user/sven/linux.git/kernel/debug/kdb, branch v5.9.8

kdb: Fix pager search for multi-line strings

2020-10-29T09:11:47Z

[ Upstream commit d081a6e353168f15e63eb9e9334757f20343319f ] Currently using forward search doesn't handle multi-line strings correctly. The search routine replaces line breaks with \0 during the search and, for regular searches ("help | grep Common\n"), there is code after the line has been discarded or printed to replace the break character. However during a pager search ("help\n" followed by "/Common\n") when the string is matched we will immediately return to normal output and the code that should restore the \n becomes unreachable. Fix this by restoring the replaced character when we disable the search mode and update the comment accordingly. Fixes: fb6daa7520f9d ("kdb: Provide forward search at more prompt") Link: https://lore.kernel.org/r/20200909141708.338273-1-daniel.thompson@linaro.org Reviewed-by: Douglas Anderson Signed-off-by: Daniel Thompson Signed-off-by: Sasha Levin

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59Z

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

treewide: Remove uninitialized_var() usage

2020-07-16T19:35:15Z

Using uninitialized_var() is dangerous as it papers over real bugs[1] (or can in the future), and suppresses unrelated compiler warnings (e.g. "unused variable"). If the compiler thinks it is uninitialized, either simply initialize the variable or make compiler changes. In preparation for removing[2] the[3] macro[4], remove all remaining needless uses with the following script: git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \ xargs perl -pi -e \ 's/\buninitialized_var$([^$]+)\)/\1/g; s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;' drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid pathological white-space. No outstanding warnings were found building allmodconfig with GCC 9.3.0 for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64, alpha, and m68k. [1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ [2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ [3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ [4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ Reviewed-by: Leon Romanovsky # drivers/infiniband and mlx4/mlx5 Acked-by: Jason Gunthorpe # IB Acked-by: Kalle Valo # wireless drivers Reviewed-by: Chao Yu # erofs Signed-off-by: Kees Cook

kdb: Switch to use safer dbg_io_ops over console APIs

2020-06-26T14:40:16Z

In kgdb context, calling console handlers aren't safe due to locks used in those handlers which could in turn lead to a deadlock. Although, using oops_in_progress increases the chance to bypass locks in most console handlers but it might not be sufficient enough in case a console uses more locks (VT/TTY is good example). Currently when a driver provides both polling I/O and a console then kdb will output using the console. We can increase robustness by using the currently active polling I/O driver (which should be lockless) instead of the corresponding console. For several common cases (e.g. an embedded system with a single serial port that is used both for console output and debugger I/O) this will result in no console handler being used. In order to achieve this we need to reverse the order of preference to use dbg_io_ops (uses polling I/O mode) over console APIs. So we just store "struct console" that represents debugger I/O in dbg_io_ops and while emitting kdb messages, skip console that matches dbg_io_ops console in order to avoid duplicate messages. After this change, "is_console" param becomes redundant and hence removed. Suggested-by: Daniel Thompson Signed-off-by: Sumit Garg Link: https://lore.kernel.org/r/1591264879-25920-5-git-send-email-sumit.garg@linaro.org Reviewed-by: Douglas Anderson Reviewed-by: Petr Mladek Acked-by: Greg Kroah-Hartman Signed-off-by: Daniel Thompson

kdb: Make kdb_printf() console handling more robust

2020-06-25T11:04:30Z

While rounding up CPUs via NMIs, its possible that a rounded up CPU maybe holding a console port lock leading to kgdb master CPU stuck in a deadlock during invocation of console write operations. A similar deadlock could also be possible while using synchronous breakpoints. So in order to avoid such a deadlock, set oops_in_progress to encourage the console drivers to disregard their internal spin locks: in the current calling context the risk of deadlock is a bigger problem than risks due to re-entering the console driver. We operate directly on oops_in_progress rather than using bust_spinlocks() because the calls bust_spinlocks() makes on exit are not appropriate for this calling context. Suggested-by: Sergey Senozhatsky Signed-off-by: Sumit Garg Reviewed-by: Douglas Anderson Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/1591264879-25920-4-git-send-email-sumit.garg@linaro.org Signed-off-by: Daniel Thompson

kdb: Check status of console prior to invoking handlers

2020-06-25T11:04:29Z

Check if a console is enabled prior to invoking corresponding write handler. Suggested-by: Sergey Senozhatsky Signed-off-by: Sumit Garg Reviewed-by: Daniel Thompson Reviewed-by: Douglas Anderson Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/1591264879-25920-3-git-send-email-sumit.garg@linaro.org Signed-off-by: Daniel Thompson

kdb: Re-factor kdb_printf() message write code

2020-06-25T11:04:29Z

Re-factor kdb_printf() message write code in order to avoid duplication of code and thereby increase readability. Signed-off-by: Sumit Garg Reviewed-by: Douglas Anderson Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/1591264879-25920-2-git-send-email-sumit.garg@linaro.org Signed-off-by: Daniel Thompson

maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

2020-06-17T17:57:41Z

Better describe what these functions do. Suggested-by: Linus Torvalds Signed-off-by: Christoph Hellwig Signed-off-by: Linus Torvalds

kernel: rename show_stack_loglvl() => show_stack()

2020-06-09T16:39:13Z

Now the last users of show_stack() got converted to use an explicit log level, show_stack_loglvl() can drop it's redundant suffix and become once again well known show_stack(). Signed-off-by: Dmitry Safonov Signed-off-by: Andrew Morton Link: http://lkml.kernel.org/r/20200418201944.482088-51-dima@arista.com Signed-off-by: Linus Torvalds

kdb: don't play with console_loglevel

2020-06-09T16:39:12Z

Print the stack trace with KERN_EMERG - it should be always visible. Playing with console_loglevel is a bad idea as there may be more messages printed than wanted. Also the stack trace might be not printed at all if printk() was deferred and console_loglevel was raised back before the trace got flushed. Unfortunately, after rebasing on commit 2277b492582d ("kdb: Fix stack crawling on 'running' CPUs that aren't the master"), kdb_show_stack() uses now kdb_dump_stack_on_cpu(), which for now won't be converted as it uses dump_stack() instead of show_stack(). Convert for now the branch that uses show_stack() and remove console_loglevel exercise from that case. Signed-off-by: Dmitry Safonov Signed-off-by: Andrew Morton Reviewed-by: Douglas Anderson Acked-by: Daniel Thompson Cc: Jason Wessel Link: http://lkml.kernel.org/r/20200418201944.482088-48-dima@arista.com Signed-off-by: Linus Torvalds