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Wed, 10 Sep 2025 16:21:37 +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 TsBbKZGlwWjCRwAAD6G6ig (envelope-from ); Wed, 10 Sep 2025 16:21:37 +0000 From: Pedro Falcato To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org Cc: "H. Peter Anvin" , "Peter Zijlstra (Intel)" , Maksim Davydov , linux-kernel@vger.kernel.org, Pedro Falcato Subject: [PATCH RESEND] x86/split_lock: Warn for bus locks once for each task Date: Wed, 10 Sep 2025 17:21:26 +0100 Message-ID: <20250910162126.157894-1-pfalcato@suse.de> X-Mailer: git-send-email 2.51.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Spamd-Result: default: False [-3.01 / 50.00]; BAYES_HAM(-3.00)[100.00%]; NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[]; R_MISSING_CHARSET(0.50)[]; R_DKIM_ALLOW(-0.20)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MX_GOOD(-0.01)[]; ARC_NA(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; RCVD_COUNT_TWO(0.00)[2]; FUZZY_RATELIMITED(0.00)[rspamd.com]; MIME_TRACE(0.00)[0:+]; RBL_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:104:10:150:64:97:from]; TO_DN_SOME(0.00)[]; FROM_HAS_DN(0.00)[]; RECEIVED_SPAMHAUS_BLOCKED_OPENRESOLVER(0.00)[2a07:de40:b281:106:10:150:64:167:received]; RCPT_COUNT_SEVEN(0.00)[10]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,imap1.dmz-prg2.suse.org:rdns,suse.de:mid,suse.de:dkim,suse.de:email]; RCVD_TLS_ALL(0.00)[]; FROM_EQ_ENVFROM(0.00)[]; SPAMHAUS_XBL(0.00)[2a07:de40:b281:104:10:150:64:97:from]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; DKIM_TRACE(0.00)[suse.de:+] X-Spam-Flag: NO X-Spam-Level: X-Rspamd-Queue-Id: 69B8F66E1A X-Rspamd-Server: rspamd2.dmz-prg2.suse.org X-Rspamd-Action: no action X-Spam-Score: -3.01 Content-Type: text/plain; charset="utf-8" Sometimes, it's possible to see long-running services that keep pounding the bus_lock logic in a long-standing way that does not trigger ratelimiting, but still floods the dmesg nonetheless, over time. Fix it by using current->reported_split_lock, which was previously used for the split_lock handling. In this way, bus_lock #DB's are only warned once in the dmesg, for each task that hits a bus lock. Signed-off-by: Pedro Falcato --- This is already reflected in the documentation for bus lock, as "Warn once per task and and continues to run.". Resend since the first mail had accidentally no mailing list in CC. arch/x86/kernel/cpu/bus_lock.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/bus_lock.c b/arch/x86/kernel/cpu/bus_lock.c index 981f8b1f0792..71342e6244e3 100644 --- a/arch/x86/kernel/cpu/bus_lock.c +++ b/arch/x86/kernel/cpu/bus_lock.c @@ -335,8 +335,11 @@ void handle_bus_lock(struct pt_regs *regs) /* Warn on the bus lock. */ fallthrough; case sld_warn: - pr_warn_ratelimited("#DB: %s/%d took a bus_lock trap at address: 0x%lx\n= ", + if (!current->reported_split_lock) { + pr_warn_ratelimited("#DB: %s/%d took a bus_lock trap at address: 0x%lx\= n", current->comm, current->pid, regs->ip); + current->reported_split_lock =3D 1; + } break; case sld_fatal: force_sig_fault(SIGBUS, BUS_ADRALN, NULL); --=20 2.51.0