diff options
| author | Andi Kleen <ak@linux.intel.com> | 2017-11-17 15:27:06 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-11-17 16:10:01 -0800 |
| commit | aaf5dcfb223617ac2d16113e4b500199c65689de (patch) | |
| tree | 708dbc2baef2f18cfb368b2e785642f6a4ece283 | |
| parent | b1fca27d384e8418aac84b39f6f5179aecc1b64f (diff) | |
| download | lwn-aaf5dcfb223617ac2d16113e4b500199c65689de.tar.gz lwn-aaf5dcfb223617ac2d16113e4b500199c65689de.zip | |
kernel debug: support resetting WARN_ONCE for all architectures
Some architectures store the WARN_ONCE state in the flags field of the
bug_entry. Clear that one too when resetting once state through
/sys/kernel/debug/clear_warn_once
Pointed out by Michael Ellerman
Improves the earlier patch that add clear_warn_once.
[ak@linux.intel.com: add a missing ifdef CONFIG_MODULES]
Link: http://lkml.kernel.org/r/20171020170633.9593-1-andi@firstfloor.org
[akpm@linux-foundation.org: fix unused var warning]
[akpm@linux-foundation.org: Use 0200 for clear_warn_once file, per mpe]
[akpm@linux-foundation.org: clear BUGFLAG_DONE in clear_once_table(), per mpe]
Link: http://lkml.kernel.org/r/20171019204642.7404-1-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | include/linux/bug.h | 5 | ||||
| -rw-r--r-- | kernel/panic.c | 3 | ||||
| -rw-r--r-- | lib/bug.c | 23 |
3 files changed, 30 insertions, 1 deletions
diff --git a/include/linux/bug.h b/include/linux/bug.h index da4231c905c8..fe5916550da8 100644 --- a/include/linux/bug.h +++ b/include/linux/bug.h @@ -43,6 +43,8 @@ enum bug_trap_type report_bug(unsigned long bug_addr, struct pt_regs *regs); /* These are defined by the architecture */ int is_valid_bugaddr(unsigned long addr); +void generic_bug_clear_once(void); + #else /* !CONFIG_GENERIC_BUG */ static inline enum bug_trap_type report_bug(unsigned long bug_addr, @@ -51,6 +53,9 @@ static inline enum bug_trap_type report_bug(unsigned long bug_addr, return BUG_TRAP_TYPE_BUG; } + +static inline void generic_bug_clear_once(void) {} + #endif /* CONFIG_GENERIC_BUG */ /* diff --git a/kernel/panic.c b/kernel/panic.c index 672a91dc20fe..67cebf2a3b67 100644 --- a/kernel/panic.c +++ b/kernel/panic.c @@ -595,6 +595,7 @@ EXPORT_SYMBOL(warn_slowpath_null); static int clear_warn_once_set(void *data, u64 val) { + generic_bug_clear_once(); memset(__start_once, 0, __end_once - __start_once); return 0; } @@ -607,7 +608,7 @@ DEFINE_SIMPLE_ATTRIBUTE(clear_warn_once_fops, static __init int register_warn_debugfs(void) { /* Don't care about failure */ - debugfs_create_file("clear_warn_once", 0644, NULL, + debugfs_create_file("clear_warn_once", 0200, NULL, NULL, &clear_warn_once_fops); return 0; } diff --git a/lib/bug.c b/lib/bug.c index 1e094408c893..f66be6bf6206 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -196,3 +196,26 @@ enum bug_trap_type report_bug(unsigned long bugaddr, struct pt_regs *regs) return BUG_TRAP_TYPE_BUG; } + +static void clear_once_table(struct bug_entry *start, struct bug_entry *end) +{ + struct bug_entry *bug; + + for (bug = start; bug < end; bug++) + bug->flags &= ~BUGFLAG_DONE; +} + +void generic_bug_clear_once(void) +{ +#ifdef CONFIG_MODULES + struct module *mod; + + rcu_read_lock_sched(); + list_for_each_entry_rcu(mod, &module_bug_list, bug_list) + clear_once_table(mod->bug_table, + mod->bug_table + mod->num_bugs); + rcu_read_unlock_sched(); +#endif + + clear_once_table(__start___bug_table, __stop___bug_table); +} |