kernel/linux.git/lib/dump_stack.c, branch v6.19.11

panic/printk: replace this_cpu_in_panic() with panic_on_this_cpu()

2025-09-14T00:32:52+00:00

The helper this_cpu_in_panic() duplicated logic already provided by panic_on_this_cpu(). Remove this_cpu_in_panic() and switch all users to panic_on_this_cpu(). This simplifies the code and avoids having two helpers for the same check. Link: https://lkml.kernel.org/r/20250825022947.1596226-8-wangjinchao600@gmail.com Signed-off-by: Jinchao Wang Cc: Anna Schumaker Cc: Baoquan He Cc: "Darrick J. Wong" Cc: Dave Young Cc: Doug Anderson Cc: "Guilherme G. Piccoli" Cc: Helge Deller Cc: Ingo Molnar Cc: Jason Gunthorpe Cc: Joanthan Cameron Cc: Joel Granados Cc: John Ogness Cc: Kees Cook Cc: Li Huafei Cc: "Luck, Tony" Cc: Luo Gengkun Cc: Max Kellermann Cc: Nam Cao Cc: oushixiong Cc: Petr Mladek Cc: Qianqiang Liu Cc: Sergey Senozhatsky Cc: Sohil Mehta Cc: Steven Rostedt Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Zimemrmann Cc: Thorsten Blum Cc: Ville Syrjala Cc: Vivek Goyal Cc: Yicong Yang Cc: Yunhui Cui Cc: Yury Norov (NVIDIA) Signed-off-by: Andrew Morton

lib/dump_stack: Use preempt_model_str()

2025-03-17T10:23:39+00:00

Use preempt_model_str() to print the current preemption model. Use pr_warn() instead of printk() to pass a loglevel. This makes it part of generic WARN/ BUG traces. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20250314160810.2373416-3-bigeasy@linutronix.de

Merge tag 'v6.11-rc1' into for-6.12

2024-07-30T19:30:11+00:00

Linux 6.11-rc1

lib/dump_stack: report process UID in dump_stack_print_info()

2024-06-25T05:25:11+00:00

To make it easier to identify the crashing process, report effective UID when dumping the stack. Link: https://lkml.kernel.org/r/20240615041358.103791-1-surenb@google.com Signed-off-by: Suren Baghdasaryan Signed-off-by: Andrew Morton

kernel/panic: add verbose logging of kernel taints in backtraces

2024-06-25T05:25:05+00:00

With nearly 20 taint flags and respective characters, it's getting a bit difficult to remember what each taint flag character means. Add verbose logging of the set taints in the format: Tainted: [P]=PROPRIETARY_MODULE, [W]=WARN in dump_stack_print_info() when there are taints. Note that the "negative flag" G is not included. Link: https://lkml.kernel.org/r/7321e306166cb2ca2807ab8639e665baa2462e9c.1717146197.git.jani.nikula@intel.com Signed-off-by: Jani Nikula Reviewed-by: Greg Kroah-Hartman Signed-off-by: Andrew Morton

sched_ext: Print sched_ext info when dumping stack

2024-06-18T20:09:18+00:00

It would be useful to see what the sched_ext scheduler state is, and what scheduler is running, when we're dumping a task's stack. This patch therefore adds a new print_scx_info() function that's called in the same context as print_worker_info() and print_stop_info(). An example dump follows. BUG: kernel NULL pointer dereference, address: 0000000000000999 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] PREEMPT SMP CPU: 13 PID: 2047 Comm: insmod Tainted: G O 6.6.0-work-10323-gb58d4cae8e99-dirty #34 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS unknown 2/2/2022 Sched_ext: qmap (enabled+all), task: runnable_at=-17ms RIP: 0010:init_module+0x9/0x1000 [test_module] ... v3: - scx_ops_enable_state_str[] definition moved to an earlier patch as it's now used by core implementation. - Convert jiffy delta to msecs using jiffies_to_msecs() instead of multiplying by (HZ / MSEC_PER_SEC). The conversion is implemented in jiffies_delta_msecs(). v2: - We are now using scx_ops_enable_state_str[] outside CONFIG_SCHED_DEBUG. Move it outside of CONFIG_SCHED_DEBUG and to the top. This was reported by Changwoo and Andrea. Signed-off-by: David Vernet Reported-by: Changwoo Min Reported-by: Andrea Righi Signed-off-by: Tejun Heo

dump_stack: Do not get cpu_sync for panic CPU

2024-02-07T16:23:19+00:00

dump_stack() is called in panic(). If for some reason another CPU is holding the printk_cpu_sync and is unable to release it, the panic CPU will be unable to continue and print the stacktrace. Since non-panic CPUs are not allowed to store new printk messages anyway, there is no need to synchronize the stacktrace output in a panic situation. For the panic CPU, do not get the printk_cpu_sync because it is not needed and avoids a potential deadlock scenario in panic(). Link: https://lore.kernel.org/lkml/ZcIGKU8sxti38Kok@alley Signed-off-by: John Ogness Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20240207134103.1357162-15-john.ogness@linutronix.de Signed-off-by: Petr Mladek

printk: rename cpulock functions

2022-04-22T19:30:57+00:00

Since the printk cpulock is CPU-reentrant and since it is used in all contexts, its usage must be carefully considered and most likely will require programming locklessly. To avoid mistaking the printk cpulock as a typical lock, rename it to cpu_sync. The main functions then become: printk_cpu_sync_get_irqsave(flags); printk_cpu_sync_put_irqrestore(flags); Add extra notes of caution in the function description to help developers understand the requirements for correct usage. Signed-off-by: John Ogness Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek Link: https://lore.kernel.org/r/20220421212250.565456-2-john.ogness@linutronix.de

lib/dump_stack: correct kernel-doc notation

2021-09-08T18:50:26+00:00

Fix kernel-doc warnings in dump_stack.c: lib/dump_stack.c:97: warning: Function parameter or member 'log_lvl' not described in 'dump_stack_lvl' lib/dump_stack.c:97: warning: expecting prototype for dump_stack(). Prototype was for dump_stack_lvl() instead Link: https://lkml.kernel.org/r/20210809051643.17567-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap Cc: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

dump_stack: add vmlinux build ID to stack traces

2021-07-08T18:48:22+00:00

Add the running kernel's build ID[1] to the stacktrace information header. This makes it simpler for developers to locate the vmlinux with full debuginfo for a particular kernel stacktrace. Combined with scripts/decode_stracktrace.sh, a developer can download the correct vmlinux from a debuginfod[2] server and find the exact file and line number for the functions plus offsets in a stacktrace. This is especially useful for pstore crash debugging where the kernel crashes are recorded in the pstore logs and the recovery kernel is different or the debuginfo doesn't exist on the device due to space concerns (the data can be large and a security concern). The stacktrace can be analyzed after the crash by using the build ID to find the matching vmlinux and understand where in the function something went wrong. Example stacktrace from lkdtm: WARNING: CPU: 4 PID: 3255 at drivers/misc/lkdtm/bugs.c:83 lkdtm_WARNING+0x28/0x30 [lkdtm] Modules linked in: lkdtm rfcomm algif_hash algif_skcipher af_alg xt_cgroup uinput xt_MASQUERADE CPU: 4 PID: 3255 Comm: bash Not tainted 5.11 #3 aa23f7a1231c229de205662d5a9e0d4c580f19a1 Hardware name: Google Lazor (rev3+) with KB Backlight (DT) pstate: 00400009 (nzcv daif +PAN -UAO -TCO BTYPE=--) pc : lkdtm_WARNING+0x28/0x30 [lkdtm] The hex string aa23f7a1231c229de205662d5a9e0d4c580f19a1 is the build ID, following the kernel version number. Put it all behind a config option, STACKTRACE_BUILD_ID, so that kernel developers can remove this information if they decide it is too much. Link: https://lkml.kernel.org/r/20210511003845.2429846-5-swboyd@chromium.org Link: https://fedoraproject.org/wiki/Releases/FeatureBuildId [1] Link: https://sourceware.org/elfutils/Debuginfod.html [2] Signed-off-by: Stephen Boyd Cc: Jiri Olsa Cc: Alexei Starovoitov Cc: Jessica Yu Cc: Evan Green Cc: Hsin-Yi Wang Cc: Petr Mladek Cc: Steven Rostedt Cc: Andy Shevchenko Cc: Matthew Wilcox Cc: Baoquan He Cc: Borislav Petkov Cc: Catalin Marinas Cc: Dave Young Cc: Ingo Molnar Cc: Konstantin Khlebnikov Cc: Rasmus Villemoes Cc: Sasha Levin Cc: Sergey Senozhatsky Cc: Thomas Gleixner Cc: Vivek Goyal Cc: Will Deacon Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds