user/sven/linux.git/kernel/locking, branch v5.2.4

locking/lockdep: Fix merging of hlocks with non-zero references

2019-07-26T07:10:20Z

[ Upstream commit d9349850e188b8b59e5322fda17ff389a1c0cd7d ] The sequence static DEFINE_WW_CLASS(test_ww_class); struct ww_acquire_ctx ww_ctx; struct ww_mutex ww_lock_a; struct ww_mutex ww_lock_b; struct ww_mutex ww_lock_c; struct mutex lock_c; ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); ww_mutex_init(&ww_lock_c, &test_ww_class); mutex_init(&lock_c); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); ww_mutex_lock(&ww_lock_b, &ww_ctx); ww_mutex_lock(&ww_lock_c, &ww_ctx); mutex_unlock(&lock_c); (*) ww_mutex_unlock(&ww_lock_c); ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); ww_acquire_fini(&ww_ctx); (**) will trigger the following error in __lock_release() when calling mutex_release() at **: DEBUG_LOCKS_WARN_ON(depth <= 0) The problem is that the hlock merging happening at * updates the references for test_ww_class incorrectly to 3 whereas it should've updated it to 4 (representing all the instances for ww_ctx and ww_lock_[abc]). Fix this by updating the references during merging correctly taking into account that we can have non-zero references (both for the hlock that we merge into another hlock or for the hlock we are merging into). Signed-off-by: Imre Deak Signed-off-by: Peter Zijlstra (Intel) Cc: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Link: https://lkml.kernel.org/r/20190524201509.9199-2-imre.deak@intel.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

locking/lockdep: Fix OOO unlock when hlocks need merging

2019-07-26T07:10:20Z

[ Upstream commit 8c8889d8eaf4501ae4aaf870b6f8f55db5d5109a ] The sequence static DEFINE_WW_CLASS(test_ww_class); struct ww_acquire_ctx ww_ctx; struct ww_mutex ww_lock_a; struct ww_mutex ww_lock_b; struct mutex lock_c; struct mutex lock_d; ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); mutex_init(&lock_c); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); ww_mutex_lock(&ww_lock_b, &ww_ctx); mutex_unlock(&lock_c); (*) ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); ww_acquire_fini(&ww_ctx); triggers the following WARN in __lock_release() when doing the unlock at *: DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1); The problem is that the WARN check doesn't take into account the merging of ww_lock_a and ww_lock_b which results in decreasing curr->lockdep_depth by 2 not only 1. Note that the following sequence doesn't trigger the WARN, since there won't be any hlock merging. ww_acquire_init(&ww_ctx, &test_ww_class); ww_mutex_init(&ww_lock_a, &test_ww_class); ww_mutex_init(&ww_lock_b, &test_ww_class); mutex_init(&lock_c); mutex_init(&lock_d); ww_mutex_lock(&ww_lock_a, &ww_ctx); mutex_lock(&lock_c); mutex_lock(&lock_d); ww_mutex_lock(&ww_lock_b, &ww_ctx); mutex_unlock(&lock_d); ww_mutex_unlock(&ww_lock_b); ww_mutex_unlock(&ww_lock_a); mutex_unlock(&lock_c); ww_acquire_fini(&ww_ctx); In general both of the above two sequences are valid and shouldn't trigger any lockdep warning. Fix this by taking the decrement due to the hlock merging into account during lock release and hlock class re-setting. Merging can't happen during lock downgrading since there won't be a new possibility to merge hlocks in that case, so add a WARN if merging still happens then. Signed-off-by: Imre Deak Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Will Deacon Cc: ville.syrjala@linux.intel.com Link: https://lkml.kernel.org/r/20190524201509.9199-1-imre.deak@intel.com Signed-off-by: Ingo Molnar Signed-off-by: Sasha Levin

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 436

2019-06-05T15:37:17Z

Based on 1 normalized pattern(s): distributed under the terms of the gnu gpl version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 2 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Armijn Hemel Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531190115.032570679@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157

2019-05-30T18:26:37Z

Based on 3 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version [author] [graeme] [gregory] [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i] [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema] [hk] [hemahk]@[ti] [com] this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1105 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Richard Fontana Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de Signed-off-by: Greg Kroah-Hartman

locking/lock_events: Use this_cpu_add() when necessary

2019-05-24T21:17:18Z

The kernel test robot has reported that the use of __this_cpu_add() causes bug messages like: BUG: using __this_cpu_add() in preemptible [00000000] code: ... Given the imprecise nature of the count and the possibility of resetting the count and doing the measurement again, this is not really a big problem to use the unprotected __this_cpu_*() functions. To make the preemption checking code happy, the this_cpu_*() functions will be used if CONFIG_DEBUG_PREEMPT is defined. The imprecise nature of the locking counts are also documented with the suggestion that we should run the measurement a few times with the counts reset in between to get a better picture of what is going on under the hood. Fixes: a8654596f0371 ("locking/rwsem: Enable lock event counting") Suggested-by: Linus Torvalds Signed-off-by: Waiman Long Signed-off-by: Linus Torvalds

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 9

2019-05-21T09:28:40Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details you should have received a copy of the gnu general public license along with this program if not you can access it online at http www gnu org licenses gpl 2 0 html extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 1 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Kate Stewart Reviewed-by: Jilayne Lovejoy Reviewed-by: Steve Winslow Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190519154041.430943677@linutronix.de Signed-off-by: Greg Kroah-Hartman

treewide: Add SPDX license identifier for missed files

2019-05-21T08:50:45Z

Add SPDX license identifiers to all files which: - Have no license information of any form - Have EXPORT_.*_SYMBOL_GPL inside which was used in the initial scan/conversion to ignore the file These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

locking/rwsem: Prevent decrement of reader count before increment

2019-05-07T06:46:46Z

During my rwsem testing, it was found that after a down_read(), the reader count may occasionally become 0 or even negative. Consequently, a writer may steal the lock at that time and execute with the reader in parallel thus breaking the mutual exclusion guarantee of the write lock. In other words, both readers and writer can become rwsem owners simultaneously. The current reader wakeup code does it in one pass to clear waiter->task and put them into wake_q before fully incrementing the reader count. Once waiter->task is cleared, the corresponding reader may see it, finish the critical section and do unlock to decrement the count before the count is incremented. This is not a problem if there is only one reader to wake up as the count has been pre-incremented by 1. It is a problem if there are more than one readers to be woken up and writer can steal the lock. The wakeup was actually done in 2 passes before the following v4.9 commit: 70800c3c0cc5 ("locking/rwsem: Scan the wait_list for readers only once") To fix this problem, the wakeup is now done in two passes again. In the first pass, we collect the readers and count them. The reader count is then fully incremented. In the second pass, the waiter->task is then cleared and they are put into wake_q to be woken up later. Signed-off-by: Waiman Long Acked-by: Linus Torvalds Cc: Borislav Petkov Cc: Davidlohr Bueso Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Tim Chen Cc: Will Deacon Cc: huang ying Fixes: 70800c3c0cc5 ("locking/rwsem: Scan the wait_list for readers only once") Link: http://lkml.kernel.org/r/20190428212557.13482-2-longman@redhat.com Signed-off-by: Ingo Molnar

Merge tag 'arm64-mmiowb' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

2019-05-06T23:57:52Z

Pull mmiowb removal from Will Deacon: "Remove Mysterious Macro Intended to Obscure Weird Behaviours (mmiowb()) Remove mmiowb() from the kernel memory barrier API and instead, for architectures that need it, hide the barrier inside spin_unlock() when MMIO has been performed inside the critical section. The only relatively recent changes have been addressing review comments on the documentation, which is in a much better shape thanks to the efforts of Ben and Ingo. I was initially planning to split this into two pull requests so that you could run the coccinelle script yourself, however it's been plain sailing in linux-next so I've just included the whole lot here to keep things simple" * tag 'arm64-mmiowb' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (23 commits) docs/memory-barriers.txt: Update I/O section to be clearer about CPU vs thread docs/memory-barriers.txt: Fix style, spacing and grammar in I/O section arch: Remove dummy mmiowb() definitions from arch code net/ethernet/silan/sc92031: Remove stale comment about mmiowb() i40iw: Redefine i40iw_mmiowb() to do nothing scsi/qla1280: Remove stale comment about mmiowb() drivers: Remove explicit invocations of mmiowb() drivers: Remove useless trailing comments from mmiowb() invocations Documentation: Kill all references to mmiowb() riscv/mmiowb: Hook up mmwiob() implementation to asm-generic code powerpc/mmiowb: Hook up mmwiob() implementation to asm-generic code ia64/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() mips/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() sh/mmiowb: Add unconditional mmiowb() to arch_spin_unlock() m68k/io: Remove useless definition of mmiowb() nds32/io: Remove useless definition of mmiowb() x86/io: Remove useless definition of mmiowb() arm64/io: Remove useless definition of mmiowb() ARM/io: Remove useless definition of mmiowb() mmiowb: Hook up mmiowb helpers to spinlocks and generic I/O accessors ...

Merge tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

2019-05-06T23:42:54Z

Pull s390 updates from Martin Schwidefsky: - Support for kernel address space layout randomization - Add support for kernel image signature verification - Convert s390 to the generic get_user_pages_fast code - Convert s390 to the stack unwind API analog to x86 - Add support for CPU directed interrupts for PCI devices - Provide support for MIO instructions to the PCI base layer, this will allow the use of direct PCI mappings in user space code - Add the basic KVM guest ultravisor interface for protected VMs - Add AT_HWCAP bits for several new hardware capabilities - Update the CPU measurement facility counter definitions to SVN 6 - Arnds cleanup patches for his quest to get LLVM compiles working - A vfio-ccw update with bug fixes and support for halt and clear - Improvements for the hardware TRNG code - Another round of cleanup for the QDIO layer - Numerous cleanups and bug fixes * tag 's390-5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (98 commits) s390/vdso: drop unnecessary cc-ldoption s390: fix clang -Wpointer-sign warnigns in boot code s390: drop CONFIG_VIRT_TO_BUS s390: boot, purgatory: pass $(CLANG_FLAGS) where needed s390: only build for new CPUs with clang s390: simplify disabled_wait s390/ftrace: use HAVE_FUNCTION_GRAPH_RET_ADDR_PTR s390/unwind: introduce stack unwind API s390/opcodes: add missing instructions to the disassembler s390/bug: add entry size to the __bug_table section s390: use proper expoline sections for .dma code s390/nospec: rename assembler generated expoline thunks s390: add missing ENDPROC statements to assembler functions locking/lockdep: check for freed initmem in static_obj() s390/kernel: add support for kernel address space layout randomization (KASLR) s390/kernel: introduce .dma sections s390/sclp: do not use static sccbs s390/kprobes: use static buffer for insn_page s390/kernel: convert SYSCALL and PGM_CHECK handlers to .quad s390/kernel: build a relocatable kernel ...