netconsole_target *nt, static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, int msg_len) { - int userdata_len = 0; + int extradata_len = 0; int release_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC - userdata_len = nt->userdata_length; + extradata_len = nt->userdata_length; #endif if (nt->release) release_len = strlen(init_utsname()->release) + 1; - if (msg_len + release_len + userdata_len <= MAX_PRINT_CHUNK) + if (msg_len + release_len + extradata_len <= MAX_PRINT_CHUNK) return send_msg_no_fragmentation(nt, msg, msg_len, release_len); return send_msg_fragmented(nt, msg, msg_len, release_len); From 563fe939a81ab08198b78dc8451ef3090969f30b Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:54 -0800 Subject: [PATCH 3/8] netconsole: Helper to count number of used entries Add a helper function nr_extradata_entries() to count the number of used extradata entries in a netconsole target. This refactors the duplicate code for counting entries into a single function, which will be reused by upcoming CPU sysdata changes. The helper uses list_count_nodes() to count the number of children in the userdata group configfs hierarchy. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/netconsole.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 7f05c7f74c31..15daaba65c88 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -662,6 +662,16 @@ out_unlock: return ret; } +/* Count number of entries we have in extradata. + * This is important because the extradata_complete only supports + * MAX_EXTRADATA_ITEMS entries. Before enabling any new {user,sys}data + * feature, number of entries needs to checked for available space. + */ +static size_t count_extradata_entries(struct netconsole_target *nt) +{ + return list_count_nodes(&nt->userdata_group.cg_children); +} + static ssize_t remote_mac_store(struct config_item *item, const char *buf, size_t count) { @@ -811,15 +821,13 @@ static struct config_item *userdatum_make_item(struct config_group *group, struct netconsole_target *nt; struct userdatum *udm; struct userdata *ud; - size_t child_count; if (strlen(name) > MAX_EXTRADATA_NAME_LEN) return ERR_PTR(-ENAMETOOLONG); ud = to_userdata(&group->cg_item); nt = userdata_to_target(ud); - child_count = list_count_nodes(&nt->userdata_group.cg_children); - if (child_count >= MAX_EXTRADATA_ITEMS) + if (count_extradata_entries(nt) >= MAX_EXTRADATA_ITEMS) return ERR_PTR(-ENOSPC); udm = kzalloc(sizeof(*udm), GFP_KERNEL); From 364f67837e86cfd59ef8727dbf6db15594281d4d Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:55 -0800 Subject: [PATCH 4/8] netconsole: Introduce configfs helpers for sysdata features This patch introduces a bitfield to store sysdata features in the netconsole_target struct. It also adds configfs helpers to enable or disable the CPU_NR feature, which populates the CPU number in sysdata. The patch provides the necessary infrastructure to set or unset the CPU_NR feature, but does not modify the message itself. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/netconsole.c | 81 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 15daaba65c88..710330ae8ee4 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -97,6 +97,15 @@ struct netconsole_target_stats { struct u64_stats_sync syncp; }; +/* Features enabled in sysdata. Contrary to userdata, this data is populated by + * the kernel. The fields are designed as bitwise flags, allowing multiple + * features to be set in sysdata_fields. + */ +enum sysdata_feature { + /* Populate the CPU that sends the message */ + CPU_NR = BIT(0), +}; + /** * struct netconsole_target - Represents a configured netconsole target. * @list: Links this target into the target_list. @@ -104,6 +113,7 @@ struct netconsole_target_stats { * @userdata_group: Links to the userdata configfs hierarchy * @extradata_complete: Cached, formatted string of append * @userdata_length: String length of usedata in extradata_complete. + * @sysdata_fields: Sysdata features enabled. * @stats: Packet send stats for the target. Used for debugging. * @enabled: On / off knob to enable / disable target. * Visible from userspace (read-write). @@ -132,6 +142,8 @@ struct netconsole_target { struct config_group userdata_group; char extradata_complete[MAX_EXTRADATA_ENTRY_LEN * MAX_EXTRADATA_ITEMS]; size_t userdata_length; + /* bit-wise with sysdata_feature bits */ + u32 sysdata_fields; #endif struct netconsole_target_stats stats; bool enabled; @@ -399,6 +411,19 @@ static ssize_t transmit_errors_show(struct config_item *item, char *buf) return sysfs_emit(buf, "%llu\n", xmit_drop_count + enomem_count); } +/* configfs helper to display if cpu_nr sysdata feature is enabled */ +static ssize_t sysdata_cpu_nr_enabled_show(struct config_item *item, char *buf) +{ + struct netconsole_target *nt = to_target(item->ci_parent); + bool cpu_nr_enabled; + + mutex_lock(&dynamic_netconsole_mutex); + cpu_nr_enabled = !!(nt->sysdata_fields & CPU_NR); + mutex_unlock(&dynamic_netconsole_mutex); + + return sysfs_emit(buf, "%d\n", cpu_nr_enabled); +} + /* * This one is special -- targets created through the configfs interface * are not enabled (and the corresponding netpoll activated) by default. @@ -793,7 +818,62 @@ out_unlock: return ret; } +/* disable_sysdata_feature - Disable sysdata feature and clean sysdata + * @nt: target that is disabling the feature + * @feature: feature being disabled + */ +static void disable_sysdata_feature(struct netconsole_target *nt, + enum sysdata_feature feature) +{ + nt->sysdata_fields &= ~feature; + nt->extradata_complete[nt->userdata_length] = 0; +} + +/* configfs helper to sysdata cpu_nr feature */ +static ssize_t sysdata_cpu_nr_enabled_store(struct config_item *item, + const char *buf, size_t count) +{ + struct netconsole_target *nt = to_target(item->ci_parent); + bool cpu_nr_enabled, curr; + ssize_t ret; + + ret = kstrtobool(buf, &cpu_nr_enabled); + if (ret) + return ret; + + mutex_lock(&dynamic_netconsole_mutex); + curr = nt->sysdata_fields & CPU_NR; + if (cpu_nr_enabled == curr) + /* no change requested */ + goto unlock_ok; + + if (cpu_nr_enabled && + count_extradata_entries(nt) >= MAX_EXTRADATA_ITEMS) { + /* user wants the new feature, but there is no space in the + * buffer. + */ + ret = -ENOSPC; + goto unlock; + } + + if (cpu_nr_enabled) + nt->sysdata_fields |= CPU_NR; + else + /* This is special because extradata_complete might have + * remaining data from previous sysdata, and it needs to be + * cleaned. + */ + disable_sysdata_feature(nt, CPU_NR); + +unlock_ok: + ret = strnlen(buf, count); +unlock: + mutex_unlock(&dynamic_netconsole_mutex); + return ret; +} + CONFIGFS_ATTR(userdatum_, value); +CONFIGFS_ATTR(sysdata_, cpu_nr_enabled); static struct configfs_attribute *userdatum_attrs[] = { &userdatum_attr_value, @@ -853,6 +933,7 @@ static void userdatum_drop(struct config_group *group, struct config_item *item) } static struct configfs_attribute *userdata_attrs[] = { + &sysdata_attr_cpu_nr_enabled, NULL, }; From 2bae25b16aea249f0e96757b6cd28b03d2b4397f Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:56 -0800 Subject: [PATCH 5/8] netconsole: Include sysdata in extradata entry count Modify count_extradata_entries() to include sysdata fields when calculating the total number of extradata entries. This change ensures that the sysdata feature, specifically the CPU number field, is correctly counted against the MAX_EXTRADATA_ITEMS limit. The modification adds a simple check for the CPU_NR flag in the sysdata_fields, incrementing the entry count accordingly. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/netconsole.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 710330ae8ee4..50739c7dbfb6 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -694,7 +694,15 @@ out_unlock: */ static size_t count_extradata_entries(struct netconsole_target *nt) { - return list_count_nodes(&nt->userdata_group.cg_children); + size_t entries; + + /* Userdata entries */ + entries = list_count_nodes(&nt->userdata_group.cg_children); + /* Plus sysdata entries */ + if (nt->sysdata_fields & CPU_NR) + entries += 1; + + return entries; } static ssize_t remote_mac_store(struct config_item *item, const char *buf, From ec15bc46c63cc21bba4c4071060797a4b51f50de Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:57 -0800 Subject: [PATCH 6/8] netconsole: add support for sysdata and CPU population Add infrastructure to automatically append kernel-generated data (sysdata) to netconsole messages. As the first use case, implement CPU number population, which adds the CPU that sent the message. This change introduces three distinct data types: - extradata: The complete set of appended data (sysdata + userdata) - userdata: User-provided key-value pairs from userspace - sysdata: Kernel-populated data (e.g. cpu=XX) The implementation adds a new configfs attribute 'cpu_nr' to control CPU number population per target. When enabled, each message is tagged with its originating CPU. The sysdata is dynamically updated at message time and appended after any existing userdata. The CPU number is formatted as "cpu=XX" and is added to the extradata buffer, respecting the existing size limits. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- drivers/net/netconsole.c | 53 ++++++++++++++++++++++++++++++++-------- 1 file changed, 43 insertions(+), 10 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 50739c7dbfb6..f77eddf22185 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -1117,6 +1117,40 @@ static void populate_configfs_item(struct netconsole_target *nt, init_target_config_group(nt, target_name); } +/* + * prepare_extradata - append sysdata at extradata_complete in runtime + * @nt: target to send message to + */ +static int prepare_extradata(struct netconsole_target *nt) +{ + int sysdata_len, extradata_len; + + /* userdata was appended when configfs write helper was called + * by update_userdata(). + */ + extradata_len = nt->userdata_length; + + if (!(nt->sysdata_fields & CPU_NR)) + goto out; + + /* Append cpu=%d at extradata_complete after userdata str */ + sysdata_len = scnprintf(&nt->extradata_complete[nt->userdata_length], + MAX_EXTRADATA_ENTRY_LEN, " cpu=%u\n", + raw_smp_processor_id()); + + extradata_len += sysdata_len; + + WARN_ON_ONCE(extradata_len > + MAX_EXTRADATA_ENTRY_LEN * MAX_EXTRADATA_ITEMS); + +out: + return extradata_len; +} +#else /* CONFIG_NETCONSOLE_DYNAMIC not set */ +static int prepare_extradata(struct netconsole_target *nt) +{ + return 0; +} #endif /* CONFIG_NETCONSOLE_DYNAMIC */ /* Handle network interface device notifications */ @@ -1251,16 +1285,14 @@ static void append_release(char *buf) static void send_fragmented_body(struct netconsole_target *nt, const char *msgbody, int header_len, - int msgbody_len) + int msgbody_len, int extradata_len) { int sent_extradata, preceding_bytes; const char *extradata = NULL; int body_len, offset = 0; - int extradata_len = 0; #ifdef CONFIG_NETCONSOLE_DYNAMIC extradata = nt->extradata_complete; - extradata_len = nt->userdata_length; #endif /* body_len represents the number of bytes that will be sent. This is @@ -1341,7 +1373,8 @@ static void send_fragmented_body(struct netconsole_target *nt, static void send_msg_fragmented(struct netconsole_target *nt, const char *msg, int msg_len, - int release_len) + int release_len, + int extradata_len) { int header_len, msgbody_len; const char *msgbody; @@ -1369,7 +1402,8 @@ static void send_msg_fragmented(struct netconsole_target *nt, /* for now on, the header will be persisted, and the msgbody * will be replaced */ - send_fragmented_body(nt, msgbody, header_len, msgbody_len); + send_fragmented_body(nt, msgbody, header_len, msgbody_len, + extradata_len); } /** @@ -1385,12 +1419,10 @@ static void send_msg_fragmented(struct netconsole_target *nt, static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, int msg_len) { - int extradata_len = 0; int release_len = 0; + int extradata_len; -#ifdef CONFIG_NETCONSOLE_DYNAMIC - extradata_len = nt->userdata_length; -#endif + extradata_len = prepare_extradata(nt); if (nt->release) release_len = strlen(init_utsname()->release) + 1; @@ -1398,7 +1430,8 @@ static void send_ext_msg_udp(struct netconsole_target *nt, const char *msg, if (msg_len + release_len + extradata_len <= MAX_PRINT_CHUNK) return send_msg_no_fragmentation(nt, msg, msg_len, release_len); - return send_msg_fragmented(nt, msg, msg_len, release_len); + return send_msg_fragmented(nt, msg, msg_len, release_len, + extradata_len); } static void write_ext_msg(struct console *con, const char *msg, From 12fd83ca44d8c4b0a78beab8178a1a6754eae1b3 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:58 -0800 Subject: [PATCH 7/8] netconsole: selftest: test for sysdata CPU Add a new selftest to verify that the netconsole module correctly handles CPU runtime data in sysdata. The test validates three scenarios: 1. Basic CPU sysdata functionality - verifies that cpu=X is appended to messages 2. CPU sysdata with userdata - ensures CPU data works alongside userdata 3. Disabled CPU sysdata - confirms no CPU data is included when disabled The test uses taskset to control which CPU sends messages and verifies the reported CPU matches the one used. This helps ensure that netconsole accurately tracks and reports the originating CPU of messages. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- tools/testing/selftests/drivers/net/Makefile | 1 + .../drivers/net/lib/sh/lib_netcons.sh | 17 ++ .../selftests/drivers/net/netcons_sysdata.sh | 167 ++++++++++++++++++ 3 files changed, 185 insertions(+) create mode 100755 tools/testing/selftests/drivers/net/netcons_sysdata.sh diff --git a/tools/testing/selftests/drivers/net/Makefile b/tools/testing/selftests/drivers/net/Makefile index c7f1c443f2af..28b6d47f812d 100644 --- a/tools/testing/selftests/drivers/net/Makefile +++ b/tools/testing/selftests/drivers/net/Makefile @@ -9,6 +9,7 @@ TEST_PROGS := \ netcons_basic.sh \ netcons_fragmented_msg.sh \ netcons_overflow.sh \ + netcons_sysdata.sh \ ping.py \ queues.py \ stats.py \ diff --git a/tools/testing/selftests/drivers/net/lib/sh/lib_netcons.sh b/tools/testing/selftests/drivers/net/lib/sh/lib_netcons.sh index 0c262b123fdd..3c96b022954d 100644 --- a/tools/testing/selftests/drivers/net/lib/sh/lib_netcons.sh +++ b/tools/testing/selftests/drivers/net/lib/sh/lib_netcons.sh @@ -230,3 +230,20 @@ function check_for_dependencies() { exit "${ksft_skip}" fi } + +function check_for_taskset() { + if ! which taskset > /dev/null ; then + echo "SKIP: taskset(1) is not available" >&2 + exit "${ksft_skip}" + fi +} + +# This is necessary if running multiple tests in a row +function pkill_socat() { + PROCESS_NAME="socat UDP-LISTEN:6666,fork ${OUTPUT_FILE}" + # socat runs under timeout(1), kill it if it is still alive + # do not fail if socat doesn't exist anymore + set +e + pkill -f "${PROCESS_NAME}" + set -e +} diff --git a/tools/testing/selftests/drivers/net/netcons_sysdata.sh b/tools/testing/selftests/drivers/net/netcons_sysdata.sh new file mode 100755 index 000000000000..2b78fd1f5982 --- /dev/null +++ b/tools/testing/selftests/drivers/net/netcons_sysdata.sh @@ -0,0 +1,167 @@ +#!/usr/bin/env bash +# SPDX-License-Identifier: GPL-2.0 + +# A test that makes sure that sysdata runtime CPU data is properly set +# when a message is sent. +# +# There are 3 different tests, every time sent using a random CPU. +# - Test #1 +# * Only enable cpu_nr sysdata feature. +# - Test #2 +# * Keep cpu_nr sysdata feature enable and enable userdata. +# - Test #3 +# * keep userdata enabled, and disable sysdata cpu_nr feature. +# +# Author: Breno Leitao + +set -euo pipefail + +SCRIPTDIR=$(dirname "$(readlink -e "${BASH_SOURCE[0]}")") + +source "${SCRIPTDIR}"/lib/sh/lib_netcons.sh + +# Enable the sysdata cpu_nr feature +function set_cpu_nr() { + if [[ ! -f "${NETCONS_PATH}/userdata/cpu_nr_enabled" ]] + then + echo "Populate CPU configfs path not available in ${NETCONS_PATH}/userdata/cpu_nr_enabled" >&2 + exit "${ksft_skip}" + fi + + echo 1 > "${NETCONS_PATH}/userdata/cpu_nr_enabled" +} + +# Disable the sysdata cpu_nr feature +function unset_cpu_nr() { + echo 0 > "${NETCONS_PATH}/userdata/cpu_nr_enabled" +} + +# Test if MSG content and `cpu=${CPU}` exists in OUTPUT_FILE +function validate_sysdata_cpu_exists() { + # OUTPUT_FILE will contain something like: + # 6.11.1-0_fbk0_rc13_509_g30d75cea12f7,13,1822,115075213798,-;netconsole selftest: netcons_gtJHM + # userdatakey=userdatavalue + # cpu=X + + if [ ! -f "$OUTPUT_FILE" ]; then + echo "FAIL: File was not generated." >&2 + exit "${ksft_fail}" + fi + + if ! grep -q "${MSG}" "${OUTPUT_FILE}"; then + echo "FAIL: ${MSG} not found in ${OUTPUT_FILE}" >&2 + cat "${OUTPUT_FILE}" >&2 + exit "${ksft_fail}" + fi + + # Check if cpu=XX exists in the file and matches the one used + # in taskset(1) + if ! grep -q "cpu=${CPU}\+" "${OUTPUT_FILE}"; then + echo "FAIL: 'cpu=${CPU}' not found in ${OUTPUT_FILE}" >&2 + cat "${OUTPUT_FILE}" >&2 + exit "${ksft_fail}" + fi + + rm "${OUTPUT_FILE}" + pkill_socat +} + +# Test if MSG content exists in OUTPUT_FILE but no `cpu=` string +function validate_sysdata_no_cpu() { + if [ ! -f "$OUTPUT_FILE" ]; then + echo "FAIL: File was not generated." >&2 + exit "${ksft_fail}" + fi + + if ! grep -q "${MSG}" "${OUTPUT_FILE}"; then + echo "FAIL: ${MSG} not found in ${OUTPUT_FILE}" >&2 + cat "${OUTPUT_FILE}" >&2 + exit "${ksft_fail}" + fi + + if grep -q "cpu=" "${OUTPUT_FILE}"; then + echo "FAIL: 'cpu= found in ${OUTPUT_FILE}" >&2 + cat "${OUTPUT_FILE}" >&2 + exit "${ksft_fail}" + fi + + rm "${OUTPUT_FILE}" +} + +# Start socat, send the message and wait for the file to show up in the file +# system +function runtest { + # Listen for netconsole port inside the namespace and destination + # interface + listen_port_and_save_to "${OUTPUT_FILE}" & + # Wait for socat to start and listen to the port. + wait_local_port_listen "${NAMESPACE}" "${PORT}" udp + # Send the message + taskset -c "${CPU}" echo "${MSG}: ${TARGET}" > /dev/kmsg + # Wait until socat saves the file to disk + busywait "${BUSYWAIT_TIMEOUT}" test -s "${OUTPUT_FILE}" +} + +# ========== # +# Start here # +# ========== # + +modprobe netdevsim 2> /dev/null || true +modprobe netconsole 2> /dev/null || true + +# Check for basic system dependency and exit if not found +check_for_dependencies +# This test also depends on taskset(1). Check for it before starting the test +check_for_taskset + +# Set current loglevel to KERN_INFO(6), and default to KERN_NOTICE(5) +echo "6 5" > /proc/sys/kernel/printk +# Remove the namespace, interfaces and netconsole target on exit +trap cleanup EXIT +# Create one namespace and two interfaces +set_network +# Create a dynamic target for netconsole +create_dynamic_target + +#==================================================== +# TEST #1 +# Send message from a random CPU +#==================================================== +# Random CPU in the system +CPU=$((RANDOM % $(nproc))) +OUTPUT_FILE="/tmp/${TARGET}_1" +MSG="Test #1 from CPU${CPU}" +# Enable the auto population of cpu_nr +set_cpu_nr +runtest +# Make sure the message was received in the dst part +# and exit +validate_sysdata_cpu_exists + +#==================================================== +# TEST #2 +# This test now adds userdata together with sysdata +# =================================================== +# Get a new random CPU +CPU=$((RANDOM % $(nproc))) +OUTPUT_FILE="/tmp/${TARGET}_2" +MSG="Test #2 from CPU${CPU}" +set_user_data +runtest +validate_sysdata_cpu_exists + +# =================================================== +# TEST #3 +# Unset cpu_nr, so, no CPU should be appended. +# userdata is still set +# =================================================== +CPU=$((RANDOM % $(nproc))) +OUTPUT_FILE="/tmp/${TARGET}_3" +MSG="Test #3 from CPU${CPU}" +# Enable the auto population of cpu_nr +unset_cpu_nr +runtest +# At this time, cpu= shouldn't be present in the msg +validate_sysdata_no_cpu + +exit "${ksft_pass}" From a7aec70a9092aec61a29ad1e1fc387ef888a6ad6 Mon Sep 17 00:00:00 2001 From: Breno Leitao Date: Thu, 6 Feb 2025 03:05:59 -0800 Subject: [PATCH 8/8] netconsole: docs: Add documentation for CPU number auto-population Update the netconsole documentation to explain the new feature that allows automatic population of the CPU number. The key changes include introducing a new section titled "CPU number auto population in userdata", explaining how to enable the CPU number auto-population feature by writing to the "populate_cpu_nr" file in the netconsole configfs hierarchy. This documentation update ensures users are aware of the new CPU number auto-population functionality and how to leverage it for better demultiplexing and visibility of parallel netconsole output. Signed-off-by: Breno Leitao Reviewed-by: Simon Horman Signed-off-by: David S. Miller --- Documentation/networking/netconsole.rst | 45 +++++++++++++++++++++++++ 1 file changed, 45 insertions(+) diff --git a/Documentation/networking/netconsole.rst b/Documentation/networking/netconsole.rst index 94c4680fdf3e..84803c59968a 100644 --- a/Documentation/networking/netconsole.rst +++ b/Documentation/networking/netconsole.rst @@ -17,6 +17,8 @@ Release prepend support by Breno Leitao , Jul 7 2023 Userdata append support by Matthew Wood , Jan 22 2024 +Sysdata append support by Breno Leitao , Jan 15 2025 + Please send bug reports to Matt Mackall Satyam Sharma , and Cong Wang @@ -238,6 +240,49 @@ Delete `userdata` entries with `rmdir`:: It is recommended to not write user data values with newlines. +CPU number auto population in userdata +-------------------------------------- + +Inside the netconsole configfs hierarchy, there is a file called +`cpu_nr` under the `userdata` directory. This file is used to enable or disable +the automatic CPU number population feature. This feature automatically +populates the CPU number that is sending the message. + +To enable the CPU number auto-population:: + + echo 1 > /sys/kernel/config/netconsole/target1/userdata/cpu_nr + +When this option is enabled, the netconsole messages will include an additional +line in the userdata field with the format `cpu=`. This allows the +receiver of the netconsole messages to easily differentiate and demultiplex +messages originating from different CPUs, which is particularly useful when +dealing with parallel log output. + +Example:: + + echo "This is a message" > /dev/kmsg + 12,607,22085407756,-;This is a message + cpu=42 + +In this example, the message was sent by CPU 42. + +.. note:: + + If the user has set a conflicting `cpu` key in the userdata dictionary, + both keys will be reported, with the kernel-populated entry appearing after + the user one. For example:: + + # User-defined CPU entry + mkdir -p /sys/kernel/config/netconsole/target1/userdata/cpu + echo "1" > /sys/kernel/config/netconsole/target1/userdata/cpu/value + + Output might look like:: + + 12,607,22085407756,-;This is a message + cpu=1 + cpu=42 # kernel-populated value + + Extended console: =================