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* kdb_sysctl_trap: suppress gcc -Warray-boundsRyan Libby2024-07-091-1/+1
| | | | | | | | | gcc diagnosed a dereference of 0x10 with -Warray-bounds, which is entirely sensible, except that this is a deliberate trap. Throw gcc off with a volatile pointer. Reviewed by: kib (previous version) Differential Revision: https://reviews.freebsd.org/D45917
* SCHEDULER_STOPPED(): Rely on a global variableOlivier Certner2024-01-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A commit from 2012 (5d7380f8e34f0083, r228424) introduced 'td_stopsched', on the ground that a global variable would cause all CPUs to have a copy of it in their cache, and consequently of all other variables sharing the same cache line. This is really a problem only if that cache line sees relatively frequent modifications. This was unlikely to be the case back then because nearby variables are almost never modified as well. In any case, today we have a new tool at our disposal to ensure that this variable goes into a read-mostly section containing frequently-accessed variables ('__read_frequently'). Most of the cache lines covering this section are likely to always be in every CPU cache. This makes the second reason stated in the commit message (ensuring the field is in the same cache line as some lock-related fields, since these are accessed in close proximity) moot, as well as the second order effect of requiring an additional line to be present in the cache (the one containing the new 'scheduler_stopped' boolean, see below). From a pure logical point of view, whether the scheduler is stopped is a global state and is certainly not a per-thread quality. Consequently, remove 'td_stopsched', which immediately frees a byte in 'struct thread'. Currently, the latter's size (and layout) stays unchanged, but some of the later re-orderings will probably benefit from this removal. Available bytes at the original position for 'td_stopsched' have been made explicit with the addition of the '_td_pad0' member. Store the global state in the new 'scheduler_stopped' boolean, which is annotated with '__read_frequently'. Replace uses of SCHEDULER_STOPPED_TD() with SCHEDULER_STOPPER() and remove the former as it is now unnecessary. Reviewed by: markj, kib Approved by: markj (mentor) MFC after: 2 weeks Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D43572
* sys: Remove $FreeBSD$: one-line .c patternWarner Losh2023-08-161-2/+0
| | | | Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/
* kdb: Permit a NULL thread credential in kdb_backend_permitted()Mark Johnston2023-08-021-3/+11
| | | | | | | | | | | | | Early during boot, thread0 runs with td->td_ucred == NULL. This is fixed up in proc0_init() at SI_SUB_INTRINSIC. If a panic occurs before then, rather than dereference a NULL pointer, simply allow the thread to enter KDB. Reported by: stevek Reviewed by: mhorne, stevek MFC after: 1 week Fixes: cab1056105e3 ("kdb: Modify securelevel policy") Differential Revision: https://reviews.freebsd.org/D41280
* Revert "Revert "tslog: Annotate some early boot functions""Colin Percival2023-06-051-0/+3
| | | | | | | | Now that <sys/tslog.h> is wrapped in #ifdef _KERNEL, it's safe to have tslog annotations in files which might be built from userland (i.e. in subr_boot.c, which is built as part of the boot loader). This reverts commit 59588a546f55523d6fd37ab42eb08b719311d7d6.
* Revert "tslog: Annotate some early boot functions"Colin Percival2023-06-041-3/+0
| | | | | | | | | | | | The change to subr_boot.c broke the libsa build because the TSLOG macros have their own definitions for the boot loader -- I didn't realize that the loader code used subr_boot.c. I'm currently testing a fix and I'll revert this revert once I'm satisfied that everything works, but I don't want to leave the tree broken for too long. This reverts commit 469cfa3c30ee7a5ddeb597d0a8c3e7cac909b27a.
* tslog: Annotate some early boot functionsColin Percival2023-06-041-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Booting an amd64 kernel on Firecracker with 1 CPU and 128 MB of RAM, hammer_time takes roughly 2740 us: * 55 us in xen_pvh_parse_preload_data * 20 us in boot_parse_cmdline_delim * 20 us in boot_env_to_howto * 15 us in identify_hypervisor * 1320 us in link_elf_reloc * 1310 us in relocate_file1 handling ef->rela * 25 us in init_param1 * 30 us in dpcpu_init * 355 us in initializecpu * 255 us in initializecpu calling load_cr4 * 425 us in getmemsize * 280 us in pmap_bootstrap * 205 us in create_pagetables * 10 us in init_param2 * 25 us in pci_early_quirks * 60 us in cninit * 90 us in kdb_init * 105 us in msgbufinit * 20 us in fpuinit * 205 us elsewhere in hammer_time Some of these are unavoidable (e.g. identify_hypervisor uses CPUID and load_cr4 loads the CR4 register, both of which trap to the hypervisor) but others may deserve attention. Sponsored by: https://www.patreon.com/cperciva Differential Revision: https://reviews.freebsd.org/D40325
* smp: Dynamically allocate the stoppcbs arrayMark Johnston2023-05-251-3/+3
| | | | | | | | | | | | | | This avoids bloating the kernel image when MAXCPU is large. A follow-up patch for kgdb and other kernel debuggers is needed since the stoppcbs symbol is now a pointer. Bump __FreeBSD_version so that debuggers can use osreldate to figure out how to handle stoppcbs. PR: 269572 MFC after: never Reviewed by: mjg, emaste Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D39806
* spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSDWarner Losh2023-05-121-1/+1
| | | | | | | | | The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch up to that fact and revert to their recommended match of BSD-2-Clause. Discussed with: pfg MFC After: 3 days Sponsored by: Netflix
* Add new privilege PRIV_KDB_SET_BACKENDStephen J. Kiernan2023-04-161-0/+6
| | | | | | | | | | | | Summary: Check for PRIV_KDB_SET_BACKEND before allowing a thread to change the KDB backend. Obtained from: Juniper Networks, Inc. Reviewers: sjg, emaste Subscribers: imp Differential Revision: https://reviews.freebsd.org/D39538
* kdb: Modify securelevel policyMark Johnston2023-03-301-8/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, sysctls which enable KDB in some way are flagged with CTLFLAG_SECURE, meaning that you can't modify them if securelevel > 0. This is so that KDB cannot be used to lower a running system's securelevel, see commit 3d7618d8bf0b7. However, the newer mac_ddb(4) restricts DDB operations which could be abused to lower securelevel while retaining some ability to gather useful debugging information. To enable the use of KDB (specifically, DDB) on systems with a raised securelevel, change the KDB sysctl policy: rather than relying on CTLFLAG_SECURE, add a check of the current securelevel to kdb_trap(). If the securelevel is raised, only pass control to the backend if MAC specifically grants access; otherwise simply check to see if mac_ddb vetoes the request, as before. Add a new secure sysctl, debug.kdb.enter_securelevel, to override this behaviour. That is, the sysctl lets one enter a KDB backend even with a raised securelevel, so long as it is set before the securelevel is raised. Reviewed by: mhorne, stevek MFC after: 1 month Sponsored by: Juniper Networks Sponsored by: Klara, Inc. Differential Revision: https://reviews.freebsd.org/D37122
* mac: kdb/ddb framework hooksMitchell Horne2022-07-181-0/+11
| | | | | | | | | | | | | | | | Add three simple hooks to the debugger allowing for a loaded MAC policy to intervene if desired: 1. Before invoking the kdb backend 2. Before ddb command registration 3. Before ddb command execution We extend struct db_command with a private pointer and two flag bits reserved for policy use. Reviewed by: markj Sponsored by: Juniper Networks, Inc. Sponsored by: Klara, Inc. Differential Revision: https://reviews.freebsd.org/D35370
* kdb: set kdb_why when entered via reboot and panicTom Jones2022-04-121-1/+3
| | | | | | | | Reviewed by: jhb Sponsored by: NetApp, Inc. Sponsored by: Klara, Inc. X-NetApp-PR: #74 Differential Revision: https://reviews.freebsd.org/D34551
* stack_zero is not needed before stack_saveEric van Gyzen2022-03-261-1/+0
| | | | | | | The man page was recently clarified to commit to this contract. MFC after: 1 week Sponsored by: Dell EMC Isilon
* Restore variable aliasing in the context of cpu set operationsStefan Eßer2022-01-011-1/+2
| | | | | A simplification of set operations removed side-effects of the previous code, which are restored by this commit.
* Make CPU_SET macros compliant with other implementationsStefan Eßer2021-12-301-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The introduction of <sched.h> improved compatibility with some 3rd party software, but caused the configure scripts of some ports to assume that they were run in a GLIBC compatible environment. Parts of sched.h were made conditional on -D_WITH_CPU_SET_T being added to ports, but there still were compatibility issues due to invalid assumptions made in autoconfigure scripts. The differences between the FreeBSD version of macros like CPU_AND, CPU_OR, etc. and the GLIBC versions was in the number of arguments: FreeBSD used a 2-address scheme (one source argument is also used as the destination of the operation), while GLIBC uses a 3-adderess scheme (2 source operands and a separately passed destination). The GLIBC scheme provides a super-set of the functionality of the FreeBSD macros, since it does not prevent passing the same variable as source and destination arguments. In code that wanted to preserve both source arguments, the FreeBSD macros required a temporary copy of one of the source arguments. This patch set allows to unconditionally provide functions and macros expected by 3rd party software written for GLIBC based systems, but breaks builds of externally maintained sources that use any of the following macros: CPU_AND, CPU_ANDNOT, CPU_OR, CPU_XOR. One contributed driver (contrib/ofed/libmlx5) has been patched to support both the old and the new CPU_OR signatures. If this commit is merged to -STABLE, the version test will have to be extended to cover more ranges. Ports that have added -D_WITH_CPU_SET_T to build on -CURRENT do no longer require that option. The FreeBSD version has been bumped to 1400046 to reflect this incompatible change. Reviewed by: kib MFC after: 2 weeks Relnotes: yes Differential Revision: https://reviews.freebsd.org/D33451
* kdb: Handle process enumeration before procinit()Mitchell Horne2021-08-111-0/+6
| | | | | | | | | | | | | | | | | Make kdb_thr_first() and kdb_thr_next() return sane values if the allproc list and pidhashtbl haven't been initialized yet. This can happen if the debugger is entered very early on, for example with the '-d' boot flag. This allows remote gdb to attach at such a time, and fixes some ddb commands like 'show threads'. Be explicit about the static initialization of these variables. This part has no functional change. Reviewed by: markj, imp (previous version) MFC after: 3 days Differential Revision: https://reviews.freebsd.org/D31495
* sysctl: improve debug.kdb.panic_str descriptionWarner Losh2021-01-091-1/+1
| | | | | | Improve the wording for this sysctl. Submitted by: rpokala@
* sysctl: implement debug.kdb.panic_strWarner Losh2021-01-081-0/+20
| | | | | | | | | | | | | | | | This is just like debug.kdb.panic, except the string that's passed in is reported in the panic message. This allows people with automated systems to collect kernel panics over a large fleet of machines to flag panics better. Strings like "Warner look at this hang" or "see JIRA ABC-1234 for details" allow these automated systems to route the forced panic to the appropriate engineers like you can with other types of panics. Other users are likely possible. Relnotes: Yes Sponsored by: Netflix Reviewed by: allanjude (earlier version) Suggestions from review folded in by: 0mp, emaste, lwhsu Differential Revision: https://reviews.freebsd.org/D28041
* Don't check P_INMEM in kdb_thr_*().John Baldwin2021-01-011-8/+7
| | | | | | | | | | Not all debugger operations that enumerate threads require thread stacks to be resident in memory to be useful. Instead, push P_INMEM checks (if needed) into callers. Reviewed by: kib Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D27827
* Enumerate processes via the pid hash table in kdb_thr_*().John Baldwin2021-01-011-15/+24
| | | | | | | | | | Processes part way through exit1() are not included in allproc. Using allproc to enumerate processes prevented getting the stack trace of a thread in this part of exit1() via ddb. Reviewed by: kib Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D27826
* Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)Pawel Biernacki2020-02-261-15/+25
| | | | | | | | | | | | | | | | | | | r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are still not MPSAFE (or already are but aren’t properly marked). Use it in preparation for a general review of all nodes. This is non-functional change that adds annotations to SYSCTL_NODE and SYSCTL_PROC nodes using one of the soon-to-be-required flags. Mark all obvious cases as MPSAFE. All entries that haven't been marked as MPSAFE before are by default marked as NEEDGIANT Approved by: kib (mentor, blanket) Commented by: kib, gallatin, melifaro Differential Revision: https://reviews.freebsd.org/D23718 Notes: svn path=/head/; revision=358333
* Reimplement stack capture of running threads on i386 and amd64.Mark Johnston2020-01-311-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | After r355784 the td_oncpu field is no longer synchronized by the thread lock, so the stack capture interrupt cannot be delievered precisely. Fix this using a loop which drops the thread lock and restarts if the wrong thread was sampled from the stack capture interrupt handler. Change the implementation to use a regular interrupt instead of an NMI. Now that we drop the thread lock, there is no advantage to the latter. Simplify the KPIs. Remove stack_save_td_running() and add a return value to stack_save_td(). On platforms that do not support stack capture of running threads, stack_save_td() returns EOPNOTSUPP. If the target thread is running in user mode, stack_save_td() returns EBUSY. Reviewed by: kib Reported by: mjg, pho Tested by: pho Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D23355 Notes: svn path=/head/; revision=357334
* Remove duplicated empty lines from kern/*.cMateusz Guzik2020-01-301-1/+0
| | | | | | | No functional changes. Notes: svn path=/head/; revision=357312
* bitset: rename confusing macro NAND to ANDNOTRyan Libby2019-12-131-1/+1
| | | | | | | | | | | | | | | | s/BIT_NAND/BIT_ANDNOT/, and for CPU and DOMAINSET too. The actual implementation is "and not" (or "but not"), i.e. A but not B. Fortunately this does appear to be what all existing callers want. Don't supply a NAND (not (A and B)) operation at this time. Discussed with: jeff Reviewed by: cem Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D22791 Notes: svn path=/head/; revision=355709
* Implement NetGDB(4)Conrad Meyer2019-10-171-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NetGDB(4) is a component of a system using a panic-time network stack to remotely debug crashed FreeBSD kernels over the network, instead of traditional serial interfaces. There are three pieces in the complete NetGDB system. First, a dedicated proxy server must be running to accept connections from both NetGDB and gdb(1), and pass bidirectional traffic between the two protocols. Second, the NetGDB client is activated much like ordinary 'gdb' and similarly to 'netdump' in ddb(4) after a panic. Like other debugnet(4) clients (netdump(4)), the network interface on the route to the proxy server must be online and support debugnet(4). Finally, the remote (k)gdb(1) uses 'target remote <proxy>:<port>' (like any other TCP remote) to connect to the proxy server. The NetGDB v1 protocol speaks the literal GDB remote serial protocol, and uses a 1:1 relationship between GDB packets and sequences of debugnet packets (fragmented by MTU). There is no encryption utilized to keep debugging sessions private, so this is only appropriate for local segments or trusted networks. Submitted by: John Reimer <john.reimer AT emc.com> (earlier version) Discussed some with: emaste, markj Relnotes: sure Differential Revision: https://reviews.freebsd.org/D21568 Notes: svn path=/head/; revision=353700
* Always stop the scheduler when entering kdbEric van Gyzen2018-10-301-6/+6
| | | | | | | | | | | | | | | | | Set curthread->td_stopsched when entering kdb via any vector. Previously, it was only set when entering via panic, so when entering kdb another way, mutexes and such were still "live", and an attempt to lock an already locked mutex would panic. Reviewed by: kib, cem Discussed with: jhb Tested by: pho MFC after: 2 months Sponsored by: Dell EMC Isilon Differential Revision: https://reviews.freebsd.org/D17687 Notes: svn path=/head/; revision=339917
* Instead of using hand-rolled loops where not needed switch themBjoern A. Zeeb2018-06-201-6/+2
| | | | | | | | | | | | to FOREACH_PROC_IN_SYSTEM() to have a single pattern to look for. Reviewed by: kib MFC after: 2 weeks Sponsored by: iXsystems, Inc. Differential Revision: https://reviews.freebsd.org/D15916 Notes: svn path=/head/; revision=335441
* kdb_trap: Fix use of uninitialized dataEric van Gyzen2018-05-261-2/+3
| | | | | | | | | | | | In some cases, other_cpus was used without being initialized. Thankfully, it was harmless. Reported by: Coverity CID: 1385265 Sponsored by: Dell EMC Notes: svn path=/head/; revision=334238
* KDB: restart only CPUs stopped by KDBWojciech Macek2018-01-181-1/+3
| | | | | | | | | | | | | | There is a case when not all CPUs went online. In that situation, restart only APs which were operational before entering KDB. Created by: Wojciech Macek <wma@semihalf.com> Obtained from: Semihalf Reviewed by: nwhitehorn Differential revision: https://reviews.freebsd.org/D13949 Sponsored by: QCM Technologies Notes: svn path=/head/; revision=328110
* Add sysctl debug.kdb.stack_overflow to conveniently test kernelKonstantin Belousov2018-01-131-0/+35
| | | | | | | | | | handling of the kstack overflow. Sponsored by: The FreeBSD Foundation MFC after: 1 week Notes: svn path=/head/; revision=327917
* Implement 'domainset', a cpuset based NUMA policy mechanism. This allowsJeff Roberson2018-01-121-0/+1
| | | | | | | | | | | | | | | | | | | userspace to control NUMA policy administratively and programmatically. Implement domainset based iterators in the page layer. Remove the now legacy numa_* syscalls. Cleanup some header polution created by having seq.h in proc.h. Reviewed by: markj, kib Discussed with: alc Tested by: pho Sponsored by: Netflix, Dell/EMC Isilon Differential Revision: https://reviews.freebsd.org/D13403 Notes: svn path=/head/; revision=327895
* Fix several noticed style issues.Alexey Dokuchaev2017-11-291-8/+1
| | | | | | | | Reviewed by: bde Approved by: bapt Notes: svn path=/head/; revision=326364
* Make kdb_reenter() silent when explicitly called from db_error().Edward Tomasz Napierala2017-11-281-0/+11
| | | | | | | | | | | | | This removes the useless backtrace on various ddb(4) user errors. Reviewed by: jhb@ Obtained from: CheriBSD MFC after: 2 weeks Sponsored by: DARPA, AFRL Differential Revision: https://reviews.freebsd.org/D13212 Notes: svn path=/head/; revision=326314
* sys/kern: adoption of SPDX licensing ID tags.Pedro F. Giffuni2017-11-271-0/+2
| | | | | | | | | | | | | | | Mainly focus on files that use BSD 2-Clause license, however the tool I was using misidentified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts. Notes: svn path=/head/; revision=326271
* Change kdb_active type to u_char.Mateusz Guzik2017-10-221-1/+1
| | | | | | | | | | Fixes warnings from gcc and keeps the small size. Perhaps nesting should be moved to another variablle. Reported by: ngie Notes: svn path=/head/; revision=324863
* Clean up trailing whitespace in kdb_thr_ctx(..)Enji Cooper2017-10-221-3/+3
| | | | | | | MFC after: 1 week Notes: svn path=/head/; revision=324862
* Mark kdb_active as __read_frequently and switch to bool to eat less space.Mateusz Guzik2017-10-201-1/+1
| | | | Notes: svn path=/head/; revision=324789
* Fix multiple incorrect SYSCTL arguments in the kernel:Hans Petter Selasky2014-10-211-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Wrong integer type was specified. - Wrong or missing "access" specifier. The "access" specifier sometimes included the SYSCTL type, which it should not, except for procedural SYSCTL nodes. - Logical OR where binary OR was expected. - Properly assert the "access" argument passed to all SYSCTL macros, using the CTASSERT macro. This applies to both static- and dynamically created SYSCTLs. - Properly assert the the data type for both static and dynamic SYSCTLs. In the case of static SYSCTLs we only assert that the data pointed to by the SYSCTL data pointer has the correct size, hence there is no easy way to assert types in the C language outside a C-function. - Rewrote some code which doesn't pass a constant "access" specifier when creating dynamic SYSCTL nodes, which is now a requirement. - Updated "EXAMPLES" section in SYSCTL manual page. MFC after: 3 days Sponsored by: Mellanox Technologies Notes: svn path=/head/; revision=273377
* Pull in r267961 and r267973 again. Fix for issues reported will follow.Hans Petter Selasky2014-06-281-4/+2
| | | | Notes: svn path=/head/; revision=267992
* Revert r267961, r267973:Glen Barber2014-06-271-2/+4
| | | | | | | | | | | | | These changes prevent sysctl(8) from returning proper output, such as: 1) no output from sysctl(8) 2) erroneously returning ENOMEM with tools like truss(1) or uname(1) truss: can not get etype: Cannot allocate memory Notes: svn path=/head/; revision=267985
* Extend the meaning of the CTLFLAG_TUN flag to automatically check ifHans Petter Selasky2014-06-271-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | there is an environment variable which shall initialize the SYSCTL during early boot. This works for all SYSCTL types both statically and dynamically created ones, except for the SYSCTL NODE type and SYSCTLs which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to be used in the case a tunable sysctl has a custom initialisation function allowing the sysctl to still be marked as a tunable. The kernel SYSCTL API is mostly the same, with a few exceptions for some special operations like iterating childrens of a static/extern SYSCTL node. This operation should probably be made into a factored out common macro, hence some device drivers use this. The reason for changing the SYSCTL API was the need for a SYSCTL parent OID pointer and not only the SYSCTL parent OID list pointer in order to quickly generate the sysctl path. The motivation behind this patch is to avoid parameter loading cludges inside the OFED driver subsystem. Instead of adding special code to the OFED driver subsystem to post-load tunables into dynamically created sysctls, we generalize this in the kernel. Other changes: - Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask" to "hw.pcic.intr_mask". - Removed redundant TUNABLE statements throughout the kernel. - Some minor code rewrites in connection to removing not needed TUNABLE statements. - Added a missing SYSCTL_DECL(). - Wrapped two very long lines. - Avoid malloc()/free() inside sysctl string handling, in case it is called to initialize a sysctl from a tunable, hence malloc()/free() is not ready when sysctls from the sysctl dataset are registered. - Bumped FreeBSD version to indicate SYSCTL API change. MFC after: 2 weeks Sponsored by: Mellanox Technologies Notes: svn path=/head/; revision=267961
* When reentering kdb, typically due to a bug causing trap or assert inKonstantin Belousov2013-10-271-0/+2
| | | | | | | | | | | | | | | the code executed in the context of debugger, do not be ashamed to inform loudly about the re-entry. Also, print the backtrace before obliterating current stack with longjmp, allowing the operator to see a place which caused the bug. The change should make it less mysterious debugging the ddb itself. Sponsored by: The FreeBSD Foundation MFC after: 1 week Notes: svn path=/head/; revision=257214
* - Extend the KDB interface to add a per-debugger callback to print aJohn Baldwin2012-04-121-1/+26
| | | | | | | | | | | | | | backtrace for an arbitrary thread (rather than the calling thread). A kdb_backtrace_thread() wrapper function uses the configured debugger if possible, otherwise it falls back to using stack(9) if that is available. - Replace a direct call to db_trace_thread() in propagate_priority() with a call to kdb_backtrace_thread() instead. MFC after: 1 week Notes: svn path=/head/; revision=234190
* introduce cngrab/cnungrab stub calls in some places where they make senseAndriy Gapon2011-12-171-0/+5
| | | | | | | MFC after: 2 months Notes: svn path=/head/; revision=228632
* panic: add a switch and infrastructure for stopping other CPUs in SMP caseAndriy Gapon2011-12-111-10/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Historical behavior of letting other CPUs merily go on is a default for time being. The new behavior can be switched on via kern.stop_scheduler_on_panic tunable and sysctl. Stopping of the CPUs has (at least) the following benefits: - more of the system state at panic time is preserved intact - threads and interrupts do not interfere with dumping of the system state Only one thread runs uninterrupted after panic if stop_scheduler_on_panic is set. That thread might call code that is also used in normal context and that code might use locks to prevent concurrent execution of certain parts. Those locks might be held by the stopped threads and would never be released. To work around this issue, it was decided that instead of explicit checks for panic context, we would rather put those checks inside the locking primitives. This change has substantial portions written and re-written by attilio and kib at various times. Other changes are heavily based on the ideas and patches submitted by jhb and mdf. bde has provided many insights into the details and history of the current code. The new behavior may cause problems for systems that use a USB keyboard for interfacing with system console. This is because of some unusual locking patterns in the ukbd code which have to be used because on one hand ukbd is below syscons, but on the other hand it has to interface with other usb code that uses regular mutexes/Giant for its concurrency protection. Dumping to USB-connected disks may also be affected. PR: amd64/139614 (at least) In cooperation with: attilio, jhb, kib, mdf Discussed with: arch@, bde Tested by: Eugene Grosbein <eugen@grosbein.net>, gnn, Steven Hartland <killing@multiplay.co.uk>, glebius, Andrew Boyer <aboyer@averesystems.com> (various versions of the patch) MFC after: 3 months (or never) Notes: svn path=/head/; revision=228424
* Mark all SYSCTL_NODEs static that have no corresponding SYSCTL_DECLs.Ed Schouten2011-11-071-1/+1
| | | | | | | | | The SYSCTL_NODE macro defines a list that stores all child-elements of that node. If there's no SYSCTL_DECL macro anywhere else, there's no reason why it shouldn't be static. Notes: svn path=/head/; revision=227309
* Disallow various debug.kdb sysctl's when securelevel is raised.David E. O'Brien2011-10-071-9/+14
| | | | | | | PR: 161350 Notes: svn path=/head/; revision=226089
* Revert r225372:Attilio Rao2011-09-271-14/+0
| | | | | | | | | | | | | | | | | wdog_kern_pat() acquires eventhandler mutex, thus it cannot work in kernel context (from where kdb_trap() runs). The right way to fix this is both offering the cpu-stop-on-panic-and-skip-locking logic and also a context for KDB to officially run. We can re-enable this (or a similar) improvement when these 2 patches hit the tree. Sponsored by: Sandvine Incorporated Discussed with: emaste, rstone MFC after: immediately Notes: svn path=/head/; revision=225794
* Interrupts are disabled/enabled when entering and exiting the KDB context.Attilio Rao2011-09-041-0/+14
| | | | | | | | | | | | | | | | | | While this is generally good, it brings along a serie of problems, like clocks going off sync and in presence of SW_WATCHDOG, watchdogs firing without a good reason (missed hardclock wdog ticks update). Fix the latter by kicking the watchdog just before to re-enable the interrupts. Also, while here, not rely on users to stop the watchdog manually when entering DDB but do that when entering KDB context. Sponsored by: Sandvine Incorporated Reviewed by: emaste, rstone Approved by: re (kib) MFC after: 1 week Notes: svn path=/head/; revision=225372
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