printk changes for 5.18
-----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEESH4wyp42V4tXvYsjUqAMR0iAlPIFAmI4ggsACgkQUqAMR0iA lPLrlA//R12HGCGSzdpdyynl+5wByIqcHe8RANHOAj9f9qxBtmYv2ZK69mzSvhHO 6kAGdb3vBtxo1NCHeqxlXpds9GP/zOGEWmEJP2P7pIZ8ci8QtwrXCtQ8XIW9UGhJ WHzXpXkfzcIDsRZs6B1pxN5cRXuW2VVzfgxyu6L+hvNV0o0PPO4A48ptzNBZh8rj URAid+n/aGs9SOXM0h8SRjjBYEqjiB2RZ3gLg5XGZmcATtitBO135LGZnBR2fwnX RZKckbdA/fBzqS4Njsp2rV5Rqldwj7mHzQbcsQm4YDrxSdl8d78XxQdAA5sNyaCD ToDw6/DeegXzgtPJpuBH/ymF9RczIu4l3eawO1FBMCB5EPq56zVHWErxry8qaTgi yQFqhBgifNN5NqfQCn7dyF10usmsvImFczre7ZxJvL7vmzqDsYYqdZG5oouLudR4 iOphFwX71v4X+RsxbOXqEt+mS3AwqEJc1SZl5rrDc4TSUOE1qCd+ncLTAuAf3Wfm 1xaZ+siomahcZAKrgmSw6AcD5bU+JJpr6FktKAddiO7J1+nIdT1lYEbpUsfWZ/p8 Kx8A2M2ula+whJ6CgtnGTsbsacsFi+j/MioMTGZIU+Fubkig3XEeIp3QUO6sEN+9 /sUQ6Wj6c95miWdttff9o6ap8py9NbfuKIw/HMOesfLVKP82rmw= =EUpJ -----END PGP SIGNATURE----- Merge tag 'printk-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux Pull printk updates from Petr Mladek: - Make %pK behave the same as %p for kptr_restrict == 0 also with no_hash_pointers parameter - Ignore the default console in the device tree also when console=null or console="" is used on the command line - Document console=null and console="" behavior - Prevent a deadlock and a livelock caused by console_lock in panic() - Make console_lock available for panicking CPU - Fast query for the next to-be-used sequence number - Use the expected return values in printk.devkmsg __setup handler - Use the correct atomic operations in wake_up_klogd() irq_work handler - Avoid possible unaligned access when handling %4cc printing format * tag 'printk-for-5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux: printk: fix return value of printk.devkmsg __setup handler vsprintf: Fix %pK with kptr_restrict == 0 printk: make suppress_panic_printk static printk: Set console_set_on_cmdline=1 when __add_preferred_console() is called with user_specified == true Docs: printk: add 'console=null|""' to admin/kernel-parameters printk: use atomic updates for klogd work printk: Drop console_sem during panic printk: Avoid livelock with heavy printk during panic printk: disable optimistic spin during panic printk: Add panic_in_progress helper vsprintf: Move space out of string literals in fourcc_string() vsprintf: Fix potential unaligned access printk: ringbuffer: Improve prb_next_seq() performance
This commit is contained in:
Linus Torvalds
commit
3ef4ea3d84
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@ -724,6 +724,12 @@
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hvc<n> Use the hypervisor console device <n>. This is for
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both Xen and PowerPC hypervisors.
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{ null | "" }
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Use to disable console output, i.e., to have kernel
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console messages discarded.
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This must be the only console= parameter used on the
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kernel command line.
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If the device connected to the port is not a TTY but a braille
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device, prepend "brl," before the device type, for instance
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console=brl,ttyS0
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@ -3516,8 +3522,7 @@
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difficult since unequal pointers can no longer be
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compared. However, if this command-line option is
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specified, then all normal pointers will have their true
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value printed. Pointers printed via %pK may still be
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hashed. This option should only be specified when
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value printed. This option should only be specified when
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debugging the kernel. Please do not use on production
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kernels.
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@ -93,6 +93,12 @@ EXPORT_SYMBOL_GPL(console_drivers);
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*/
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int __read_mostly suppress_printk;
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/*
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* During panic, heavy printk by other CPUs can delay the
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* panic and risk deadlock on console resources.
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*/
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static int __read_mostly suppress_panic_printk;
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#ifdef CONFIG_LOCKDEP
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static struct lockdep_map console_lock_dep_map = {
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.name = "console_lock"
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@ -146,8 +152,10 @@ static int __control_devkmsg(char *str)
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static int __init control_devkmsg(char *str)
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{
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if (__control_devkmsg(str) < 0)
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if (__control_devkmsg(str) < 0) {
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pr_warn("printk.devkmsg: bad option string '%s'\n", str);
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return 1;
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}
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/*
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* Set sysctl string accordingly:
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@ -166,7 +174,7 @@ static int __init control_devkmsg(char *str)
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*/
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devkmsg_log |= DEVKMSG_LOG_MASK_LOCK;
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return 0;
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return 1;
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}
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__setup("printk.devkmsg=", control_devkmsg);
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@ -257,6 +265,11 @@ static void __up_console_sem(unsigned long ip)
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}
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#define up_console_sem() __up_console_sem(_RET_IP_)
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static bool panic_in_progress(void)
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{
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return unlikely(atomic_read(&panic_cpu) != PANIC_CPU_INVALID);
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}
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/*
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* This is used for debugging the mess that is the VT code by
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* keeping track if we have the console semaphore held. It's
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@ -1843,6 +1856,16 @@ static int console_trylock_spinning(void)
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if (console_trylock())
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return 1;
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/*
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* It's unsafe to spin once a panic has begun. If we are the
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* panic CPU, we may have already halted the owner of the
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* console_sem. If we are not the panic CPU, then we should
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* avoid taking console_sem, so the panic CPU has a better
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* chance of cleanly acquiring it later.
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*/
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if (panic_in_progress())
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return 0;
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printk_safe_enter_irqsave(flags);
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raw_spin_lock(&console_owner_lock);
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@ -2218,6 +2241,10 @@ asmlinkage int vprintk_emit(int facility, int level,
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if (unlikely(suppress_printk))
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return 0;
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if (unlikely(suppress_panic_printk) &&
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atomic_read(&panic_cpu) != raw_smp_processor_id())
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return 0;
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if (level == LOGLEVEL_SCHED) {
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level = LOGLEVEL_DEFAULT;
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in_sched = true;
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@ -2324,6 +2351,20 @@ asmlinkage __visible void early_printk(const char *fmt, ...)
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}
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#endif
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static void set_user_specified(struct console_cmdline *c, bool user_specified)
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{
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if (!user_specified)
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return;
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/*
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* @c console was defined by the user on the command line.
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* Do not clear when added twice also by SPCR or the device tree.
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*/
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c->user_specified = true;
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/* At least one console defined by the user on the command line. */
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console_set_on_cmdline = 1;
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}
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static int __add_preferred_console(char *name, int idx, char *options,
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char *brl_options, bool user_specified)
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{
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@ -2340,8 +2381,7 @@ static int __add_preferred_console(char *name, int idx, char *options,
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if (strcmp(c->name, name) == 0 && c->index == idx) {
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if (!brl_options)
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preferred_console = i;
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if (user_specified)
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c->user_specified = true;
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set_user_specified(c, user_specified);
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return 0;
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}
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}
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@ -2351,7 +2391,7 @@ static int __add_preferred_console(char *name, int idx, char *options,
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preferred_console = i;
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strlcpy(c->name, name, sizeof(c->name));
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c->options = options;
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c->user_specified = user_specified;
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set_user_specified(c, user_specified);
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braille_set_options(c, brl_options);
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c->index = idx;
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@ -2417,7 +2457,6 @@ static int __init console_setup(char *str)
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*s = 0;
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__add_preferred_console(buf, idx, options, brl_options, true);
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console_set_on_cmdline = 1;
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return 1;
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}
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__setup("console=", console_setup);
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@ -2573,6 +2612,25 @@ static int have_callable_console(void)
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return 0;
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}
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/*
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* Return true when this CPU should unlock console_sem without pushing all
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* messages to the console. This reduces the chance that the console is
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* locked when the panic CPU tries to use it.
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*/
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static bool abandon_console_lock_in_panic(void)
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{
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if (!panic_in_progress())
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return false;
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/*
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* We can use raw_smp_processor_id() here because it is impossible for
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* the task to be migrated to the panic_cpu, or away from it. If
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* panic_cpu has already been set, and we're not currently executing on
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* that CPU, then we never will be.
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*/
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return atomic_read(&panic_cpu) != raw_smp_processor_id();
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}
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/*
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* Can we actually use the console at this time on this cpu?
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*
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@ -2603,6 +2661,7 @@ void console_unlock(void)
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{
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static char ext_text[CONSOLE_EXT_LOG_MAX];
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static char text[CONSOLE_LOG_MAX];
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static int panic_console_dropped;
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unsigned long flags;
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bool do_cond_resched, retry;
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struct printk_info info;
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@ -2657,6 +2716,10 @@ void console_unlock(void)
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if (console_seq != r.info->seq) {
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console_dropped += r.info->seq - console_seq;
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console_seq = r.info->seq;
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if (panic_in_progress() && panic_console_dropped++ > 10) {
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suppress_panic_printk = 1;
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pr_warn_once("Too many dropped messages. Suppress messages on non-panic CPUs to prevent livelock.\n");
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}
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}
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if (suppress_message_printing(r.info->level)) {
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@ -2716,6 +2779,10 @@ void console_unlock(void)
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if (handover)
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return;
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/* Allow panic_cpu to take over the consoles safely */
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if (abandon_console_lock_in_panic())
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break;
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if (do_cond_resched)
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cond_resched();
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}
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@ -2733,7 +2800,7 @@ void console_unlock(void)
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* flush, no worries.
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*/
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retry = prb_read_valid(prb, next_seq, NULL);
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if (retry && console_trylock())
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if (retry && !abandon_console_lock_in_panic() && console_trylock())
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goto again;
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}
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EXPORT_SYMBOL(console_unlock);
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@ -3228,7 +3295,7 @@ static DEFINE_PER_CPU(int, printk_pending);
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static void wake_up_klogd_work_func(struct irq_work *irq_work)
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{
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int pending = __this_cpu_xchg(printk_pending, 0);
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int pending = this_cpu_xchg(printk_pending, 0);
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if (pending & PRINTK_PENDING_OUTPUT) {
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/* If trylock fails, someone else is doing the printing */
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@ -3262,7 +3329,7 @@ void defer_console_output(void)
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return;
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preempt_disable();
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__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
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this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
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irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
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preempt_enable();
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}
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|
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@ -474,8 +474,10 @@ static enum desc_state desc_read(struct prb_desc_ring *desc_ring,
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* state has been re-checked. A memcpy() for all of @desc
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* cannot be used because of the atomic_t @state_var field.
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*/
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if (desc_out) {
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memcpy(&desc_out->text_blk_lpos, &desc->text_blk_lpos,
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sizeof(desc_out->text_blk_lpos)); /* LMM(desc_read:C) */
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}
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if (seq_out)
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*seq_out = info->seq; /* also part of desc_read:C */
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if (caller_id_out)
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@ -528,6 +530,7 @@ static enum desc_state desc_read(struct prb_desc_ring *desc_ring,
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state_val = atomic_long_read(state_var); /* LMM(desc_read:E) */
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d_state = get_desc_state(id, state_val);
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out:
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if (desc_out)
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atomic_long_set(&desc_out->state_var, state_val);
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return d_state;
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}
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@ -1449,6 +1452,9 @@ static void desc_make_final(struct prb_desc_ring *desc_ring, unsigned long id)
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atomic_long_cmpxchg_relaxed(&d->state_var, prev_state_val,
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DESC_SV(id, desc_finalized)); /* LMM(desc_make_final:A) */
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/* Best effort to remember the last finalized @id. */
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atomic_long_set(&desc_ring->last_finalized_id, id);
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}
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/**
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@ -1657,7 +1663,12 @@ void prb_commit(struct prb_reserved_entry *e)
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*/
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void prb_final_commit(struct prb_reserved_entry *e)
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{
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struct prb_desc_ring *desc_ring = &e->rb->desc_ring;
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_prb_commit(e, desc_finalized);
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/* Best effort to remember the last finalized @id. */
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atomic_long_set(&desc_ring->last_finalized_id, e->id);
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}
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/*
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|
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@ -2005,9 +2016,39 @@ u64 prb_first_valid_seq(struct printk_ringbuffer *rb)
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*/
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u64 prb_next_seq(struct printk_ringbuffer *rb)
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{
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u64 seq = 0;
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struct prb_desc_ring *desc_ring = &rb->desc_ring;
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enum desc_state d_state;
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unsigned long id;
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u64 seq;
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/* Search forward from the oldest descriptor. */
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/* Check if the cached @id still points to a valid @seq. */
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id = atomic_long_read(&desc_ring->last_finalized_id);
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d_state = desc_read(desc_ring, id, NULL, &seq, NULL);
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if (d_state == desc_finalized || d_state == desc_reusable) {
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/*
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* Begin searching after the last finalized record.
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*
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* On 0, the search must begin at 0 because of hack#2
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* of the bootstrapping phase it is not known if a
|
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* record at index 0 exists.
|
||||
*/
|
||||
if (seq != 0)
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seq++;
|
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} else {
|
||||
/*
|
||||
* The information about the last finalized sequence number
|
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* has gone. It should happen only when there is a flood of
|
||||
* new messages and the ringbuffer is rapidly recycled.
|
||||
* Give up and start from the beginning.
|
||||
*/
|
||||
seq = 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* The information about the last finalized @seq might be inaccurate.
|
||||
* Search forward to find the current one.
|
||||
*/
|
||||
while (_prb_read_valid(rb, &seq, NULL, NULL))
|
||||
seq++;
|
||||
|
||||
|
|
@ -2044,6 +2085,7 @@ void prb_init(struct printk_ringbuffer *rb,
|
|||
rb->desc_ring.infos = infos;
|
||||
atomic_long_set(&rb->desc_ring.head_id, DESC0_ID(descbits));
|
||||
atomic_long_set(&rb->desc_ring.tail_id, DESC0_ID(descbits));
|
||||
atomic_long_set(&rb->desc_ring.last_finalized_id, DESC0_ID(descbits));
|
||||
|
||||
rb->text_data_ring.size_bits = textbits;
|
||||
rb->text_data_ring.data = text_buf;
|
||||
|
|
|
|||
|
|
@ -75,6 +75,7 @@ struct prb_desc_ring {
|
|||
struct printk_info *infos;
|
||||
atomic_long_t head_id;
|
||||
atomic_long_t tail_id;
|
||||
atomic_long_t last_finalized_id;
|
||||
};
|
||||
|
||||
/*
|
||||
|
|
@ -258,6 +259,7 @@ static struct printk_ringbuffer name = { \
|
|||
.infos = &_##name##_infos[0], \
|
||||
.head_id = ATOMIC_INIT(DESC0_ID(descbits)), \
|
||||
.tail_id = ATOMIC_INIT(DESC0_ID(descbits)), \
|
||||
.last_finalized_id = ATOMIC_INIT(DESC0_ID(descbits)), \
|
||||
}, \
|
||||
.text_data_ring = { \
|
||||
.size_bits = (avgtextbits) + (descbits), \
|
||||
|
|
|
|||
|
|
@ -49,10 +49,15 @@
|
|||
|
||||
#include <asm/page.h> /* for PAGE_SIZE */
|
||||
#include <asm/byteorder.h> /* cpu_to_le16 */
|
||||
#include <asm/unaligned.h>
|
||||
|
||||
#include <linux/string_helpers.h>
|
||||
#include "kstrtox.h"
|
||||
|
||||
/* Disable pointer hashing if requested */
|
||||
bool no_hash_pointers __ro_after_init;
|
||||
EXPORT_SYMBOL_GPL(no_hash_pointers);
|
||||
|
||||
static noinline unsigned long long simple_strntoull(const char *startp, size_t max_chars, char **endp, unsigned int base)
|
||||
{
|
||||
const char *cp;
|
||||
|
|
@ -850,6 +855,19 @@ static char *ptr_to_id(char *buf, char *end, const void *ptr,
|
|||
return pointer_string(buf, end, (const void *)hashval, spec);
|
||||
}
|
||||
|
||||
static char *default_pointer(char *buf, char *end, const void *ptr,
|
||||
struct printf_spec spec)
|
||||
{
|
||||
/*
|
||||
* default is to _not_ leak addresses, so hash before printing,
|
||||
* unless no_hash_pointers is specified on the command line.
|
||||
*/
|
||||
if (unlikely(no_hash_pointers))
|
||||
return pointer_string(buf, end, ptr, spec);
|
||||
|
||||
return ptr_to_id(buf, end, ptr, spec);
|
||||
}
|
||||
|
||||
int kptr_restrict __read_mostly;
|
||||
|
||||
static noinline_for_stack
|
||||
|
|
@ -859,7 +877,7 @@ char *restricted_pointer(char *buf, char *end, const void *ptr,
|
|||
switch (kptr_restrict) {
|
||||
case 0:
|
||||
/* Handle as %p, hash and do _not_ leak addresses. */
|
||||
return ptr_to_id(buf, end, ptr, spec);
|
||||
return default_pointer(buf, end, ptr, spec);
|
||||
case 1: {
|
||||
const struct cred *cred;
|
||||
|
||||
|
|
@ -1763,7 +1781,7 @@ char *fourcc_string(char *buf, char *end, const u32 *fourcc,
|
|||
char output[sizeof("0123 little-endian (0x01234567)")];
|
||||
char *p = output;
|
||||
unsigned int i;
|
||||
u32 val;
|
||||
u32 orig, val;
|
||||
|
||||
if (fmt[1] != 'c' || fmt[2] != 'c')
|
||||
return error_string(buf, end, "(%p4?)", spec);
|
||||
|
|
@ -1771,21 +1789,23 @@ char *fourcc_string(char *buf, char *end, const u32 *fourcc,
|
|||
if (check_pointer(&buf, end, fourcc, spec))
|
||||
return buf;
|
||||
|
||||
val = *fourcc & ~BIT(31);
|
||||
orig = get_unaligned(fourcc);
|
||||
val = orig & ~BIT(31);
|
||||
|
||||
for (i = 0; i < sizeof(*fourcc); i++) {
|
||||
for (i = 0; i < sizeof(u32); i++) {
|
||||
unsigned char c = val >> (i * 8);
|
||||
|
||||
/* Print non-control ASCII characters as-is, dot otherwise */
|
||||
*p++ = isascii(c) && isprint(c) ? c : '.';
|
||||
}
|
||||
|
||||
strcpy(p, *fourcc & BIT(31) ? " big-endian" : " little-endian");
|
||||
*p++ = ' ';
|
||||
strcpy(p, orig & BIT(31) ? "big-endian" : "little-endian");
|
||||
p += strlen(p);
|
||||
|
||||
*p++ = ' ';
|
||||
*p++ = '(';
|
||||
p = special_hex_number(p, output + sizeof(output) - 2, *fourcc, sizeof(u32));
|
||||
p = special_hex_number(p, output + sizeof(output) - 2, orig, sizeof(u32));
|
||||
*p++ = ')';
|
||||
*p = '\0';
|
||||
|
||||
|
|
@ -2225,10 +2245,6 @@ char *fwnode_string(char *buf, char *end, struct fwnode_handle *fwnode,
|
|||
return widen_string(buf, buf - buf_start, end, spec);
|
||||
}
|
||||
|
||||
/* Disable pointer hashing if requested */
|
||||
bool no_hash_pointers __ro_after_init;
|
||||
EXPORT_SYMBOL_GPL(no_hash_pointers);
|
||||
|
||||
int __init no_hash_pointers_enable(char *str)
|
||||
{
|
||||
if (no_hash_pointers)
|
||||
|
|
@ -2457,7 +2473,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
|
|||
case 'e':
|
||||
/* %pe with a non-ERR_PTR gets treated as plain %p */
|
||||
if (!IS_ERR(ptr))
|
||||
break;
|
||||
return default_pointer(buf, end, ptr, spec);
|
||||
return err_ptr(buf, end, ptr, spec);
|
||||
case 'u':
|
||||
case 'k':
|
||||
|
|
@ -2467,16 +2483,9 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
|
|||
default:
|
||||
return error_string(buf, end, "(einval)", spec);
|
||||
}
|
||||
default:
|
||||
return default_pointer(buf, end, ptr, spec);
|
||||
}
|
||||
|
||||
/*
|
||||
* default is to _not_ leak addresses, so hash before printing,
|
||||
* unless no_hash_pointers is specified on the command line.
|
||||
*/
|
||||
if (unlikely(no_hash_pointers))
|
||||
return pointer_string(buf, end, ptr, spec);
|
||||
else
|
||||
return ptr_to_id(buf, end, ptr, spec);
|
||||
}
|
||||
|
||||
/*
|
||||
|
|
|
|||
Loading…
Reference in New Issue