From 7e61560628d17ea6b1d8ee370f6d42694cff8758 Mon Sep 17 00:00:00 2001 From: Ulises Mendez Martinez Date: Fri, 4 Sep 2026 15:07:09 +0000 Subject: objtool: Validate disassembler headers in libopcodes probe commit 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") tested for libopcodes availability by linking a test snippet with a forward declaration of disassemble_init_for_target(). However, testing symbol linkage with an extern declaration only verifies the presence of the library (.so/.a) and bypasses checking for development headers (binutils-dev). On systems where libopcodes is present without development headers installed, the probe succeeds, enabling BUILD_DISAS. Subsequent compilation of objtool then fails: fatal error: 'bfd.h' file not found 113 | #include Additionally, the probe invokes $(HOSTCC) without $(HOSTCFLAGS), ignoring any sysroot or include flags specified for the host compiler. Fix this by including and directly in the test snippet, passing $(HOSTCFLAGS) so host compiler options are respected, and defining PACKAGE="objtool" to satisfy the configuration check in . Fixes: 3f2de814c059 ("objtool: Fix libopcodes linking with static libraries") Fixes: 436326bc525d ("objtool: fix build failure due to missing libopcodes check") Reported-by: Alice Ryhl Assisted-by: Antigravity:Gemini-Next Signed-off-by: Ulises Mendez Martinez Link: https://patch.msgid.link/20260904150710.2997558-1-umendez@google.com Signed-off-by: Josh Poimboeuf --- lib/once.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 lib/once.c (limited to 'lib/once.c') diff --git a/lib/once.c b/lib/once.c new file mode 100644 index 000000000..d801bfa94 --- /dev/null +++ b/lib/once.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +struct once_work { + struct work_struct work; + struct static_key_true *key; + struct module *module; +}; + +static void once_deferred(struct work_struct *w) +{ + struct once_work *work; + + work = container_of(w, struct once_work, work); + BUG_ON(!static_key_enabled(work->key)); + static_branch_disable(work->key); + module_put(work->module); + kfree(work); +} + +static void once_disable_jump(struct static_key_true *key, struct module *mod) +{ + struct once_work *w; + + w = kmalloc_obj(*w, GFP_ATOMIC); + if (!w) + return; + + INIT_WORK(&w->work, once_deferred); + w->key = key; + w->module = mod; + __module_get(mod); + schedule_work(&w->work); +} + +static DEFINE_SPINLOCK(once_lock); + +bool __do_once_start(bool *done, unsigned long *flags) + __acquires(once_lock) +{ + spin_lock_irqsave(&once_lock, *flags); + if (*done) { + spin_unlock_irqrestore(&once_lock, *flags); + /* Keep sparse happy by restoring an even lock count on + * this lock. In case we return here, we don't call into + * __do_once_done but return early in the DO_ONCE() macro. + */ + __acquire(once_lock); + return false; + } + + return true; +} +EXPORT_SYMBOL(__do_once_start); + +void __do_once_done(bool *done, struct static_key_true *once_key, + unsigned long *flags, struct module *mod) + __releases(once_lock) +{ + *done = true; + spin_unlock_irqrestore(&once_lock, *flags); + once_disable_jump(once_key, mod); +} +EXPORT_SYMBOL(__do_once_done); + +static DEFINE_MUTEX(once_mutex); + +bool __do_once_sleepable_start(bool *done) + __acquires(once_mutex) +{ + mutex_lock(&once_mutex); + if (*done) { + mutex_unlock(&once_mutex); + /* Keep sparse happy by restoring an even lock count on + * this mutex. In case we return here, we don't call into + * __do_once_done but return early in the DO_ONCE_SLEEPABLE() macro. + */ + __acquire(once_mutex); + return false; + } + + return true; +} +EXPORT_SYMBOL(__do_once_sleepable_start); + +void __do_once_sleepable_done(bool *done, struct static_key_true *once_key, + struct module *mod) + __releases(once_mutex) +{ + *done = true; + mutex_unlock(&once_mutex); + static_branch_disable(once_key); +} +EXPORT_SYMBOL(__do_once_sleepable_done); -- cgit v1.3.1