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Wed, 16 Oct 2024 17:03:25 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 75SzLN3xD2dsTQAAD6G6ig (envelope-from ); Wed, 16 Oct 2024 17:03:25 +0000 From: Marcos Paulo de Souza Date: Wed, 16 Oct 2024 14:03:01 -0300 Subject: [PATCH 1/2] printk: Introduce LOUD_CON flag Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241016-printk-loud-con-v1-1-065e4dad6632@suse.com> References: <20241016-printk-loud-con-v1-0-065e4dad6632@suse.com> In-Reply-To: <20241016-printk-loud-con-v1-0-065e4dad6632@suse.com> To: Petr Mladek , Steven Rostedt , John Ogness , Sergey Senozhatsky , Greg Kroah-Hartman , Jiri Slaby Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Marcos Paulo de Souza X-Mailer: b4 0.14-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1729098195; l=5104; i=mpdesouza@suse.com; s=20231031; h=from:subject:message-id; bh=FdXPrW1TypyQ/5h3ZLuD+3Lt7hB/A/9rTUFSTmspdNs=; b=yXF+4fylnN+KNRedDqClvv7HS4D7E97Wnngkq7JJZr4HkjxAU0MEjj4WIwp2h7Zm3/dnea3FO uxCFz02oFrFA8zMyEuROhlIJKAXrhEAMsvL61GwcpZliFCWC7kSGnwe X-Developer-Key: i=mpdesouza@suse.com; a=ed25519; pk=/Ni/TsKkr69EOmdZXkp1Q/BlzDonbOBRsfPa18ySIwU= X-Spam-Level: X-Spamd-Result: default: False [-8.30 / 50.00]; REPLY(-4.00)[]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MID_RHS_MATCH_FROM(0.00)[]; RCPT_COUNT_SEVEN(0.00)[9]; MIME_TRACE(0.00)[0:+]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; RCVD_TLS_ALL(0.00)[]; DKIM_SIGNED(0.00)[suse.com:s=susede1]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[suse.com:email,suse.com:mid] X-Spam-Score: -8.30 X-Spam-Flag: NO Introduce LOUD_CON flag to printk. The new flag will make it possible to create a context where printk messages will never be suppressed. This new context information will be stored in the already existing printk_context per-CPU variable. This variable was changed from 'int' to 'unsigned int' to avoid issues with automatic casting. This mechanism will be used in the next patch to create a loud_console context on sysrq handling, removing an existing workaround on the loglevel global variable. The workaround existed to make sure that sysrq header messages were sent to all consoles. Signed-off-by: Marcos Paulo de Souza --- include/linux/printk.h | 3 +++ kernel/printk/internal.h | 3 +++ kernel/printk/printk.c | 8 +++++++- kernel/printk/printk_safe.c | 27 +++++++++++++++++++++++++-- 4 files changed, 38 insertions(+), 3 deletions(-) diff --git a/include/linux/printk.h b/include/linux/printk.h index eca9bb2ee637..0ac9879d94ac 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -166,6 +166,9 @@ __printf(1, 2) __cold int _printk_deferred(const char *= fmt, ...); extern void __printk_deferred_enter(void); extern void __printk_deferred_exit(void); =20 +extern void printk_loud_console_enter(void); +extern void printk_loud_console_exit(void); + /* * The printk_deferred_enter/exit macros are available only as a hack for * some code paths that need to defer all printk console printing. Interru= pts diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 3fcb48502adb..2649e8a66cef 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -53,6 +53,8 @@ int devkmsg_sysctl_set_loglvl(const struct ctl_table *tab= le, int write, =20 /* Flags for a single printk record. */ enum printk_info_flags { + /* always show on console, ignore console_loglevel */ + LOG_LOUD_CON =3D 1, LOG_NEWLINE =3D 2, /* text ended with a newline */ LOG_CONT =3D 8, /* text is a fragment of a continuation line */ }; @@ -90,6 +92,7 @@ bool printk_percpu_data_ready(void); =20 void defer_console_output(void); bool is_printk_legacy_deferred(void); +bool is_printk_console_loud(void); =20 u16 printk_parse_prefix(const char *text, int *level, enum printk_info_flags *flags); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index beb808f4c367..b893825fe21d 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1321,6 +1321,7 @@ static void boot_delay_msec(int level) unsigned long timeout; =20 if ((boot_delay =3D=3D 0 || system_state >=3D SYSTEM_RUNNING) + || is_printk_console_loud() || suppress_message_printing(level)) { return; } @@ -2273,6 +2274,9 @@ int vprintk_store(int facility, int level, if (dev_info) flags |=3D LOG_NEWLINE; =20 + if (is_printk_console_loud()) + flags |=3D LOG_LOUD_CON; + if (flags & LOG_CONT) { prb_rec_init_wr(&r, reserve_size); if (prb_reserve_in_last(&e, prb, &r, caller_id, PRINTKRB_RECORD_MAX)) { @@ -2947,6 +2951,7 @@ bool printk_get_next_message(struct printk_message *p= msg, u64 seq, struct printk_info info; struct printk_record r; size_t len =3D 0; + bool loud_con; =20 /* * Formatting extended messages requires a separate buffer, so use the @@ -2965,9 +2970,10 @@ bool printk_get_next_message(struct printk_message *= pmsg, u64 seq, =20 pmsg->seq =3D r.info->seq; pmsg->dropped =3D r.info->seq - seq; + loud_con =3D r.info->flags & LOG_LOUD_CON; =20 /* Skip record that has level above the console loglevel. */ - if (may_suppress && suppress_message_printing(r.info->level)) + if (!loud_con && may_suppress && suppress_message_printing(r.info->level)) goto out; =20 if (is_extended) { diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 2b35a9d3919d..4618988baeea 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -12,7 +12,30 @@ =20 #include "internal.h" =20 -static DEFINE_PER_CPU(int, printk_context); +static DEFINE_PER_CPU(unsigned int, printk_context); + +#define PRINTK_SAFE_CONTEXT_MASK 0x0000ffffU +#define PRINTK_LOUD_CONSOLE_CONTEXT_MASK 0xffff0000U +#define PRINTK_LOUD_CONSOLE_CONTEXT_OFFSET 0x00010000U + +void noinstr printk_loud_console_enter(void) +{ + cant_migrate(); + this_cpu_add(printk_context, PRINTK_LOUD_CONSOLE_CONTEXT_OFFSET); +} + +void noinstr printk_loud_console_exit(void) +{ + cant_migrate(); + this_cpu_sub(printk_context, PRINTK_LOUD_CONSOLE_CONTEXT_OFFSET); +} + +/* Safe in any context. CPU migration is always disabled when set. */ +bool is_printk_console_loud(void) +{ + return !!(this_cpu_read(printk_context) & + PRINTK_LOUD_CONSOLE_CONTEXT_MASK); +} =20 /* Can be preempted by NMI. */ void __printk_safe_enter(void) @@ -45,7 +68,7 @@ bool is_printk_legacy_deferred(void) * context. CPU migration is always disabled when set. */ return (force_legacy_kthread() || - this_cpu_read(printk_context) || + !!(this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK) || in_nmi()); } =20 --=20 2.46.1 From nobody Tue Nov 26 17:25:24 2024 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.223.130]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 73E04212634; Wed, 16 Oct 2024 17:03:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=195.135.223.130 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729098213; cv=none; b=GYnOAy/n/w77Y9XxVt6KCuD0NYFKPFBdc4R3ZUiFevyjUUpTpVkAQRyVsIe04w5gQ3l/PEtx2Ex0UAzPDavRqcBVmGusHUolsWXe0d1eQa0qOW+zzAtCrnGE3iIkSjfuJatiAdBsNQbf2+6qUMi6RJ14ulFMzGJVdhhVjmixRDE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729098213; c=relaxed/simple; bh=F/aU2sHXwjZHWO3m/bFKodRBVQZGao3dZspIyBubxII=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=AjPl9BbUisRY3xrP0LI0RCtV6m7nIItJwRAhTcllSJqJTwnCFnejj49Ad7dpSH8L/bqp6tZfKzEvWEtBHb+tIdMQ66XO/vZ9NtamrazwfH3om2iWfCYkZREuJYGJqehZxz846eSBXWy5P4XSVmwqNiBKQl/RD81bRQuJ6q1Px/c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; arc=none smtp.client-ip=195.135.223.130 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Received: from imap1.dmz-prg2.suse.org (imap1.dmz-prg2.suse.org [IPv6:2a07:de40:b281:104:10:150:64:97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id B979421EE1; Wed, 16 Oct 2024 17:03:29 +0000 (UTC) Authentication-Results: smtp-out1.suse.de; none Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 3FC9513433; Wed, 16 Oct 2024 17:03:29 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id 9e6QAeHxD2dyTQAAD6G6ig (envelope-from ); Wed, 16 Oct 2024 17:03:29 +0000 From: Marcos Paulo de Souza Date: Wed, 16 Oct 2024 14:03:02 -0300 Subject: [PATCH 2/2] tty: sysrq: Use printk_loud_console context on __handle_sysrq Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241016-printk-loud-con-v1-2-065e4dad6632@suse.com> References: <20241016-printk-loud-con-v1-0-065e4dad6632@suse.com> In-Reply-To: <20241016-printk-loud-con-v1-0-065e4dad6632@suse.com> To: Petr Mladek , Steven Rostedt , John Ogness , Sergey Senozhatsky , Greg Kroah-Hartman , Jiri Slaby Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Marcos Paulo de Souza X-Mailer: b4 0.14-dev X-Developer-Signature: v=1; a=ed25519-sha256; t=1729098195; l=2232; i=mpdesouza@suse.com; s=20231031; h=from:subject:message-id; bh=F/aU2sHXwjZHWO3m/bFKodRBVQZGao3dZspIyBubxII=; b=IuIKzjlkdpQ6PhHDrZvZO+AXN3E0QXYqHX1yuTLlWDk5Q7q65QT4o6CK+uA8/zhhJgfRIAGP7 Va1Wk5NWACXDk/8lnj3DtYp6a2xX55sZeK3uogVc0ptegCZR25EJAWf X-Developer-Key: i=mpdesouza@suse.com; a=ed25519; pk=/Ni/TsKkr69EOmdZXkp1Q/BlzDonbOBRsfPa18ySIwU= X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spam-Level: X-Spamd-Result: default: False [-4.00 / 50.00]; REPLY(-4.00)[]; ASN(0.00)[asn:25478, ipnet:::/0, country:RU] X-Spam-Score: -4.00 X-Spam-Flag: NO X-Rspamd-Queue-Id: B979421EE1 X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Rspamd-Action: no action X-Rspamd-Server: rspamd2.dmz-prg2.suse.org By using the printk_loud_console the loglevel workaround can be removed. The workaround existed to always send the sysrq header message to all consoles not matter what was the current loglevel. Signed-off-by: Marcos Paulo de Souza --- drivers/tty/sysrq.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 930b04e3d148..1ff11cf6275a 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -583,7 +583,6 @@ static void __sysrq_put_key_op(u8 key, const struct sys= rq_key_op *op_p) void __handle_sysrq(u8 key, bool check_mask) { const struct sysrq_key_op *op_p; - int orig_log_level; int orig_suppress_printk; int i; =20 @@ -593,13 +592,12 @@ void __handle_sysrq(u8 key, bool check_mask) rcu_sysrq_start(); rcu_read_lock(); /* - * Raise the apparent loglevel to maximum so that the sysrq header - * is shown to provide the user with positive feedback. We do not - * simply emit this at KERN_EMERG as that would change message - * routing in the consumers of /proc/kmsg. + * Enter in the console_loud context so that sysrq header is shown to + * provide the user with positive feedback. We do not simply emit this + * at KERN_EMERG as that would change message routing in the consumers + * of /proc/kmsg. */ - orig_log_level =3D console_loglevel; - console_loglevel =3D CONSOLE_LOGLEVEL_DEFAULT; + printk_loud_console_enter(); =20 op_p =3D __sysrq_get_key_op(key); if (op_p) { @@ -609,11 +607,11 @@ void __handle_sysrq(u8 key, bool check_mask) */ if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { pr_info("%s\n", op_p->action_msg); - console_loglevel =3D orig_log_level; + printk_loud_console_exit(); op_p->handler(key); } else { pr_info("This sysrq operation is disabled.\n"); - console_loglevel =3D orig_log_level; + printk_loud_console_exit(); } } else { pr_info("HELP : "); @@ -631,7 +629,7 @@ void __handle_sysrq(u8 key, bool check_mask) } } pr_cont("\n"); - console_loglevel =3D orig_log_level; + printk_loud_console_exit(); } rcu_read_unlock(); rcu_sysrq_end(); --=20 2.46.1