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 --- tools/memory-model/linux-kernel.bell | 99 ++++++++++++++++++++++++++++++++++++ 1 file changed, 99 insertions(+) create mode 100644 tools/memory-model/linux-kernel.bell (limited to 'tools/memory-model/linux-kernel.bell') diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell new file mode 100644 index 000000000..fe6599800 --- /dev/null +++ b/tools/memory-model/linux-kernel.bell @@ -0,0 +1,99 @@ +// SPDX-License-Identifier: GPL-2.0+ +(* + * Copyright (C) 2015 Jade Alglave , + * Copyright (C) 2016 Luc Maranget for Inria + * Copyright (C) 2017 Alan Stern , + * Andrea Parri + * + * An earlier version of this file appeared in the companion webpage for + * "Frightening small children and disconcerting grown-ups: Concurrency + * in the Linux kernel" by Alglave, Maranget, McKenney, Parri, and Stern, + * which appeared in ASPLOS 2018. + *) + +"Linux-kernel memory consistency model" + +enum Accesses = 'ONCE (*READ_ONCE,WRITE_ONCE*) || + 'RELEASE (*smp_store_release*) || + 'ACQUIRE (*smp_load_acquire*) || + 'NORETURN (* R of non-return RMW *) || + 'MB (*xchg(),cmpxchg(),...*) +instructions R[Accesses] +instructions W[Accesses] +instructions RMW[Accesses] + +enum Barriers = 'wmb (*smp_wmb*) || + 'rmb (*smp_rmb*) || + 'MB (*smp_mb*) || + 'barrier (*barrier*) || + 'rcu-lock (*rcu_read_lock*) || + 'rcu-unlock (*rcu_read_unlock*) || + 'sync-rcu (*synchronize_rcu*) || + 'before-atomic (*smp_mb__before_atomic*) || + 'after-atomic (*smp_mb__after_atomic*) || + 'after-spinlock (*smp_mb__after_spinlock*) || + 'after-unlock-lock (*smp_mb__after_unlock_lock*) || + 'after-srcu-read-unlock (*smp_mb__after_srcu_read_unlock*) +instructions F[Barriers] + + +(* + * Filter out syntactic annotations that do not provide the corresponding + * semantic ordering, such as Acquire on a store or Mb on a failed RMW. + *) +let FailedRMW = RMW \ (domain(rmw) | range(rmw)) +let Acquire = ACQUIRE \ W \ FailedRMW +let Release = RELEASE \ R \ FailedRMW +let Mb = MB \ FailedRMW +let Noreturn = NORETURN \ W + +(* SRCU *) +enum SRCU = 'srcu-lock || 'srcu-unlock || 'sync-srcu +instructions SRCU[SRCU] +(* All srcu events *) +let Srcu = Srcu-lock | Srcu-unlock | Sync-srcu + +(* Compute matching pairs of nested Rcu-lock and Rcu-unlock *) +let rcu-rscs = let rec + unmatched-locks = Rcu-lock \ domain(matched) + and unmatched-unlocks = Rcu-unlock \ range(matched) + and unmatched = unmatched-locks | unmatched-unlocks + and unmatched-po = [unmatched] ; po ; [unmatched] + and unmatched-locks-to-unlocks = + [unmatched-locks] ; po ; [unmatched-unlocks] + and matched = matched | (unmatched-locks-to-unlocks \ + (unmatched-po ; unmatched-po)) + in matched + +(* Validate nesting *) +flag ~empty Rcu-lock \ domain(rcu-rscs) as unmatched-rcu-lock +flag ~empty Rcu-unlock \ range(rcu-rscs) as unmatched-rcu-unlock + +(* Compute matching pairs of nested Srcu-lock and Srcu-unlock *) +let carry-srcu-data = (data ; [~ Srcu-unlock] ; rf)* +let srcu-rscs = ([Srcu-lock] ; carry-srcu-data ; data ; [Srcu-unlock]) & loc + +(* Validate nesting *) +flag ~empty Srcu-lock \ domain(srcu-rscs) as unmatched-srcu-lock +flag ~empty Srcu-unlock \ range(srcu-rscs) as unmatched-srcu-unlock +flag ~empty (srcu-rscs^-1 ; srcu-rscs) \ id as multiple-srcu-matches + +(* Check for use of synchronize_srcu() inside an RCU critical section *) +flag ~empty rcu-rscs & (po ; [Sync-srcu] ; po) as invalid-sleep + +(* Validate SRCU dynamic match *) +flag ~empty different-values(srcu-rscs) as srcu-bad-value-match + +(* Compute marked and plain memory accesses *) +let Marked = (~M) | IW | ONCE | RELEASE | ACQUIRE | MB | RMW | + LKR | LKW | UL | LF | RL | RU | Srcu-lock | Srcu-unlock +let Plain = M \ Marked + +(* Redefine dependencies to include those carried through plain accesses *) +let carry-dep = (data ; [~ Srcu-unlock] ; rfi)* +let addr = carry-dep ; addr +let ctrl = carry-dep ; ctrl +let data = carry-dep ; data + +flag ~empty (if "lkmmv2" then 0 else _) + as this-model-requires-variant-higher-than-lkmmv1 -- cgit v1.3.1