From e319e1fbd9d42420ab6eec0bfd75eb9ad7ca63b1 Mon Sep 17 00:00:00 2001 From: Byungchul Park Date: Wed, 25 Oct 2017 17:56:05 +0900 Subject: block, locking/lockdep: Assign a lock_class per gendisk used for wait_for_completion() Darrick posted the following warning and Dave Chinner analyzed it: > ====================================================== > WARNING: possible circular locking dependency detected > 4.14.0-rc1-fixes #1 Tainted: G W > ------------------------------------------------------ > loop0/31693 is trying to acquire lock: > (&(&ip->i_mmaplock)->mr_lock){++++}, at: [] xfs_ilock+0x23c/0x330 [xfs] > > but now in release context of a crosslock acquired at the following: > ((complete)&ret.event){+.+.}, at: [] submit_bio_wait+0x7f/0xb0 > > which lock already depends on the new lock. > > the existing dependency chain (in reverse order) is: > > -> #2 ((complete)&ret.event){+.+.}: > lock_acquire+0xab/0x200 > wait_for_completion_io+0x4e/0x1a0 > submit_bio_wait+0x7f/0xb0 > blkdev_issue_zeroout+0x71/0xa0 > xfs_bmapi_convert_unwritten+0x11f/0x1d0 [xfs] > xfs_bmapi_write+0x374/0x11f0 [xfs] > xfs_iomap_write_direct+0x2ac/0x430 [xfs] > xfs_file_iomap_begin+0x20d/0xd50 [xfs] > iomap_apply+0x43/0xe0 > dax_iomap_rw+0x89/0xf0 > xfs_file_dax_write+0xcc/0x220 [xfs] > xfs_file_write_iter+0xf0/0x130 [xfs] > __vfs_write+0xd9/0x150 > vfs_write+0xc8/0x1c0 > SyS_write+0x45/0xa0 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #1 (&xfs_nondir_ilock_class){++++}: > lock_acquire+0xab/0x200 > down_write_nested+0x4a/0xb0 > xfs_ilock+0x263/0x330 [xfs] > xfs_setattr_size+0x152/0x370 [xfs] > xfs_vn_setattr+0x6b/0x90 [xfs] > notify_change+0x27d/0x3f0 > do_truncate+0x5b/0x90 > path_openat+0x237/0xa90 > do_filp_open+0x8a/0xf0 > do_sys_open+0x11c/0x1f0 > entry_SYSCALL_64_fastpath+0x1f/0xbe > > -> #0 (&(&ip->i_mmaplock)->mr_lock){++++}: > up_write+0x1c/0x40 > xfs_iunlock+0x1d0/0x310 [xfs] > xfs_file_fallocate+0x8a/0x310 [xfs] > loop_queue_work+0xb7/0x8d0 > kthread_worker_fn+0xb9/0x1f0 > > Chain exists of: > &(&ip->i_mmaplock)->mr_lock --> &xfs_nondir_ilock_class --> (complete)&ret.event > > Possible unsafe locking scenario by crosslock: > > CPU0 CPU1 > ---- ---- > lock(&xfs_nondir_ilock_class); > lock((complete)&ret.event); > lock(&(&ip->i_mmaplock)->mr_lock); > unlock((complete)&ret.event); > > *** DEADLOCK *** The warning is a false positive, caused by the fact that all wait_for_completion()s in submit_bio_wait() are waiting with the same lock class. However, some bios have nothing to do with others, for example in the case of loop devices, there's no direct connection between the bios of an upper device and the bios of a lower device(=loop device). The safest way to assign different lock classes to different devices is to do it for each gendisk. In other words, this patch assigns a lockdep_map per gendisk and uses it when initializing completion in submit_bio_wait(). Analyzed-by: Dave Chinner Reported-by: Darrick J. Wong Signed-off-by: Byungchul Park Reviewed-by: Jens Axboe Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: amir73il@gmail.com Cc: axboe@kernel.dk Cc: david@fromorbit.com Cc: hch@infradead.org Cc: idryomov@gmail.com Cc: johan@kernel.org Cc: johannes.berg@intel.com Cc: kernel-team@lge.com Cc: linux-block@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org Cc: linux-mm@kvack.org Cc: linux-xfs@vger.kernel.org Cc: oleg@redhat.com Cc: tj@kernel.org Link: http://lkml.kernel.org/r/1508921765-15396-10-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar --- include/linux/genhd.h | 22 ++++++++++++++++++++-- 1 file changed, 20 insertions(+), 2 deletions(-) (limited to 'include/linux/genhd.h') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index ea652bfcd675..19d18710546a 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -206,6 +206,7 @@ struct gendisk { #endif /* CONFIG_BLK_DEV_INTEGRITY */ int node_id; struct badblocks *bb; + struct lockdep_map lockdep_map; }; static inline struct gendisk *part_to_disk(struct hd_struct *part) @@ -590,8 +591,7 @@ extern void __delete_partition(struct percpu_ref *); extern void delete_partition(struct gendisk *, int); extern void printk_all_partitions(void); -extern struct gendisk *alloc_disk_node(int minors, int node_id); -extern struct gendisk *alloc_disk(int minors); +extern struct gendisk *__alloc_disk_node(int minors, int node_id); extern struct kobject *get_disk(struct gendisk *disk); extern void put_disk(struct gendisk *disk); extern void blk_register_region(dev_t devt, unsigned long range, @@ -615,6 +615,24 @@ extern ssize_t part_fail_store(struct device *dev, const char *buf, size_t count); #endif /* CONFIG_FAIL_MAKE_REQUEST */ +#define alloc_disk_node(minors, node_id) \ +({ \ + static struct lock_class_key __key; \ + const char *__name; \ + struct gendisk *__disk; \ + \ + __name = "(gendisk_completion)"#minors"("#node_id")"; \ + \ + __disk = __alloc_disk_node(minors, node_id); \ + \ + if (__disk) \ + lockdep_init_map(&__disk->lockdep_map, __name, &__key, 0); \ + \ + __disk; \ +}) + +#define alloc_disk(minors) alloc_disk_node(minors, NUMA_NO_NODE) + static inline int hd_ref_init(struct hd_struct *part) { if (percpu_ref_init(&part->ref, __delete_partition, 0, -- cgit v1.2.3 From b24413180f5600bcb3bb70fbed5cf186b60864bd Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Wed, 1 Nov 2017 15:07:57 +0100 Subject: License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman --- include/linux/genhd.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/genhd.h') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index ea652bfcd675..44790523057f 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_GENHD_H #define _LINUX_GENHD_H -- cgit v1.2.3 From 517bf3c306bad4fe0da631f90ae2ec40924dee2b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 2 Nov 2017 21:29:52 +0300 Subject: block: don't look at the struct device dev_t in disk_devt The hidden gendisks introduced in the next patch need to keep the dev field in their struct device empty so that udev won't try to create block device nodes for them. To support that rewrite disk_devt to look at the major and first_minor fields in the gendisk itself instead of looking into the struct device. Signed-off-by: Christoph Hellwig Reviewed-by: Johannes Thumshirn Reviewed-by: Hannes Reinecke Signed-off-by: Jens Axboe --- include/linux/genhd.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/genhd.h') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index ea652bfcd675..5c0ed5db33c2 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -234,7 +234,7 @@ static inline bool disk_part_scan_enabled(struct gendisk *disk) static inline dev_t disk_devt(struct gendisk *disk) { - return disk_to_dev(disk)->devt; + return MKDEV(disk->major, disk->first_minor); } static inline dev_t part_devt(struct hd_struct *part) -- cgit v1.2.3 From 8ddcd653257c18a669fcb75ee42c37054908e0d6 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 2 Nov 2017 21:29:53 +0300 Subject: block: introduce GENHD_FL_HIDDEN With this flag a driver can create a gendisk that can be used for I/O submission inside the kernel, but which is not registered as user facing block device. This will be useful for the NVMe multipath implementation. Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- include/linux/genhd.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/genhd.h') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 5c0ed5db33c2..93aae3476f58 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -140,6 +140,7 @@ struct hd_struct { #define GENHD_FL_NATIVE_CAPACITY 128 #define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 256 #define GENHD_FL_NO_PART_SCAN 512 +#define GENHD_FL_HIDDEN 1024 enum { DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */ -- cgit v1.2.3 From 67f2519fe2903c4041c0e94394d14d372fe51399 Mon Sep 17 00:00:00 2001 From: Greg Edwards Date: Tue, 24 Oct 2017 11:21:48 -0600 Subject: fs: guard_bio_eod() needs to consider partitions guard_bio_eod() needs to look at the partition capacity, not just the capacity of the whole device, when determining if truncation is necessary. [ 60.268688] attempt to access beyond end of device [ 60.268690] unknown-block(9,1): rw=0, want=67103509, limit=67103506 [ 60.268693] buffer_io_error: 2 callbacks suppressed [ 60.268696] Buffer I/O error on dev md1p7, logical block 4524305, async page read Fixes: 74d46992e0d9 ("block: replace bi_bdev with a gendisk pointer and partitions index") Cc: stable@vger.kernel.org # v4.13 Reviewed-by: Christoph Hellwig Signed-off-by: Greg Edwards Signed-off-by: Jens Axboe --- include/linux/genhd.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/genhd.h') diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 93aae3476f58..ca10cc292187 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -243,6 +243,7 @@ static inline dev_t part_devt(struct hd_struct *part) return part_to_dev(part)->devt; } +extern struct hd_struct *__disk_get_part(struct gendisk *disk, int partno); extern struct hd_struct *disk_get_part(struct gendisk *disk, int partno); static inline void disk_put_part(struct hd_struct *part) -- cgit v1.2.3