linux-stable.git/include/linux/printk.h, branch v6.6.141

lib/hexdump: print_hex_dump_bytes() calls print_hex_dump_debug()

2026-05-23T11:03:22+00:00

[ Upstream commit 36776b7f8a8955b4e75b5d490a75fee0c7a2a7ef ]

print_hex_dump_bytes() claims to be a simple wrapper around
print_hex_dump(), but it actally calls print_hex_dump_debug(), which
means no output is printed if (dynamic) DEBUG is disabled.

Update the documentation to match the implementation.

Fixes: 091cb0994edd20d6 ("lib/hexdump: make print_hex_dump_bytes() a nop on !DEBUG builds")
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Petr Mladek 
Link: https://patch.msgid.link/3d5c3069fd9102ecaf81d044b750cd613eb72a08.1774970392.git.geert+renesas@glider.be
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

printk: add print_hex_dump_devel()

2026-05-17T15:13:50+00:00

[ Upstream commit d134feeb5df33fbf77f482f52a366a44642dba09 ]

Add print_hex_dump_devel() as the hex dump equivalent of pr_devel(),
which emits output only when DEBUG is enabled, but keeps call sites
compiled otherwise.

Suggested-by: Herbert Xu 
Signed-off-by: Thorsten Blum 
Reviewed-by: John Ogness 
Signed-off-by: Herbert Xu 
Stable-dep-of: 177730a273b1 ("crypto: caam - guard HMAC key hex dumps in hash_digest_key")
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

printk: Let no_printk() use _printk()

2024-06-12T09:11:56+00:00

[ Upstream commit 8522f6b760ca588928eede740d5d69dd1e936b49 ]

When printk-indexing is enabled, each printk() invocation emits a
pi_entry structure, containing the format string and other information
related to its location in the kernel sources.  This is even true for
no_printk(): while the actual code to print the message is optimized out
by the compiler due to the always-false check, the pi_entry structure is
still emitted.

As the main purpose of no_printk() is to provide a helper to maintain
printf()-style format checking when debugging is disabled, this leads to
the inclusion in the index of lots of printk formats that cannot be
emitted by the current kernel.

Fix this by switching no_printk() from printk() to _printk().

This reduces the size of an arm64 defconfig kernel with
CONFIG_PRINTK_INDEX=y by 576 KiB.

Fixes: 337015573718b161 ("printk: Userspace format indexing support")
Signed-off-by: Geert Uytterhoeven 
Reviewed-by: Andy Shevchenko 
Reviewed-by: Xiubo Li 
Reviewed-by: Chris Down 
Reviewed-by: Petr Mladek 
Link: https://lore.kernel.org/r/56cf92edccffea970e1f40a075334dd6cf5bb2a4.1709127473.git.geert+renesas@glider.be
Signed-off-by: Petr Mladek 
Signed-off-by: Sasha Levin

printk: move size limit macros into internal.h

2023-01-11T14:35:11+00:00

The size limit macros are located further down in printk.c and
behind ifdef conditionals. This complicates their usage for
upcoming changes. Move the macros into internal.h so that they
are still invisible outside of printk, but easily accessible
for printk.

Also, the maximum size of formatted extended messages does not
need to be known by any code outside of printk, so move it to
internal.h as well. And like CONSOLE_LOG_MAX, for !CONFIG_PRINTK
set CONSOLE_EXT_LOG_MAX to 0 to reduce the static memory
footprint.

Signed-off-by: John Ogness 
Reviewed-by: Petr Mladek 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20230109100800.1085541-2-john.ogness@linutronix.de

Merge branch 'rework/kthreads' into for-linus

2022-10-04T13:55:55+00:00

printk: Make pr_flush() static

2022-09-29T13:20:22+00:00

No user outside the printk code and no reason to export this.

Signed-off-by: Thomas Gleixner 
Signed-off-by: John Ogness 
Reviewed-by: Sergey Senozhatsky 
Reviewed-by: Petr Mladek 
Reviewed-by: Greg Kroah-Hartman 
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20220924000454.3319186-2-john.ogness@linutronix.de

Merge branch 'rework/kthreads' into for-linus

2022-06-23T17:11:28+00:00

Revert "printk: add functions to prefer direct printing"

2022-06-23T16:41:40+00:00

This reverts commit 2bb2b7b57f81255c13f4395ea911d6bdc70c9fe2.

The testing of 5.19 release candidates revealed missing synchronization
between early and regular console functionality.

It would be possible to start the console kthreads later as a workaround.
But it is clear that console lock serialized console drivers between
each other. It opens a big area of possible problems that were not
considered by people involved in the development and review.

printk() is crucial for debugging kernel issues and console output is
very important part of it. The number of consoles is huge and a proper
review would take some time. As a result it need to be reverted for 5.19.

Link: https://lore.kernel.org/r/YrBdjVwBOVgLfHyb@alley
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20220623145157.21938-7-pmladek@suse.com

Revert "printk: Wait for the global console lock when the system is going down"

2022-06-23T16:41:40+00:00

This reverts commit b87f02307d3cfbda768520f0687c51ca77e14fc3.

The testing of 5.19 release candidates revealed missing synchronization
between early and regular console functionality.

It would be possible to start the console kthreads later as a workaround.
But it is clear that console lock serialized console drivers between
each other. It opens a big area of possible problems that were not
considered by people involved in the development and review.

printk() is crucial for debugging kernel issues and console output is
very important part of it. The number of consoles is huge and a proper
review would take some time. As a result it need to be reverted for 5.19.

Link: https://lore.kernel.org/r/YrBdjVwBOVgLfHyb@alley
Signed-off-by: Petr Mladek 
Link: https://lore.kernel.org/r/20220623145157.21938-2-pmladek@suse.com

Merge branch 'rework/kthreads' into for-linus

2022-06-17T14:36:48+00:00