linux-toradex.git/lib/bug.c, branch v6.19-rc6

bug: Hush suggest-attribute=format for __warn_printf()

2025-12-12T09:26:26+00:00

Recent additions to this function cause GCC 14.3.0 to get excited
(W=1) and suggest a missing attribute:

	lib/bug.c: In function '__warn_printf':
	lib/bug.c:187:25: error: function '__warn_printf' be a candidate for 'gnu_printf' format attribute [-Werror=suggest-attribute=format]
	  187 |                         vprintk(fmt, *args);
	      |                         ^~~~~~~

Disable the diagnostic locally, following the pattern used for stuff
like va_format().

Fixes: 5c47b7f3d1a9 ("bug: Add BUG_FORMAT_ARGS infrastructure")
Signed-off-by: Brendan Jackman 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Link: https://patch.msgid.link/20251207-warn-printf-gcc-v1-1-b597d612b94b@google.com

bug: Let report_bug_entry() provide the correct bugaddr

2025-12-12T09:26:13+00:00

report_bug_entry() always provides zero for bugaddr but could easily
extract the correct address from the provided bug_entry. Just do that to
have proper warning messages.

E.g. adding an artificial:

  void foo(void) { WARN_ONCE(1, "bar"); }

function generates this warning message:

  WARNING: arch/s390/kernel/setup.c:1017 at 0x0, CPU#0: swapper/0/0
                                            ^^^

With the correct bug address this changes to:

  WARNING: arch/s390/kernel/setup.c:1017 at foo+0x1c/0x40, CPU#0: swapper/0/0
                                            ^^^^^^^^^^^^^

Fixes: 7d2c27a0ec5e ("bug: Add report_bug_entry()")
Signed-off-by: Heiko Carstens 
Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Link: https://patch.msgid.link/20251208200658.3431511-1-hca@linux.ibm.com

x86/bug: Fix BUG_FORMAT vs KASLR

2025-11-27T08:32:47+00:00

Encoding a relative NULL pointer doesn't work for KASLR, when the
whole kernel image gets shifted, the __bug_table and the target string
get shifted by the same amount and the relative offset is preserved.

However when the target is an absolute 0 value and the __bug_table
gets moved about, the end result in a pointer equivalent to
kaslr_offset(), not NULL.

Notably, this will generate SHN_UNDEF relocations, and Ard would
really like to not have those at all.

Use the empty string to denote no-string.

Suggested-by: Linus Torvalds 
Cc: Ard Biesheuvel 
Signed-off-by: Peter Zijlstra (Intel)

bug: Add report_bug_entry()

2025-11-21T10:21:31+00:00

Add a report_bug() variant where the bug_entry is already known. This
is useful when the exception instruction is not instantiated per-site.
But instead has a single instance. In such a case the bug_entry
address might be passed along in a known register or something.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20251110115757.575795595@infradead.org

bug: Add BUG_FORMAT_ARGS infrastructure

2025-11-21T10:21:31+00:00

Add BUG_FORMAT_ARGS; when an architecture is able to provide a va_list
given pt_regs, use this to print format arguments.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20251110115757.457339417@infradead.org

bug: Add BUG_FORMAT infrastructure

2025-11-21T10:21:30+00:00

Add BUG_FORMAT; an architecture opt-in feature that allows adding the
WARN_printf() format string to the bug_entry table.

Signed-off-by: Peter Zijlstra (Intel) 
Link: https://patch.msgid.link/20251110115757.223371452@infradead.org

bug: Use RCU instead RCU-sched to protect module_bug_list.

2025-03-10T10:54:46+00:00

The list module_bug_list relies on module_mutex for writer
synchronisation. The list is already RCU style.
The list removal is synchronized with modules' synchronize_rcu() in
free_module().

Use RCU read lock protection instead of RCU-sched.

Cc: Andrew Morton 
Signed-off-by: Sebastian Andrzej Siewior 
Acked-by: Peter Zijlstra (Intel) 
Link: https://lore.kernel.org/r/20250108090457.512198-29-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu

cpuidle: lib/bug: Disable rcu_is_watching() during WARN/BUG

2023-01-31T14:01:45+00:00

In order to avoid WARN/BUG from generating nested or even recursive
warnings, force rcu_is_watching() true during
WARN/lockdep_rcu_suspicious().

Notably things like unwinding the stack can trigger rcu_dereference()
warnings, which then triggers more unwinding which then triggers more
warnings etc..

Signed-off-by: Peter Zijlstra (Intel) 
Signed-off-by: Ingo Molnar 
Link: https://lore.kernel.org/r/20230126151323.408156109@infradead.org

bug: Use normal relative pointers in 'struct bug_entry'

2022-05-19T21:46:10+00:00

With CONFIG_GENERIC_BUG_RELATIVE_POINTERS, the addr/file relative
pointers are calculated weirdly: based on the beginning of the bug_entry
struct address, rather than their respective pointer addresses.

Make the relative pointers less surprising to both humans and tools by
calculating them the normal way.

Signed-off-by: Josh Poimboeuf 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Mark Rutland 
Acked-by: Peter Zijlstra (Intel) 
Acked-by: Sven Schnelle  # s390
Acked-by: Michael Ellerman  (powerpc)
Acked-by: Catalin Marinas 
Tested-by: Mark Rutland  [arm64]
Link: https://lkml.kernel.org/r/f0e05be797a16f4fc2401eeb88c8450dcbe61df6.1652362951.git.jpoimboe@kernel.org

bug: Assign values once in bug_get_file_line()

2021-04-01T08:54:37+00:00

Set bug_get_file_line()'s output parameter values directly rather than
first nullifying them and then conditionally setting new values.

Signed-off-by: Andrew Scull 
Cc: Peter Zijlstra 
Cc: "Steven Rostedt (VMware)" 
Acked-by: Will Deacon 
Signed-off-by: Marc Zyngier 
Link: https://lore.kernel.org/r/20210318143311.839894-4-ascull@google.com