diff options
author | John Ogness <john.ogness@linutronix.de> | 2023-09-20 18:52:38 +0300 |
---|---|---|
committer | Petr Mladek <pmladek@suse.com> | 2023-09-21 17:52:10 +0300 |
commit | 98a0465531a5982dd897fd81222a5d3465999951 (patch) | |
tree | 109733b7230f4829214ccc20c6d52929fe310577 /kernel/printk/printk.c | |
parent | 9757acd0a700ba4a0d16dde4ba820eb052aba1a7 (diff) | |
download | linux-98a0465531a5982dd897fd81222a5d3465999951.tar.xz |
printk: fix illegal pbufs access for !CONFIG_PRINTK
When CONFIG_PRINTK is not set, PRINTK_MESSAGE_MAX is 0. This
leads to a zero-sized array @outbuf in @printk_shared_pbufs. In
console_flush_all() a pointer to the first element of the array
is assigned with:
char *outbuf = &printk_shared_pbufs.outbuf[0];
For !CONFIG_PRINTK this leads to a compiler warning:
warning: array subscript 0 is outside array bounds of
'char[0]' [-Warray-bounds]
This is not really dangerous because printk_get_next_message()
always returns false for !CONFIG_PRINTK, which leads to @outbuf
never being used. However, it makes no sense to even compile
these functions for !CONFIG_PRINTK.
Extend the existing '#ifdef CONFIG_PRINTK' block to contain
the formatting and emitting functions since these have no
purpose in !CONFIG_PRINTK. This also allows removing several
more !CONFIG_PRINTK dummies as well as moving
@suppress_panic_printk into a CONFIG_PRINTK block.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202309201724.M9BMAQIh-lkp@intel.com/
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20230920155238.670439-1-john.ogness@linutronix.de
Diffstat (limited to 'kernel/printk/printk.c')
-rw-r--r-- | kernel/printk/printk.c | 44 |
1 files changed, 18 insertions, 26 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 778359b21761..7f40d9122caa 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -102,12 +102,6 @@ DEFINE_STATIC_SRCU(console_srcu); */ int __read_mostly suppress_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; - #ifdef CONFIG_LOCKDEP static struct lockdep_map console_lock_dep_map = { .name = "console_lock" @@ -445,6 +439,12 @@ 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 */ @@ -2346,22 +2346,6 @@ static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progre static u64 syslog_seq; -static size_t record_print_text(const struct printk_record *r, - bool syslog, bool time) -{ - return 0; -} -static ssize_t info_print_ext_header(char *buf, size_t size, - struct printk_info *info) -{ - return 0; -} -static ssize_t msg_print_ext_body(char *buf, size_t size, - char *text, size_t text_len, - struct dev_printk_info *dev_info) { return 0; } -static void console_lock_spinning_enable(void) { } -static int console_lock_spinning_disable_and_check(int cookie) { return 0; } -static bool suppress_message_printing(int level) { return false; } static bool pr_flush(int timeout_ms, bool reset_on_progress) { return true; } static bool __pr_flush(struct console *con, int timeout_ms, bool reset_on_progress) { return true; } @@ -2715,6 +2699,8 @@ static void __console_unlock(void) up_console_sem(); } +#ifdef CONFIG_PRINTK + /* * Prepend the message in @pmsg->pbufs->outbuf with a "dropped message". This * is achieved by shifting the existing message over and inserting the dropped @@ -2729,7 +2715,6 @@ static void __console_unlock(void) * * If @pmsg->pbufs->outbuf is modified, @pmsg->outbuf_len is updated. */ -#ifdef CONFIG_PRINTK void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) { struct printk_buffers *pbufs = pmsg->pbufs; @@ -2761,9 +2746,6 @@ void console_prepend_dropped(struct printk_message *pmsg, unsigned long dropped) memcpy(outbuf, scratchbuf, len); pmsg->outbuf_len += len; } -#else -#define console_prepend_dropped(pmsg, dropped) -#endif /* CONFIG_PRINTK */ /* * Read and format the specified record (or a later record if the specified @@ -2921,6 +2903,16 @@ skip: return true; } +#else + +static bool console_emit_next_record(struct console *con, bool *handover, int cookie) +{ + *handover = false; + return false; +} + +#endif /* CONFIG_PRINTK */ + /* * Print out all remaining records to all consoles. * |