From 34996e42f82bfd60bc2c191e5cae3c6ab233ec6c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 7 Aug 2024 15:11:27 +0200 Subject: Merging upstream version 6.9.7. Signed-off-by: Daniel Baumann --- kernel/printk/printk.c | 41 ++++++++------------------------------- kernel/printk/printk_ringbuffer.c | 20 +++++++++++++++---- kernel/printk/printk_ringbuffer.h | 16 ++++++++++++++- 3 files changed, 39 insertions(+), 38 deletions(-) (limited to 'kernel/printk') diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index e1b992652a..adf99c05ad 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -34,7 +34,7 @@ #include #include #include -#include +#include #include #include #include @@ -462,12 +462,6 @@ static int console_msg_format = MSG_FORMAT_DEFAULT; static DEFINE_MUTEX(syslog_lock); #ifdef CONFIG_PRINTK -/* - * During panic, heavy printk by other CPUs can delay the - * panic and risk deadlock on console resources. - */ -static int __read_mostly suppress_panic_printk; - DECLARE_WAIT_QUEUE_HEAD(log_wait); /* All 3 protected by @syslog_lock. */ /* the next printk record to read by syslog(READ) or /proc/kmsg */ @@ -621,17 +615,6 @@ static int check_syslog_permissions(int type, int source) if (syslog_action_restricted(type)) { if (capable(CAP_SYSLOG)) goto ok; - /* - * For historical reasons, accept CAP_SYS_ADMIN too, with - * a warning. - */ - if (capable(CAP_SYS_ADMIN)) { - pr_warn_once("%s (%d): Attempt to access syslog with " - "CAP_SYS_ADMIN but no CAP_SYSLOG " - "(deprecated).\n", - current->comm, task_pid_nr(current)); - goto ok; - } return -EPERM; } ok: @@ -974,7 +957,7 @@ const struct file_operations kmsg_fops = { .release = devkmsg_release, }; -#ifdef CONFIG_CRASH_CORE +#ifdef CONFIG_VMCORE_INFO /* * This appends the listed symbols to /proc/vmcore * @@ -2328,7 +2311,12 @@ asmlinkage int vprintk_emit(int facility, int level, if (unlikely(suppress_printk)) return 0; - if (unlikely(suppress_panic_printk) && other_cpu_in_panic()) + /* + * The messages on the panic CPU are the most important. If + * non-panic CPUs are generating any messages, they will be + * silently dropped. + */ + if (other_cpu_in_panic()) return 0; if (level == LOGLEVEL_SCHED) { @@ -2813,8 +2801,6 @@ void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) bool printk_get_next_message(struct printk_message *pmsg, u64 seq, bool is_extended, bool may_suppress) { - static int panic_console_dropped; - struct printk_buffers *pbufs = pmsg->pbufs; const size_t scratchbuf_sz = sizeof(pbufs->scratchbuf); const size_t outbuf_sz = sizeof(pbufs->outbuf); @@ -2842,17 +2828,6 @@ bool printk_get_next_message(struct printk_message *pmsg, u64 seq, pmsg->seq = r.info->seq; pmsg->dropped = r.info->seq - seq; - /* - * Check for dropped messages in panic here so that printk - * suppression can occur as early as possible if necessary. - */ - if (pmsg->dropped && - panic_in_progress() && - panic_console_dropped++ > 10) { - suppress_panic_printk = 1; - pr_warn_once("Too many dropped messages. Suppress messages on non-panic CPUs to prevent livelock.\n"); - } - /* Skip record that has level above the console loglevel. */ if (may_suppress && suppress_message_printing(r.info->level)) goto out; diff --git a/kernel/printk/printk_ringbuffer.c b/kernel/printk/printk_ringbuffer.c index f5a8bb606f..88e8f3a619 100644 --- a/kernel/printk/printk_ringbuffer.c +++ b/kernel/printk/printk_ringbuffer.c @@ -1034,9 +1034,13 @@ static char *data_alloc(struct printk_ringbuffer *rb, unsigned int size, unsigned long next_lpos; if (size == 0) { - /* Specify a data-less block. */ - blk_lpos->begin = NO_LPOS; - blk_lpos->next = NO_LPOS; + /* + * Data blocks are not created for empty lines. Instead, the + * reader will recognize these special lpos values and handle + * it appropriately. + */ + blk_lpos->begin = EMPTY_LINE_LPOS; + blk_lpos->next = EMPTY_LINE_LPOS; return NULL; } @@ -1214,10 +1218,18 @@ static const char *get_data(struct prb_data_ring *data_ring, /* Data-less data block description. */ if (BLK_DATALESS(blk_lpos)) { - if (blk_lpos->begin == NO_LPOS && blk_lpos->next == NO_LPOS) { + /* + * Records that are just empty lines are also valid, even + * though they do not have a data block. For such records + * explicitly return empty string data to signify success. + */ + if (blk_lpos->begin == EMPTY_LINE_LPOS && + blk_lpos->next == EMPTY_LINE_LPOS) { *data_size = 0; return ""; } + + /* Data lost, invalid, or otherwise unavailable. */ return NULL; } diff --git a/kernel/printk/printk_ringbuffer.h b/kernel/printk/printk_ringbuffer.h index cb887489d0..52626d0f1f 100644 --- a/kernel/printk/printk_ringbuffer.h +++ b/kernel/printk/printk_ringbuffer.h @@ -127,8 +127,22 @@ enum desc_state { #define DESC_SV(id, state) (((unsigned long)state << DESC_FLAGS_SHIFT) | id) #define DESC_ID_MASK (~DESC_FLAGS_MASK) #define DESC_ID(sv) ((sv) & DESC_ID_MASK) + +/* + * Special data block logical position values (for fields of + * @prb_desc.text_blk_lpos). + * + * - Bit0 is used to identify if the record has no data block. (Implemented in + * the LPOS_DATALESS() macro.) + * + * - Bit1 specifies the reason for not having a data block. + * + * These special values could never be real lpos values because of the + * meta data and alignment padding of data blocks. (See to_blk_size() for + * details.) + */ #define FAILED_LPOS 0x1 -#define NO_LPOS 0x3 +#define EMPTY_LINE_LPOS 0x3 #define FAILED_BLK_LPOS \ { \ -- cgit v1.2.3