linux-stable.git/block, branch v4.19.166 Linux kernel stable tree block: factor out requeue handling from dispatch code 2020-12-30T10:25:45+00:00 Johannes Thumshirn johannes.thumshirn@wdc.com 2020-03-24T15:24:44+00:00 7894076fbc90e8c2528e339d50f0e669a6e7fc7a [ Upstream commit c92a41031a6d57395889b5c87cea359220a24d2a ] Factor out the requeue handling from the dispatch code, this will make subsequent addition of different requeueing schemes easier. Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit c92a41031a6d57395889b5c87cea359220a24d2a ]

Factor out the requeue handling from the dispatch code, this will make
subsequent addition of different requeueing schemes easier.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
blk-cgroup: Pre-allocate tree node on blkg_conf_prep 2020-11-10T11:35:59+00:00 Gabriel Krisman Bertazi krisman@collabora.com 2020-10-22T20:58:42+00:00 239aed5d2ecbfd381ca642f0a6bcb272c98408df [ Upstream commit f255c19b3ab46d3cad3b1b2e1036f4c926cb1d0c ] Similarly to commit 457e490f2b741 ("blkcg: allocate struct blkcg_gq outside request queue spinlock"), blkg_create can also trigger occasional -ENOMEM failures at the radix insertion because any allocation inside blkg_create has to be non-blocking, making it more likely to fail. This causes trouble for userspace tools trying to configure io weights who need to deal with this condition. This patch reduces the occurrence of -ENOMEMs on this path by preloading the radix tree element on a GFP_KERNEL context, such that we guarantee the later non-blocking insertion won't fail. A similar solution exists in blkcg_init_queue for the same situation. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f255c19b3ab46d3cad3b1b2e1036f4c926cb1d0c ]

Similarly to commit 457e490f2b741 ("blkcg: allocate struct blkcg_gq
outside request queue spinlock"), blkg_create can also trigger
occasional -ENOMEM failures at the radix insertion because any
allocation inside blkg_create has to be non-blocking, making it more
likely to fail.  This causes trouble for userspace tools trying to
configure io weights who need to deal with this condition.

This patch reduces the occurrence of -ENOMEMs on this path by preloading
the radix tree element on a GFP_KERNEL context, such that we guarantee
the later non-blocking insertion won't fail.

A similar solution exists in blkcg_init_queue for the same situation.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
blk-cgroup: Fix memleak on error path 2020-11-10T11:35:59+00:00 Gabriel Krisman Bertazi krisman@collabora.com 2020-10-22T20:58:41+00:00 6dba51828dfd31e326e6642727ede24c054a86fe [ Upstream commit 52abfcbd57eefdd54737fc8c2dc79d8f46d4a3e5 ] If new_blkg allocation raced with blk_policy change and blkg_lookup_check fails, new_blkg is leaked. Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 52abfcbd57eefdd54737fc8c2dc79d8f46d4a3e5 ]

If new_blkg allocation raced with blk_policy change and
blkg_lookup_check fails, new_blkg is leaked.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Revert "block: ratelimit handle_bad_sector() message" 2020-11-05T10:08:35+00:00 Greg Kroah-Hartman gregkh@linuxfoundation.org 2020-11-01T10:42:18+00:00 8dda141d0b16031e0b24d6fed46f69873e000f08 This reverts commit f86b9bf6228bb334fe1addcd566a658ecbd08f7e which is commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d upstream. Jari Ruusu writes: Above change "block: ratelimit handle_bad_sector() message" upstream commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d in 4.19.154 kernel is not completely OK. Removing casts from arguments 4 and 5 produces these compile warnings: ... For 64 bit systems it is only compile time cosmetic warning. For 32 bit system + CONFIG_LBDAF=n it introduces bugs: output formats are "%llu" and passed parameters are 32 bits. That is not OK. Upstream kernels have hardcoded 64 bit sector_t. In older stable trees sector_t can be either 64 or 32 bit. In other words, backport of above patch needs to keep those original casts. And Tetsuo Handa writes: Indeed, commit f4ac712e4fe00963 ("block: ratelimit handle_bad_sector() message") depends on commit 72deb455b5ec619f ("block: remove CONFIG_LBDAF") which was merged into 5.2 kernel. So let's revert it. Reported-by: Jari Ruusu <jariruusu@users.sourceforge.net> Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp> Cc: Christoph Hellwig <hch@lst.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
This reverts commit f86b9bf6228bb334fe1addcd566a658ecbd08f7e which is
commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d upstream.

Jari Ruusu writes:

	Above change "block: ratelimit handle_bad_sector() message"
	upstream commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d
	in 4.19.154 kernel is not completely OK.

	Removing casts from arguments 4 and 5 produces these compile warnings:

	...

	For 64 bit systems it is only compile time cosmetic warning. For 32 bit
	system + CONFIG_LBDAF=n it introduces bugs: output formats are "%llu" and
	passed parameters are 32 bits. That is not OK.

	Upstream kernels have hardcoded 64 bit sector_t. In older stable trees
	sector_t can be either 64 or 32 bit. In other words, backport of above patch
	needs to keep those original casts.

And Tetsuo Handa writes:
	Indeed, commit f4ac712e4fe00963 ("block: ratelimit handle_bad_sector() message")
	depends on commit 72deb455b5ec619f ("block: remove CONFIG_LBDAF") which was merged
	into 5.2 kernel.

So let's revert it.

Reported-by: Jari Ruusu <jariruusu@users.sourceforge.net>
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: ratelimit handle_bad_sector() message 2020-10-30T09:38:26+00:00 Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp 2020-10-08T13:37:23+00:00 f86b9bf6228bb334fe1addcd566a658ecbd08f7e [ Upstream commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d ] syzbot is reporting unkillable task [1], for the caller is failing to handle a corrupted filesystem image which attempts to access beyond the end of the device. While we need to fix the caller, flooding the console with handle_bad_sector() message is unlikely useful. [1] https://syzkaller.appspot.com/bug?id=f1f49fb971d7a3e01bd8ab8cff2ff4572ccf3092 Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit f4ac712e4fe009635344b9af5d890fe25fcc8c0d ]

syzbot is reporting unkillable task [1], for the caller is failing to
handle a corrupted filesystem image which attempts to access beyond
the end of the device. While we need to fix the caller, flooding the
console with handle_bad_sector() message is unlikely useful.

[1] https://syzkaller.appspot.com/bug?id=f1f49fb971d7a3e01bd8ab8cff2ff4572ccf3092

Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block: ensure bdi->io_pages is always initialized 2020-09-12T11:40:22+00:00 Jens Axboe axboe@kernel.dk 2020-08-31T17:20:02+00:00 732fd460bb72fd51607311009b7d474a6e0e47f3 [ Upstream commit de1b0ee490eafdf65fac9eef9925391a8369f2dc ] If a driver leaves the limit settings as the defaults, then we don't initialize bdi->io_pages. This means that file systems may need to work around bdi->io_pages == 0, which is somewhat messy. Initialize the default value just like we do for ->ra_pages. Cc: stable@vger.kernel.org Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting") Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit de1b0ee490eafdf65fac9eef9925391a8369f2dc ]

If a driver leaves the limit settings as the defaults, then we don't
initialize bdi->io_pages. This means that file systems may need to
work around bdi->io_pages == 0, which is somewhat messy.

Initialize the default value just like we do for ->ra_pages.

Cc: stable@vger.kernel.org
Fixes: 9491ae4aade6 ("mm: don't cap request size based on read-ahead setting")
Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
blk-mq: order adding requests to hctx->dispatch and checking SCHED_RESTART 2020-09-03T09:24:26+00:00 Ming Lei ming.lei@redhat.com 2020-08-17T10:01:15+00:00 77064570e4c3636da26f30ed28e4d132256424ec commit d7d8535f377e9ba87edbf7fbbd634ac942f3f54f upstream. SCHED_RESTART code path is relied to re-run queue for dispatch requests in hctx->dispatch. Meantime the SCHED_RSTART flag is checked when adding requests to hctx->dispatch. memory barriers have to be used for ordering the following two pair of OPs: 1) adding requests to hctx->dispatch and checking SCHED_RESTART in blk_mq_dispatch_rq_list() 2) clearing SCHED_RESTART and checking if there is request in hctx->dispatch in blk_mq_sched_restart(). Without the added memory barrier, either: 1) blk_mq_sched_restart() may miss requests added to hctx->dispatch meantime blk_mq_dispatch_rq_list() observes SCHED_RESTART, and not run queue in dispatch side or 2) blk_mq_dispatch_rq_list still sees SCHED_RESTART, and not run queue in dispatch side, meantime checking if there is request in hctx->dispatch from blk_mq_sched_restart() is missed. IO hang in ltp/fs_fill test is reported by kernel test robot: https://lkml.org/lkml/2020/7/26/77 Turns out it is caused by the above out-of-order OPs. And the IO hang can't be observed any more after applying this patch. Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers") Reported-by: kernel test robot <rong.a.chen@intel.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Bart Van Assche <bvanassche@acm.org> Cc: Christoph Hellwig <hch@lst.de> Cc: David Jeffery <djeffery@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit d7d8535f377e9ba87edbf7fbbd634ac942f3f54f upstream.

SCHED_RESTART code path is relied to re-run queue for dispatch requests
in hctx->dispatch. Meantime the SCHED_RSTART flag is checked when adding
requests to hctx->dispatch.

memory barriers have to be used for ordering the following two pair of OPs:

1) adding requests to hctx->dispatch and checking SCHED_RESTART in
blk_mq_dispatch_rq_list()

2) clearing SCHED_RESTART and checking if there is request in hctx->dispatch
in blk_mq_sched_restart().

Without the added memory barrier, either:

1) blk_mq_sched_restart() may miss requests added to hctx->dispatch meantime
blk_mq_dispatch_rq_list() observes SCHED_RESTART, and not run queue in
dispatch side

or

2) blk_mq_dispatch_rq_list still sees SCHED_RESTART, and not run queue
in dispatch side, meantime checking if there is request in
hctx->dispatch from blk_mq_sched_restart() is missed.

IO hang in ltp/fs_fill test is reported by kernel test robot:

	https://lkml.org/lkml/2020/7/26/77

Turns out it is caused by the above out-of-order OPs. And the IO hang
can't be observed any more after applying this patch.

Fixes: bd166ef183c2 ("blk-mq-sched: add framework for MQ capable IO schedulers")
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Jeffery <djeffery@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block: release bip in a right way in error path 2020-07-16T06:17:23+00:00 Chengguang Xu cgxu519@mykernel.net 2020-06-24T10:21:39+00:00 1d269061bb3823c9e744397713f42e9fa49576eb [ Upstream commit 0b8eb629a700c0ef15a437758db8255f8444e76c ] Release bip using kfree() in error path when that was allocated by kmalloc(). Signed-off-by: Chengguang Xu <cgxu519@mykernel.net> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 0b8eb629a700c0ef15a437758db8255f8444e76c ]

Release bip using kfree() in error path when that was allocated
by kmalloc().

Signed-off-by: Chengguang Xu <cgxu519@mykernel.net>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
block/bio-integrity: don't free 'buf' if bio_integrity_add_page() failed 2020-07-01T03:17:00+00:00 yu kuai yukuai3@huawei.com 2020-06-01T12:38:56+00:00 81abe6ad4d99550deeeb4e6a058f213097659929 commit a75ca9303175d36af93c0937dd9b1a6422908b8d upstream. commit e7bf90e5afe3 ("block/bio-integrity: fix a memory leak bug") added a kfree() for 'buf' if bio_integrity_add_page() returns '0'. However, the object will be freed in bio_integrity_free() since 'bio->bi_opf' and 'bio->bi_integrity' were set previousy in bio_integrity_alloc(). Fixes: commit e7bf90e5afe3 ("block/bio-integrity: fix a memory leak bug") Signed-off-by: yu kuai <yukuai3@huawei.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Cc: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit a75ca9303175d36af93c0937dd9b1a6422908b8d upstream.

commit e7bf90e5afe3 ("block/bio-integrity: fix a memory leak bug") added
a kfree() for 'buf' if bio_integrity_add_page() returns '0'. However,
the object will be freed in bio_integrity_free() since 'bio->bi_opf' and
'bio->bi_integrity' were set previousy in bio_integrity_alloc().

Fixes: commit e7bf90e5afe3 ("block/bio-integrity: fix a memory leak bug")
Signed-off-by: yu kuai <yukuai3@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Bob Liu <bob.liu@oracle.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
block, bfq: fix use-after-free in bfq_idle_slice_timer_body 2020-04-17T08:48:42+00:00 Zhiqiang Liu liuzhiqiang26@huawei.com 2020-03-19T11:18:13+00:00 d999063be0cf91bff8e0d6daaea21e1a4f70d336 [ Upstream commit 2f95fa5c955d0a9987ffdc3a095e2f4e62c5f2a9 ] In bfq_idle_slice_timer func, bfqq = bfqd->in_service_queue is not in bfqd-lock critical section. The bfqq, which is not equal to NULL in bfq_idle_slice_timer, may be freed after passing to bfq_idle_slice_timer_body. So we will access the freed memory. In addition, considering the bfqq may be in race, we should firstly check whether bfqq is in service before doing something on it in bfq_idle_slice_timer_body func. If the bfqq in race is not in service, it means the bfqq has been expired through __bfq_bfqq_expire func, and wait_request flags has been cleared in __bfq_bfqd_reset_in_service func. So we do not need to re-clear the wait_request of bfqq which is not in service. KASAN log is given as follows: [13058.354613] ================================================================== [13058.354640] BUG: KASAN: use-after-free in bfq_idle_slice_timer+0xac/0x290 [13058.354644] Read of size 8 at addr ffffa02cf3e63f78 by task fork13/19767 [13058.354646] [13058.354655] CPU: 96 PID: 19767 Comm: fork13 [13058.354661] Call trace: [13058.354667] dump_backtrace+0x0/0x310 [13058.354672] show_stack+0x28/0x38 [13058.354681] dump_stack+0xd8/0x108 [13058.354687] print_address_description+0x68/0x2d0 [13058.354690] kasan_report+0x124/0x2e0 [13058.354697] __asan_load8+0x88/0xb0 [13058.354702] bfq_idle_slice_timer+0xac/0x290 [13058.354707] __hrtimer_run_queues+0x298/0x8b8 [13058.354710] hrtimer_interrupt+0x1b8/0x678 [13058.354716] arch_timer_handler_phys+0x4c/0x78 [13058.354722] handle_percpu_devid_irq+0xf0/0x558 [13058.354731] generic_handle_irq+0x50/0x70 [13058.354735] __handle_domain_irq+0x94/0x110 [13058.354739] gic_handle_irq+0x8c/0x1b0 [13058.354742] el1_irq+0xb8/0x140 [13058.354748] do_wp_page+0x260/0xe28 [13058.354752] __handle_mm_fault+0x8ec/0x9b0 [13058.354756] handle_mm_fault+0x280/0x460 [13058.354762] do_page_fault+0x3ec/0x890 [13058.354765] do_mem_abort+0xc0/0x1b0 [13058.354768] el0_da+0x24/0x28 [13058.354770] [13058.354773] Allocated by task 19731: [13058.354780] kasan_kmalloc+0xe0/0x190 [13058.354784] kasan_slab_alloc+0x14/0x20 [13058.354788] kmem_cache_alloc_node+0x130/0x440 [13058.354793] bfq_get_queue+0x138/0x858 [13058.354797] bfq_get_bfqq_handle_split+0xd4/0x328 [13058.354801] bfq_init_rq+0x1f4/0x1180 [13058.354806] bfq_insert_requests+0x264/0x1c98 [13058.354811] blk_mq_sched_insert_requests+0x1c4/0x488 [13058.354818] blk_mq_flush_plug_list+0x2d4/0x6e0 [13058.354826] blk_flush_plug_list+0x230/0x548 [13058.354830] blk_finish_plug+0x60/0x80 [13058.354838] read_pages+0xec/0x2c0 [13058.354842] __do_page_cache_readahead+0x374/0x438 [13058.354846] ondemand_readahead+0x24c/0x6b0 [13058.354851] page_cache_sync_readahead+0x17c/0x2f8 [13058.354858] generic_file_buffered_read+0x588/0xc58 [13058.354862] generic_file_read_iter+0x1b4/0x278 [13058.354965] ext4_file_read_iter+0xa8/0x1d8 [ext4] [13058.354972] __vfs_read+0x238/0x320 [13058.354976] vfs_read+0xbc/0x1c0 [13058.354980] ksys_read+0xdc/0x1b8 [13058.354984] __arm64_sys_read+0x50/0x60 [13058.354990] el0_svc_common+0xb4/0x1d8 [13058.354994] el0_svc_handler+0x50/0xa8 [13058.354998] el0_svc+0x8/0xc [13058.354999] [13058.355001] Freed by task 19731: [13058.355007] __kasan_slab_free+0x120/0x228 [13058.355010] kasan_slab_free+0x10/0x18 [13058.355014] kmem_cache_free+0x288/0x3f0 [13058.355018] bfq_put_queue+0x134/0x208 [13058.355022] bfq_exit_icq_bfqq+0x164/0x348 [13058.355026] bfq_exit_icq+0x28/0x40 [13058.355030] ioc_exit_icq+0xa0/0x150 [13058.355035] put_io_context_active+0x250/0x438 [13058.355038] exit_io_context+0xd0/0x138 [13058.355045] do_exit+0x734/0xc58 [13058.355050] do_group_exit+0x78/0x220 [13058.355054] __wake_up_parent+0x0/0x50 [13058.355058] el0_svc_common+0xb4/0x1d8 [13058.355062] el0_svc_handler+0x50/0xa8 [13058.355066] el0_svc+0x8/0xc [13058.355067] [13058.355071] The buggy address belongs to the object at ffffa02cf3e63e70#012 which belongs to the cache bfq_queue of size 464 [13058.355075] The buggy address is located 264 bytes inside of#012 464-byte region [ffffa02cf3e63e70, ffffa02cf3e64040) [13058.355077] The buggy address belongs to the page: [13058.355083] page:ffff7e80b3cf9800 count:1 mapcount:0 mapping:ffff802db5c90780 index:0xffffa02cf3e606f0 compound_mapcount: 0 [13058.366175] flags: 0x2ffffe0000008100(slab|head) [13058.370781] raw: 2ffffe0000008100 ffff7e80b53b1408 ffffa02d730c1c90 ffff802db5c90780 [13058.370787] raw: ffffa02cf3e606f0 0000000000370023 00000001ffffffff 0000000000000000 [13058.370789] page dumped because: kasan: bad access detected [13058.370791] [13058.370792] Memory state around the buggy address: [13058.370797] ffffa02cf3e63e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fb fb [13058.370801] ffffa02cf3e63e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [13058.370805] >ffffa02cf3e63f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [13058.370808] ^ [13058.370811] ffffa02cf3e63f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb [13058.370815] ffffa02cf3e64000: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc [13058.370817] ================================================================== [13058.370820] Disabling lock debugging due to kernel taint Here, we directly pass the bfqd to bfq_idle_slice_timer_body func. -- V2->V3: rewrite the comment as suggested by Paolo Valente V1->V2: add one comment, and add Fixes and Reported-by tag. Fixes: aee69d78d ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler") Acked-by: Paolo Valente <paolo.valente@linaro.org> Reported-by: Wang Wang <wangwang2@huawei.com> Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com> Signed-off-by: Feilong Lin <linfeilong@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 2f95fa5c955d0a9987ffdc3a095e2f4e62c5f2a9 ]

In bfq_idle_slice_timer func, bfqq = bfqd->in_service_queue is
not in bfqd-lock critical section. The bfqq, which is not
equal to NULL in bfq_idle_slice_timer, may be freed after passing
to bfq_idle_slice_timer_body. So we will access the freed memory.

In addition, considering the bfqq may be in race, we should
firstly check whether bfqq is in service before doing something
on it in bfq_idle_slice_timer_body func. If the bfqq in race is
not in service, it means the bfqq has been expired through
__bfq_bfqq_expire func, and wait_request flags has been cleared in
__bfq_bfqd_reset_in_service func. So we do not need to re-clear the
wait_request of bfqq which is not in service.

KASAN log is given as follows:
[13058.354613] ==================================================================
[13058.354640] BUG: KASAN: use-after-free in bfq_idle_slice_timer+0xac/0x290
[13058.354644] Read of size 8 at addr ffffa02cf3e63f78 by task fork13/19767
[13058.354646]
[13058.354655] CPU: 96 PID: 19767 Comm: fork13
[13058.354661] Call trace:
[13058.354667]  dump_backtrace+0x0/0x310
[13058.354672]  show_stack+0x28/0x38
[13058.354681]  dump_stack+0xd8/0x108
[13058.354687]  print_address_description+0x68/0x2d0
[13058.354690]  kasan_report+0x124/0x2e0
[13058.354697]  __asan_load8+0x88/0xb0
[13058.354702]  bfq_idle_slice_timer+0xac/0x290
[13058.354707]  __hrtimer_run_queues+0x298/0x8b8
[13058.354710]  hrtimer_interrupt+0x1b8/0x678
[13058.354716]  arch_timer_handler_phys+0x4c/0x78
[13058.354722]  handle_percpu_devid_irq+0xf0/0x558
[13058.354731]  generic_handle_irq+0x50/0x70
[13058.354735]  __handle_domain_irq+0x94/0x110
[13058.354739]  gic_handle_irq+0x8c/0x1b0
[13058.354742]  el1_irq+0xb8/0x140
[13058.354748]  do_wp_page+0x260/0xe28
[13058.354752]  __handle_mm_fault+0x8ec/0x9b0
[13058.354756]  handle_mm_fault+0x280/0x460
[13058.354762]  do_page_fault+0x3ec/0x890
[13058.354765]  do_mem_abort+0xc0/0x1b0
[13058.354768]  el0_da+0x24/0x28
[13058.354770]
[13058.354773] Allocated by task 19731:
[13058.354780]  kasan_kmalloc+0xe0/0x190
[13058.354784]  kasan_slab_alloc+0x14/0x20
[13058.354788]  kmem_cache_alloc_node+0x130/0x440
[13058.354793]  bfq_get_queue+0x138/0x858
[13058.354797]  bfq_get_bfqq_handle_split+0xd4/0x328
[13058.354801]  bfq_init_rq+0x1f4/0x1180
[13058.354806]  bfq_insert_requests+0x264/0x1c98
[13058.354811]  blk_mq_sched_insert_requests+0x1c4/0x488
[13058.354818]  blk_mq_flush_plug_list+0x2d4/0x6e0
[13058.354826]  blk_flush_plug_list+0x230/0x548
[13058.354830]  blk_finish_plug+0x60/0x80
[13058.354838]  read_pages+0xec/0x2c0
[13058.354842]  __do_page_cache_readahead+0x374/0x438
[13058.354846]  ondemand_readahead+0x24c/0x6b0
[13058.354851]  page_cache_sync_readahead+0x17c/0x2f8
[13058.354858]  generic_file_buffered_read+0x588/0xc58
[13058.354862]  generic_file_read_iter+0x1b4/0x278
[13058.354965]  ext4_file_read_iter+0xa8/0x1d8 [ext4]
[13058.354972]  __vfs_read+0x238/0x320
[13058.354976]  vfs_read+0xbc/0x1c0
[13058.354980]  ksys_read+0xdc/0x1b8
[13058.354984]  __arm64_sys_read+0x50/0x60
[13058.354990]  el0_svc_common+0xb4/0x1d8
[13058.354994]  el0_svc_handler+0x50/0xa8
[13058.354998]  el0_svc+0x8/0xc
[13058.354999]
[13058.355001] Freed by task 19731:
[13058.355007]  __kasan_slab_free+0x120/0x228
[13058.355010]  kasan_slab_free+0x10/0x18
[13058.355014]  kmem_cache_free+0x288/0x3f0
[13058.355018]  bfq_put_queue+0x134/0x208
[13058.355022]  bfq_exit_icq_bfqq+0x164/0x348
[13058.355026]  bfq_exit_icq+0x28/0x40
[13058.355030]  ioc_exit_icq+0xa0/0x150
[13058.355035]  put_io_context_active+0x250/0x438
[13058.355038]  exit_io_context+0xd0/0x138
[13058.355045]  do_exit+0x734/0xc58
[13058.355050]  do_group_exit+0x78/0x220
[13058.355054]  __wake_up_parent+0x0/0x50
[13058.355058]  el0_svc_common+0xb4/0x1d8
[13058.355062]  el0_svc_handler+0x50/0xa8
[13058.355066]  el0_svc+0x8/0xc
[13058.355067]
[13058.355071] The buggy address belongs to the object at ffffa02cf3e63e70#012 which belongs to the cache bfq_queue of size 464
[13058.355075] The buggy address is located 264 bytes inside of#012 464-byte region [ffffa02cf3e63e70, ffffa02cf3e64040)
[13058.355077] The buggy address belongs to the page:
[13058.355083] page:ffff7e80b3cf9800 count:1 mapcount:0 mapping:ffff802db5c90780 index:0xffffa02cf3e606f0 compound_mapcount: 0
[13058.366175] flags: 0x2ffffe0000008100(slab|head)
[13058.370781] raw: 2ffffe0000008100 ffff7e80b53b1408 ffffa02d730c1c90 ffff802db5c90780
[13058.370787] raw: ffffa02cf3e606f0 0000000000370023 00000001ffffffff 0000000000000000
[13058.370789] page dumped because: kasan: bad access detected
[13058.370791]
[13058.370792] Memory state around the buggy address:
[13058.370797]  ffffa02cf3e63e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fb fb
[13058.370801]  ffffa02cf3e63e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[13058.370805] >ffffa02cf3e63f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[13058.370808]                                                                 ^
[13058.370811]  ffffa02cf3e63f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[13058.370815]  ffffa02cf3e64000: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
[13058.370817] ==================================================================
[13058.370820] Disabling lock debugging due to kernel taint

Here, we directly pass the bfqd to bfq_idle_slice_timer_body func.
--
V2->V3: rewrite the comment as suggested by Paolo Valente
V1->V2: add one comment, and add Fixes and Reported-by tag.

Fixes: aee69d78d ("block, bfq: introduce the BFQ-v0 I/O scheduler as an extra scheduler")
Acked-by: Paolo Valente <paolo.valente@linaro.org>
Reported-by: Wang Wang <wangwang2@huawei.com>
Signed-off-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: Feilong Lin <linfeilong@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>