user/sven/linux.git/kernel/debug/debug_core.c, branch v5.13

kgdb: fix to kill breakpoints on initmem after boot

2021-02-26T17:41:05Z

Currently breakpoints in kernel .init.text section are not handled correctly while allowing to remove them even after corresponding pages have been freed. Fix it via killing .init.text section breakpoints just prior to initmem pages being freed. Doug: "HW breakpoints aren't handled by this patch but it's probably not such a big deal". Link: https://lkml.kernel.org/r/20210224081652.587785-1-sumit.garg@linaro.org Signed-off-by: Sumit Garg Suggested-by: Doug Anderson Acked-by: Doug Anderson Acked-by: Daniel Thompson Tested-by: Daniel Thompson Cc: Masami Hiramatsu Cc: Steven Rostedt (VMware) Cc: Jason Wessel Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kgdb: Remove kgdb_schedule_breakpoint()

2021-02-11T10:51:56Z

To the very best of my knowledge there has never been any in-tree code that calls this function. It exists largely to support an out-of-tree driver that provides kgdb-over-ethernet using the netpoll API. kgdboe has been out-of-tree for more than 10 years and I don't recall any serious attempt to upstream it at any point in the last five. At this stage it looks better to stop carrying this code in the kernel and integrate the code into the out-of-tree driver instead. The long term trajectory for the kernel looks likely to include effort to remove or reduce the use of tasklets (something that has also been true for the last 10 years). Thus the main real reason for this patch is to make explicit that the in-tree kgdb features do not require tasklets. Signed-off-by: Daniel Thompson Link: https://lore.kernel.org/r/20210210142525.2876648-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson Acked-by: Davidlohr Bueso Acked-by: Jason Wessel

kgdb: rectify kernel-doc for kgdb_unregister_io_module()

2021-02-04T15:23:25Z

The command 'find ./kernel/debug/ | xargs ./scripts/kernel-doc -none' reported a typo in the kernel-doc of kgdb_unregister_io_module(). Rectify the kernel-doc, such that no issues remain for ./kernel/debug/. Signed-off-by: Lukas Bulwahn Link: https://lore.kernel.org/r/20210125144847.21896-1-lukas.bulwahn@gmail.com Signed-off-by: Daniel Thompson

smp: Cleanup smp_call_function*()

2020-11-24T15:47:49Z

Get rid of the __call_single_node union and cleanup the API a little to avoid external code relying on the structure layout as much. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Frederic Weisbecker

kernel: debug: Centralize dbg_[de]activate_sw_breakpoints

2020-10-01T13:23:45Z

During debug trap execution we expect dbg_deactivate_sw_breakpoints() to be paired with an dbg_activate_sw_breakpoint(). Currently although the calls are paired correctly they are needlessly smeared across three different functions. Worse this also results in code to drive polled I/O being called with breakpoints activated which, in turn, needlessly increases the set of functions that will recursively trap if breakpointed. Fix this by moving the activation of breakpoints into the debug core. Reviewed-by: Douglas Anderson Link: https://lore.kernel.org/r/20200927211531.1380577-4-daniel.thompson@linaro.org Signed-off-by: Daniel Thompson

kgdb: Add NOKPROBE labels on the trap handler functions

2020-10-01T13:23:21Z

Currently kgdb honours the kprobe blocklist but doesn't place its own trap handling code on the list. Add labels to discourage attempting to use kgdb to debug itself. Not every functions that executes from the trap handler needs to be marked up: relatively early in the trap handler execution (just after we bring the other CPUs to a halt) all breakpoints are replaced with the original opcodes. This patch marks up code in the debug_core that executes between trap entry and the breakpoints being deactivated and, also, code that executes between breakpoint activation and trap exit. To be clear these changes are not sufficient to make recursive trapping impossible since they do not include library calls made during kgdb's entry/exit logic. However going much further whilst we are sharing the kprobe blocklist risks reducing the capabilities of kprobe and this would be a bad trade off (especially so given kgdb's users are currently conditioned to avoid recursive traps). Reviewed-by: Douglas Anderson Link: https://lore.kernel.org/r/20200927211531.1380577-3-daniel.thompson@linaro.org Signed-off-by: Daniel Thompson

kgdb: Honour the kprobe blocklist when setting breakpoints

2020-09-28T11:14:08Z

Currently kgdb has absolutely no safety rails in place to discourage or prevent a user from placing a breakpoint in dangerous places such as the debugger's own trap entry/exit and other places where it is not safe to take synchronous traps. Introduce a new config symbol KGDB_HONOUR_BLOCKLIST and modify the default implementation of kgdb_validate_break_address() so that we use the kprobe blocklist to prohibit instrumentation of critical functions if the config symbol is set. The config symbol dependencies are set to ensure that the blocklist will be enabled by default if we enable KGDB and are compiling for an architecture where we HAVE_KPROBES. Suggested-by: Peter Zijlstra Reviewed-by: Douglas Anderson Reviewed-by: Masami Hiramatsu Link: https://lore.kernel.org/r/20200927211531.1380577-2-daniel.thompson@linaro.org Signed-off-by: Daniel Thompson

kernel/debug: Fix spelling mistake in debug_core.c

2020-09-11T14:57:37Z

Fix typo: "notifiter" --> "notifier" "overriden" --> "overridden" Signed-off-by: Youling Tang Link: https://lore.kernel.org/r/1596793480-22559-1-git-send-email-tangyouling@loongson.cn Signed-off-by: Daniel Thompson

kgdb: Make "kgdbcon" work properly with "kgdb_earlycon"

2020-09-08T13:34:40Z

On my system the kernel processes the "kgdb_earlycon" parameter before the "kgdbcon" parameter. When we setup "kgdb_earlycon" we'll end up in kgdb_register_callbacks() and "kgdb_use_con" won't have been set yet so we'll never get around to starting "kgdbcon". Let's remedy this by detecting that the IO module was already registered when setting "kgdb_use_con" and registering the console then. As part of this, to avoid pre-declaring things, move the handling of the "kgdbcon" further down in the file. Signed-off-by: Douglas Anderson Link: https://lore.kernel.org/r/20200630151422.1.I4aa062751ff5e281f5116655c976dff545c09a46@changeid Signed-off-by: Daniel Thompson

treewide: Replace DECLARE_TASKLET() with DECLARE_TASKLET_OLD()

2020-07-30T18:15:58Z

This converts all the existing DECLARE_TASKLET() (and ...DISABLED) macros with DECLARE_TASKLET_OLD() in preparation for refactoring the tasklet callback type. All existing DECLARE_TASKLET() users had a "0" data argument, it has been removed here as well. Reviewed-by: Greg Kroah-Hartman Acked-by: Thomas Gleixner Signed-off-by: Kees Cook