Pull block fixes from Jens Axboe:

 - NVMe pull request (Christoph):
    - tracing fix (Keith Busch)
    - fix multipath head refcounting (Hannes Reinecke)
    - Write Zeroes vs PI fix (me)
    - drop a bogus WARN_ON (Zhihao Cheng)

 - Increase max blk-cgroup policy size, now that mq-deadline
   uses it too (Oleksandr)

* tag 'block-5.14-2021-07-24' of git://git.kernel.dk/linux-block:
  nvme: set the PRACT bit when using Write Zeroes with T10 PI
  nvme: fix nvme_setup_command metadata trace event
  nvme: fix refcounting imbalance when all paths are down
  nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING
  block: increase BLKCG_MAX_POLS

Pull i2c fixes from Wolfram Sang:
 "Two bugfixes for the I2C subsystem"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  i2c: mpc: Poll for MCF
  misc: eeprom: at24: Always append device id even if label property is set.

Merge misc mm fixes from Andrew Morton:
 "15 patches.

  VM subsystems affected by this patch series: userfaultfd, kfence,
  highmem, pagealloc, memblock, pagecache, secretmem, pagemap, and
  hugetlbfs"

* akpm:
  hugetlbfs: fix mount mode command line processing
  mm: fix the deadlock in finish_fault()
  mm: mmap_lock: fix disabling preemption directly
  mm/secretmem: wire up ->set_page_dirty
  writeback, cgroup: do not reparent dax inodes
  writeback, cgroup: remove wb from offline list before releasing refcnt
  memblock: make for_each_mem_range() traverse MEMBLOCK_HOTPLUG regions
  mm: page_alloc: fix page_poison=1 / INIT_ON_ALLOC_DEFAULT_ON interaction
  mm: use kmap_local_page in memzero_page
  mm: call flush_dcache_page() in memcpy_to_page() and memzero_page()
  kfence: skip all GFP_ZONEMASK allocations
  kfence: move the size check to the beginning of __kfence_alloc()
  kfence: defer kfence_test_init to ensure that kunit debugfs is created
  selftest: use mmap instead of posix_memalign to allocate memory
  userfaultfd: do not untag user pointers

In commit 32021982 ("hugetlbfs: Convert to fs_context") processing
of the mount mode string was changed from match_octal() to fsparam_u32.

This changed existing behavior as match_octal does not require octal
values to have a '0' prefix, but fsparam_u32 does.

Use fsparam_u32oct which provides the same behavior as match_octal.

Link: https://lkml.kernel.org/r/20210721183326.102716-1-mike.kravetz@oracle.com
Fixes: 32021982 ("hugetlbfs: Convert to fs_context")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: Dennis Camera <bugs+kernel.org@dtnr.ch>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 63f3655f ("mm, memcg: fix reclaim deadlock with writeback")
fix the following ABBA deadlock by pre-allocating the pte page table
without holding the page lock.

	                                lock_page(A)
                                        SetPageWriteback(A)
                                        unlock_page(A)
  lock_page(B)
                                        lock_page(B)
  pte_alloc_one
    shrink_page_list
      wait_on_page_writeback(A)
                                        SetPageWriteback(B)
                                        unlock_page(B)

                                        # flush A, B to clear the writeback

Commit f9ce0be7 ("mm: Cleanup faultaround and finish_fault()
codepaths") reworked the relevant code but ignored this race.  This will
cause the deadlock above to appear again, so fix it.

Link: https://lkml.kernel.org/r/20210721074849.57004-1-zhengqi.arch@bytedance.com
Fixes: f9ce0be7 ("mm: Cleanup faultaround and finish_fault() codepaths")
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 832b5072 ("mm: mmap_lock: use local locks instead of
disabling preemption") fixed a bug by using local locks.

But commit d01079f3 ("mm/mmap_lock: remove dead code for
!CONFIG_TRACING configurations") changed those lines back to the
original version.

I guess it was introduced by fixing conflicts.

Link: https://lkml.kernel.org/r/20210720074228.76342-1-songmuchun@bytedance.com
Fixes: d01079f3 ("mm/mmap_lock: remove dead code for !CONFIG_TRACING configurations")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta@ionos.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Make secretmem up to date with the changes done in commit 0af57378
("mm: require ->set_page_dirty to be explicitly wired up") so that
unconditional call to this method won't cause crashes.

Link: https://lkml.kernel.org/r/20210716063933.31633-1-rppt@kernel.org
Fixes: 0af57378 ("mm: require ->set_page_dirty to be explicitly wired up")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The inode switching code is not suited for dax inodes.  An attempt to
switch a dax inode to a parent writeback structure (as a part of a
writeback cleanup procedure) results in a panic like this:

  run fstests generic/270 at 2021-07-15 05:54:02
  XFS (pmem0p2): EXPERIMENTAL big timestamp feature in use.  Use at your own risk!
  XFS (pmem0p2): DAX enabled. Warning: EXPERIMENTAL, use at your own risk
  XFS (pmem0p2): EXPERIMENTAL inode btree counters feature in use. Use at your own risk!
  XFS (pmem0p2): Mounting V5 Filesystem
  XFS (pmem0p2): Ending clean mount
  XFS (pmem0p2): Quotacheck needed: Please wait.
  XFS (pmem0p2): Quotacheck: Done.
  XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks)
  XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks)
  XFS (pmem0p2): xlog_verify_grant_tail: space > BBTOB(tail_blocks)
  BUG: unable to handle page fault for address: 0000000005b0f669
  #PF: supervisor read access in kernel mode
  #PF: error_code(0x0000) - not-present page
  PGD 0 P4D 0
  Oops: 0000 [#1] SMP PTI
  CPU: 13 PID: 10479 Comm: kworker/13:16 Not tainted 5.14.0-rc1-master-8096acd7+ #8
  Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 09/13/2016
  Workqueue: inode_switch_wbs inode_switch_wbs_work_fn
  RIP: 0010:inode_do_switch_wbs+0xaf/0x470
  Code: 00 30 0f 85 c1 03 00 00 0f 1f 44 00 00 31 d2 48 c7 c6 ff ff ff ff 48 8d 7c 24 08 e8 eb 49 1a 00 48 85 c0 74 4a bb ff ff ff ff <48> 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 00 a8 08 0f 85
  RSP: 0018:ffff9c66691abdc8 EFLAGS: 00010002
  RAX: 0000000005b0f661 RBX: 00000000ffffffff RCX: ffff89e6a21382b0
  RDX: 0000000000000001 RSI: ffff89e350230248 RDI: ffffffffffffffff
  RBP: ffff89e681d19400 R08: 0000000000000000 R09: 0000000000000228
  R10: ffffffffffffffff R11: ffffffffffffffc0 R12: ffff89e6a2138130
  R13: ffff89e316af7400 R14: ffff89e316af6e78 R15: ffff89e6a21382b0
  FS:  0000000000000000(0000) GS:ffff89ee5fb40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000005b0f669 CR3: 0000000cb2410004 CR4: 00000000001706e0
  Call Trace:
   inode_switch_wbs_work_fn+0xb6/0x2a0
   process_one_work+0x1e6/0x380
   worker_thread+0x53/0x3d0
   kthread+0x10f/0x130
   ret_from_fork+0x22/0x30
  Modules linked in: xt_CHECKSUM xt_MASQUERADE xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nft_counter nf_tables nfnetlink bridge stp llc rfkill sunrpc intel_rapl_msr intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel ipmi_ssif kvm mgag200 i2c_algo_bit iTCO_wdt irqbypass drm_kms_helper iTCO_vendor_support acpi_ipmi rapl syscopyarea sysfillrect intel_cstate ipmi_si sysimgblt ioatdma dax_pmem_compat fb_sys_fops ipmi_devintf device_dax i2c_i801 pcspkr intel_uncore hpilo nd_pmem cec dax_pmem_core dca i2c_smbus acpi_tad lpc_ich ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sd_mod t10_pi crct10dif_pclmul crc32_pclmul crc32c_intel tg3 ghash_clmulni_intel serio_raw hpsa hpwdt scsi_transport_sas wmi dm_mirror dm_region_hash dm_log dm_mod
  CR2: 0000000005b0f669
  ---[ end trace ed2105faff8384f3 ]---
  RIP: 0010:inode_do_switch_wbs+0xaf/0x470
  Code: 00 30 0f 85 c1 03 00 00 0f 1f 44 00 00 31 d2 48 c7 c6 ff ff ff ff 48 8d 7c 24 08 e8 eb 49 1a 00 48 85 c0 74 4a bb ff ff ff ff <48> 8b 50 08 48 8d 4a ff 83 e2 01 48 0f 45 c1 48 8b 00 a8 08 0f 85
  RSP: 0018:ffff9c66691abdc8 EFLAGS: 00010002
  RAX: 0000000005b0f661 RBX: 00000000ffffffff RCX: ffff89e6a21382b0
  RDX: 0000000000000001 RSI: ffff89e350230248 RDI: ffffffffffffffff
  RBP: ffff89e681d19400 R08: 0000000000000000 R09: 0000000000000228
  R10: ffffffffffffffff R11: ffffffffffffffc0 R12: ffff89e6a2138130
  R13: ffff89e316af7400 R14: ffff89e316af6e78 R15: ffff89e6a21382b0
  FS:  0000000000000000(0000) GS:ffff89ee5fb40000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000005b0f669 CR3: 0000000cb2410004 CR4: 00000000001706e0
  Kernel panic - not syncing: Fatal exception
  Kernel Offset: 0x15200000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
  ---[ end Kernel panic - not syncing: Fatal exception ]---

The crash happens on an attempt to iterate over attached pagecache pages
and check the dirty flag: a dax inode's xarray contains pfn's instead of
generic struct page pointers.

This happens for DAX and not for other kinds of non-page entries in the
inodes because it's a tagged iteration, and shadow/swap entries are
never tagged; only DAX entries get tagged.

Fix the problem by bailing out (with the false return value) of
inode_prepare_sbs_switch() if a dax inode is passed.

[willy@infradead.org: changelog addition]

Link: https://lkml.kernel.org/r/20210719171350.3876830-1-guro@fb.com
Fixes: c22d70a1 ("writeback, cgroup: release dying cgwbs by switching attached inodes")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Murphy Zhou <jencce.kernel@gmail.com>
Reported-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Darrick J. Wong <djwong@kernel.org>
Tested-by: Murphy Zhou <jencce.kernel@gmail.com>
Acked-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Boyang reported that the commit c22d70a1 ("writeback, cgroup:
release dying cgwbs by switching attached inodes") causes the kernel to
crash while running xfstests generic/256 on ext4 on aarch64 and ppc64le.

  run fstests generic/256 at 2021-07-12 05:41:40
  EXT4-fs (vda3): mounted filesystem with ordered data mode. Opts: . Quota mode: none.
  Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
  Mem abort info:
     ESR = 0x96000005
     EC = 0x25: DABT (current EL), IL = 32 bits
     SET = 0, FnV = 0
     EA = 0, S1PTW = 0
     FSC = 0x05: level 1 translation fault
  Data abort info:
     ISV = 0, ISS = 0x00000005
     CM = 0, WnR = 0
  user pgtable: 64k pages, 48-bit VAs, pgdp=00000000b0502000
  [0000000000000000] pgd=0000000000000000, p4d=0000000000000000, pud=0000000000000000
  Internal error: Oops: 96000005 [#1] SMP
  Modules linked in: dm_flakey dm_snapshot dm_bufio dm_zero dm_mod loop tls rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs rfkill sunrpc ext4 vfat fat mbcache jbd2 drm fuse xfs libcrc32c crct10dif_ce ghash_ce sha2_ce sha256_arm64 sha1_ce virtio_blk virtio_net net_failover virtio_console failover virtio_mmio aes_neon_bs [last unloaded: scsi_debug]
  CPU: 0 PID: 408468 Comm: kworker/u8:5 Tainted: G X --------- ---  5.14.0-0.rc1.15.bx.el9.aarch64 #1
  Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015
  Workqueue: events_unbound cleanup_offline_cgwbs_workfn
  pstate: 004000c5 (nzcv daIF +PAN -UAO -TCO BTYPE=--)
  pc : cleanup_offline_cgwbs_workfn+0x320/0x394
  lr : cleanup_offline_cgwbs_workfn+0xe0/0x394
  sp : ffff80001554fd10
  x29: ffff80001554fd10 x28: 0000000000000000 x27: 0000000000000001
  x26: 0000000000000000 x25: 00000000000000e0 x24: ffffd2a2fbe671a8
  x23: ffff80001554fd88 x22: ffffd2a2fbe67198 x21: ffffd2a2fc25a730
  x20: ffff210412bc3000 x19: ffff210412bc3280 x18: 0000000000000000
  x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
  x14: 0000000000000000 x13: 0000000000000030 x12: 0000000000000040
  x11: ffff210481572238 x10: ffff21048157223a x9 : ffffd2a2fa276c60
  x8 : ffff210484106b60 x7 : 0000000000000000 x6 : 000000000007d18a
  x5 : ffff210416a86400 x4 : ffff210412bc0280 x3 : 0000000000000000
  x2 : ffff80001554fd88 x1 : ffff210412bc0280 x0 : 0000000000000003
  Call trace:
     cleanup_offline_cgwbs_workfn+0x320/0x394
     process_one_work+0x1f4/0x4b0
     worker_thread+0x184/0x540
     kthread+0x114/0x120
     ret_from_fork+0x10/0x18
  Code: d63f0020 97f99963 17ffffa6 f8588263 (f9400061)
  ---[ end trace e250fe289272792a ]---
  Kernel panic - not syncing: Oops: Fatal exception
  SMP: stopping secondary CPUs
  SMP: failed to stop secondary CPUs 0-2
  Kernel Offset: 0x52a2e9fa0000 from 0xffff800010000000
  PHYS_OFFSET: 0xfff0defca0000000
  CPU features: 0x00200251,23200840
  Memory Limit: none
  ---[ end Kernel panic - not syncing: Oops: Fatal exception ]---

The problem happens when cgwb_release_workfn() races with
cleanup_offline_cgwbs_workfn(): wb_tryget() in
cleanup_offline_cgwbs_workfn() can be called after percpu_ref_exit() is
cgwb_release_workfn(), which is basically a use-after-free error.

Fix the problem by making removing the writeback structure from the
offline list before releasing the percpu reference counter.  It will
guarantee that cleanup_offline_cgwbs_workfn() will not see and not
access writeback structures which are about to be released.

Link: https://lkml.kernel.org/r/20210716201039.3762203-1-guro@fb.com
Fixes: c22d70a1 ("writeback, cgroup: release dying cgwbs by switching attached inodes")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reported-by: Boyang Xue <bxue@redhat.com>
Suggested-by: Jan Kara <jack@suse.cz>
Tested-by: Darrick J. Wong <djwong@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Murphy Zhou <jencce.kernel@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit b10d6bca ("arch, drivers: replace for_each_membock() with
for_each_mem_range()") didn't take into account that when there is
movable_node parameter in the kernel command line, for_each_mem_range()
would skip ranges marked with MEMBLOCK_HOTPLUG.

The page table setup code in POWER uses for_each_mem_range() to create
the linear mapping of the physical memory and since the regions marked
as MEMORY_HOTPLUG are skipped, they never make it to the linear map.

A later access to the memory in those ranges will fail:

  BUG: Unable to handle kernel data access on write at 0xc000000400000000
  Faulting instruction address: 0xc00000000008a3c0
  Oops: Kernel access of bad area, sig: 11 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 0 PID: 53 Comm: kworker/u2:0 Not tainted 5.13.0 #7
  NIP:  c00000000008a3c0 LR: c0000000003c1ed8 CTR: 0000000000000040
  REGS: c000000008a57770 TRAP: 0300   Not tainted  (5.13.0)
  MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 84222202  XER: 20040000
  CFAR: c0000000003c1ed4 DAR: c000000400000000 DSISR: 42000000 IRQMASK: 0
  GPR00: c0000000003c1ed8 c000000008a57a10 c0000000019da700 c000000400000000
  GPR04: 0000000000000280 0000000000000180 0000000000000400 0000000000000200
  GPR08: 0000000000000100 0000000000000080 0000000000000040 0000000000000300
  GPR12: 0000000000000380 c000000001bc0000 c0000000001660c8 c000000006337e00
  GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
  GPR20: 0000000040000000 0000000020000000 c000000001a81990 c000000008c30000
  GPR24: c000000008c20000 c000000001a81998 000fffffffff0000 c000000001a819a0
  GPR28: c000000001a81908 c00c000001000000 c000000008c40000 c000000008a64680
  NIP clear_user_page+0x50/0x80
  LR __handle_mm_fault+0xc88/0x1910
  Call Trace:
    __handle_mm_fault+0xc44/0x1910 (unreliable)
    handle_mm_fault+0x130/0x2a0
    __get_user_pages+0x248/0x610
    __get_user_pages_remote+0x12c/0x3e0
    get_arg_page+0x54/0xf0
    copy_string_kernel+0x11c/0x210
    kernel_execve+0x16c/0x220
    call_usermodehelper_exec_async+0x1b0/0x2f0
    ret_from_kernel_thread+0x5c/0x70
  Instruction dump:
  79280fa4 79271764 79261f24 794ae8e2 7ca94214 7d683a14 7c893a14 7d893050
  7d4903a6 60000000 60000000 60000000 <7c001fec> 7c091fec 7c081fec 7c051fec
  ---[ end trace 490b8c67e6075e09 ]---

Making for_each_mem_range() include MEMBLOCK_HOTPLUG regions in the
traversal fixes this issue.

Link: https://bugzilla.redhat.com/show_bug.cgi?id=1976100
Link: https://lkml.kernel.org/r/20210712071132.20902-1-rppt@kernel.org
Fixes: b10d6bca ("arch, drivers: replace for_each_membock() with for_each_mem_range()")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Greg Kurz <groug@kaod.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>	[5.10+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

To reproduce the failure we need the following system:

 - kernel command: page_poison=1 init_on_free=0 init_on_alloc=0

 - kernel config:
    * CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
    * CONFIG_INIT_ON_FREE_DEFAULT_ON=y
    * CONFIG_PAGE_POISONING=y

Resulting in:

    0000000085629bdd: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    0000000022861832: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00000000c597f5b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    CPU: 11 PID: 15195 Comm: bash Kdump: loaded Tainted: G     U     O      5.13.1-gentoo-x86_64 #1
    Hardware name: System manufacturer System Product Name/PRIME Z370-A, BIOS 2801 01/13/2021
    Call Trace:
     dump_stack+0x64/0x7c
     __kernel_unpoison_pages.cold+0x48/0x84
     post_alloc_hook+0x60/0xa0
     get_page_from_freelist+0xdb8/0x1000
     __alloc_pages+0x163/0x2b0
     __get_free_pages+0xc/0x30
     pgd_alloc+0x2e/0x1a0
     mm_init+0x185/0x270
     dup_mm+0x6b/0x4f0
     copy_process+0x190d/0x1b10
     kernel_clone+0xba/0x3b0
     __do_sys_clone+0x8f/0xb0
     do_syscall_64+0x68/0x80
     entry_SYSCALL_64_after_hwframe+0x44/0xae

Before commit 51cba1eb ("init_on_alloc: Optimize static branches")
init_on_alloc never enabled static branch by default.  It could only be
enabed explicitly by init_mem_debugging_and_hardening().

But after commit 51cba1eb, a static branch could already be enabled
by default.  There was no code to ever disable it.  That caused
page_poison=1 / init_on_free=1 conflict.

This change extends init_mem_debugging_and_hardening() to also disable
static branch disabling.

Link: https://lkml.kernel.org/r/20210714031935.4094114-1-keescook@chromium.org
Link: https://lore.kernel.org/r/20210712215816.1512739-1-slyfox@gentoo.org
Fixes: 51cba1eb ("init_on_alloc: Optimize static branches")
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Kees Cook <keescook@chromium.org>
Reported-by: Mikhail Morfikov <mmorfikov@gmail.com>
Reported-by: <bowsingbetee@pm.me>
Tested-by: <bowsingbetee@protonmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The commit message introducing the global memzero_page explicitly
mentions switching to kmap_local_page in the commit log but doesn't
actually do that.

Link: https://lkml.kernel.org/r/20210713055231.137602-3-hch@lst.de
Fixes: 28961998 ("iov_iter: lift memzero_page() to highmem.h")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memcpy_to_page and memzero_page can write to arbitrary pages, which
could be in the page cache or in high memory, so call
flush_kernel_dcache_pages to flush the dcache.

This is a problem when using these helpers on dcache challeneged
architectures.  Right now there are just a few users, chances are no one
used the PC floppy driver, the aha1542 driver for an ISA SCSI HBA, and a
few advanced and optional btrfs and ext4 features on those platforms yet
since the conversion.

Link: https://lkml.kernel.org/r/20210713055231.137602-2-hch@lst.de
Fixes: bb90d4bc ("mm/highmem: Lift memcpy_[to|from]_page to core")
Fixes: 28961998 ("iov_iter: lift memzero_page() to highmem.h")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Allocation requests outside ZONE_NORMAL (MOVABLE, HIGHMEM or DMA) cannot
be fulfilled by KFENCE, because KFENCE memory pool is located in a zone
different from the requested one.

Because callers of kmem_cache_alloc() may actually rely on the
allocation to reside in the requested zone (e.g.  memory allocations
done with __GFP_DMA must be DMAable), skip all allocations done with
GFP_ZONEMASK and/or respective SLAB flags (SLAB_CACHE_DMA and
SLAB_CACHE_DMA32).

Link: https://lkml.kernel.org/r/20210714092222.1890268-2-glider@google.com
Fixes: 0ce20dd8 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Acked-by: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: <stable@vger.kernel.org>	[5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Check the allocation size before toggling kfence_allocation_gate.

This way allocations that can't be served by KFENCE will not result in
waiting for another CONFIG_KFENCE_SAMPLE_INTERVAL without allocating
anything.

Link: https://lkml.kernel.org/r/20210714092222.1890268-1-glider@google.comSigned-off-by: Alexander Potapenko <glider@google.com>
Suggested-by: Marco Elver <elver@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>	[5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kfence_test_init and kunit_init both use the same level late_initcall,
which means if kfence_test_init linked ahead of kunit_init,
kfence_test_init will get a NULL debugfs_rootdir as parent dentry, then
kfence_test_init and kfence_debugfs_init both create a debugfs node
named "kfence" under debugfs_mount->mnt_root, and it will throw out
"debugfs: Directory 'kfence' with parent '/' already present!" with
EEXIST.  So kfence_test_init should be deferred.

Link: https://lkml.kernel.org/r/20210714113140.2949995-1-o451686892@gmail.comSigned-off-by: Weizhao Ouyang <o451686892@gmail.com>
Tested-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This test passes pointers obtained from anon_allocate_area to the
userfaultfd and mremap APIs.  This causes a problem if the system
allocator returns tagged pointers because with the tagged address ABI
the kernel rejects tagged addresses passed to these APIs, which would
end up causing the test to fail.  To make this test compatible with such
system allocators, stop using the system allocator to allocate memory in
anon_allocate_area, and instead just use mmap.

Link: https://lkml.kernel.org/r/20210714195437.118982-3-pcc@google.com
Link: https://linux-review.googlesource.com/id/Icac91064fcd923f77a83e8e133f8631c5b8fc241
Fixes: c47174fc ("userfaultfd: selftest")
Co-developed-by: Lokesh Gidra <lokeshgidra@google.com>
Signed-off-by: Lokesh Gidra <lokeshgidra@google.com>
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Alistair Delva <adelva@google.com>
Cc: William McVicker <willmcvicker@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Mitch Phillips <mitchp@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: <stable@vger.kernel.org>	[5.4]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "userfaultfd: do not untag user pointers", v5.

If a user program uses userfaultfd on ranges of heap memory, it may end
up passing a tagged pointer to the kernel in the range.start field of
the UFFDIO_REGISTER ioctl.  This can happen when using an MTE-capable
allocator, or on Android if using the Tagged Pointers feature for MTE
readiness [1].

When a fault subsequently occurs, the tag is stripped from the fault
address returned to the application in the fault.address field of struct
uffd_msg.  However, from the application's perspective, the tagged
address *is* the memory address, so if the application is unaware of
memory tags, it may get confused by receiving an address that is, from
its point of view, outside of the bounds of the allocation.  We observed
this behavior in the kselftest for userfaultfd [2] but other
applications could have the same problem.

Address this by not untagging pointers passed to the userfaultfd ioctls.
Instead, let the system call fail.  Also change the kselftest to use
mmap so that it doesn't encounter this problem.

[1] https://source.android.com/devices/tech/debug/tagged-pointers
[2] tools/testing/selftests/vm/userfaultfd.c

This patch (of 2):

Do not untag pointers passed to the userfaultfd ioctls.  Instead, let
the system call fail.  This will provide an early indication of problems
with tag-unaware userspace code instead of letting the code get confused
later, and is consistent with how we decided to handle brk/mmap/mremap
in commit dcde2373 ("mm: Avoid creating virtual address aliases in
brk()/mmap()/mremap()"), as well as being consistent with the existing
tagged address ABI documentation relating to how ioctl arguments are
handled.

The code change is a revert of commit 7d032574 ("userfaultfd: untag
user pointers") plus some fixups to some additional calls to
validate_range that have appeared since then.

[1] https://source.android.com/devices/tech/debug/tagged-pointers
[2] tools/testing/selftests/vm/userfaultfd.c

Link: https://lkml.kernel.org/r/20210714195437.118982-1-pcc@google.com
Link: https://lkml.kernel.org/r/20210714195437.118982-2-pcc@google.com
Link: https://linux-review.googlesource.com/id/I761aa9f0344454c482b83fcfcce547db0a25501b
Fixes: 63f0c603 ("arm64: Introduce prctl() options to control the tagged user addresses ABI")
Signed-off-by: Peter Collingbourne <pcc@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Alistair Delva <adelva@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Lokesh Gidra <lokeshgidra@google.com>
Cc: Mitch Phillips <mitchp@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: William McVicker <willmcvicker@google.com>
Cc: <stable@vger.kernel.org>	[5.4]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull btrfs fixes from David Sterba:
 "A few fixes and one patch to help some block layer API cleanups:

   - skip missing device when running fstrim

   - fix unpersisted i_size on fsync after expanding truncate

   - fix lock inversion problem when doing qgroup extent tracing

   - replace bdgrab/bdput usage, replace gendisk by block_device"

* tag 'for-5.14-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: store a block_device in struct btrfs_ordered_extent
  btrfs: fix lock inversion problem when doing qgroup extent tracing
  btrfs: check for missing device in btrfs_trim_fs
  btrfs: fix unpersisted i_size on fsync after expanding truncate

Pull ceph fixes from Ilya Dryomov:
 "A subtle deadlock on lock_rwsem (marked for stable) and rbd fixes for
  a -rc1 regression.

  Also included a rare WARN condition tweak"

* tag 'ceph-for-5.14-rc3' of git://github.com/ceph/ceph-client:
  rbd: resurrect setting of disk->private_data in rbd_init_disk()
  ceph: don't WARN if we're still opening a session to an MDS
  rbd: don't hold lock_rwsem while running_list is being drained
  rbd: always kick acquire on "acquired" and "released" notifications

Pull tracing fixes from Steven Rostedt:

 - Fix deadloop in ring buffer because of using stale "read" variable

 - Fix synthetic event use of field_pos as boolean and not an index

 - Fixed histogram special var "cpu" overriding event fields called
   "cpu"

 - Cleaned up error prone logic in alloc_synth_event()

 - Removed call to synchronize_rcu_tasks_rude() when not needed

 - Removed redundant initialization of a local variable "ret"

 - Fixed kernel crash when updating tracepoint callbacks of different
   priorities.

* tag 'trace-v5.14-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracepoints: Update static_call before tp_funcs when adding a tracepoint
  ftrace: Remove redundant initialization of variable ret
  ftrace: Avoid synchronize_rcu_tasks_rude() call when not necessary
  tracing: Clean up alloc_synth_event()
  tracing/histogram: Rename "cpu" to "common_cpu"
  tracing: Synthetic event field_pos is an index not a boolean
  tracing: Fix bug in rb_per_cpu_empty() that might cause deadloop.

Pull m68k fix from Geert Uytterhoeven:

 - Fix a Mac defconfig regression due to the IDE -> ATA switch

* tag 'm68k-for-v5.14-tag2' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: MAC should select HAVE_PATA_PLATFORM

Pull ACPI fixes from Rafael Wysocki:
 "These fix a recently broken Kconfig dependency and ACPI device
  reference counting in an iterator macro.

  Specifics:

   - Fix recently broken Kconfig dependency for the ACPI table override
     via built-in initrd (Robert Richter)

   - Fix ACPI device reference counting in the for_each_acpi_dev_match()
     helper macro to avoid use-after-free (Andy Shevchenko)"

* tag 'acpi-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: utils: Fix reference counting in for_each_acpi_dev_match()
  ACPI: Kconfig: Fix table override from built-in initrd

Merge tag 'driver-core-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

Pull driver core fixes from Greg KH:
 "Here are two small driver core fixes to resolve some reported problems
  for 5.14-rc3. They include:

   - aux bus memory leak fix

   - unneeded warning message removed when removing a device link.

  Both have been in linux-next with no reported problems"

* tag 'driver-core-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  driver core: Prevent warning when removing a device link from unregistered consumer
  driver core: auxiliary bus: Fix memory leak when driver_register() fail

Pull char/misc fixes from Greg KH:
 "Here are some small char/misc driver fixes for 5.14-rc3.

  Included in here are:

   - MAINTAINERS file updates for two changes in different driver
     subsystems

   - mhi bus bugfixes

   - nds32 bugfix that resolves a reported problem

  All have been in linux-next with no reported problems"

* tag 'char-misc-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  nds32: fix up stack guard gap
  MAINTAINERS: Change ACRN HSM driver maintainer
  MAINTAINERS: Update for VMCI driver
  bus: mhi: pci_generic: Fix inbound IPCR channel
  bus: mhi: core: Validate channel ID when processing command completions
  bus: mhi: pci_generic: Apply no-op for wake using sideband wake boolean

Pull USB fixes from Greg KH:
 "Here are some USB fixes for 5.14-rc3 to resolve a bunch of tiny
  problems reported. Included in here are:

   - dtsi revert to resolve a problem which broke android systems that
     relied on the dts name to find the USB controller device.

     People are still working out the "real" solution for this, but for
     now the revert is needed.

   - core USB fix for pipe calculation found by syzbot

   - typec fixes

   - gadget driver fixes

   - new usb-serial device ids

   - new USB quirks

   - xhci fixes

   - usb hub fixes for power management issues reported

   - other tiny fixes

  All have been in linux-next with no reported problems"

* tag 'usb-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (27 commits)
  USB: serial: cp210x: add ID for CEL EM3588 USB ZigBee stick
  Revert "USB: quirks: ignore remote wake-up on Fibocom L850-GL LTE modem"
  usb: cdc-wdm: fix build error when CONFIG_WWAN_CORE is not set
  Revert "arm64: dts: qcom: Harmonize DWC USB3 DT nodes name"
  usb: dwc2: gadget: Fix sending zero length packet in DDMA mode.
  usb: dwc2: Skip clock gating on Samsung SoCs
  usb: renesas_usbhs: Fix superfluous irqs happen after usb_pkt_pop()
  usb: dwc2: gadget: Fix GOUTNAK flow for Slave mode.
  usb: phy: Fix page fault from usb_phy_uevent
  usb: xhci: avoid renesas_usb_fw.mem when it's unusable
  usb: gadget: u_serial: remove WARN_ON on null port
  usb: dwc3: avoid NULL access of usb_gadget_driver
  usb: max-3421: Prevent corruption of freed memory
  usb: gadget: Fix Unbalanced pm_runtime_enable in tegra_xudc_probe
  MAINTAINERS: repair reference in USB IP DRIVER FOR HISILICON KIRIN 970
  usb: typec: stusb160x: Don't block probing of consumer of "connector" nodes
  usb: typec: stusb160x: register role switch before interrupt registration
  USB: usb-storage: Add LaCie Rugged USB3-FW to IGNORE_UAS
  usb: ehci: Prevent missed ehci interrupts with edge-triggered MSI
  usb: hub: Disable USB 3 device initiated lpm if exit latency is too high
  ...

Pull sound fixes from Takashi Iwai:
 "A collection of small fixes, mostly covering device-specific
  regressions and bugs over ASoC, HD-audio and USB-audio, while
  the ALSA PCM core received a few additional fixes for the
  possible (new and old) regressions"

* tag 'sound-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (29 commits)
  ALSA: usb-audio: Add registration quirk for JBL Quantum headsets
  ALSA: hda/hdmi: Add quirk to force pin connectivity on NUC10
  ALSA: pcm: Fix mmap without buffer preallocation
  ALSA: pcm: Fix mmap capability check
  ALSA: hda: intel-dsp-cfg: add missing ElkhartLake PCI ID
  ASoC: ti: j721e-evm: Check for not initialized parent_clk_id
  ASoC: ti: j721e-evm: Fix unbalanced domain activity tracking during startup
  ALSA: hda/realtek: Fix pop noise and 2 Front Mic issues on a machine
  ALSA: hdmi: Expose all pins on MSI MS-7C94 board
  ALSA: sb: Fix potential ABBA deadlock in CSP driver
  ASoC: rt5682: Fix the issue of garbled recording after powerd_dbus_suspend
  ASoC: amd: reverse stop sequence for stoneyridge platform
  ASoC: soc-pcm: add a flag to reverse the stop sequence
  ASoC: codecs: wcd938x: setup irq during component bind
  ASoC: dt-bindings: renesas: rsnd: Fix incorrect 'port' regex schema
  ALSA: usb-audio: Add missing proc text entry for BESPOKEN type
  ASoC: codecs: wcd938x: make sdw dependency explicit in Kconfig
  ASoC: SOF: Intel: Update ADL descriptor to use ACPI power states
  ASoC: rt5631: Fix regcache sync errors on resume
  ALSA: pcm: Call substream ack() method upon compat mmap commit
  ...

* acpi-utils:
  ACPI: utils: Fix reference counting in for_each_acpi_dev_match()

Because of the significant overhead that retpolines pose on indirect
calls, the tracepoint code was updated to use the new "static_calls" that
can modify the running code to directly call a function instead of using
an indirect caller, and this function can be changed at runtime.

In the tracepoint code that calls all the registered callbacks that are
attached to a tracepoint, the following is done:

	it_func_ptr = rcu_dereference_raw((&__tracepoint_##name)->funcs);
	if (it_func_ptr) {
		__data = (it_func_ptr)->data;
		static_call(tp_func_##name)(__data, args);
	}

If there's just a single callback, the static_call is updated to just call
that callback directly. Once another handler is added, then the static
caller is updated to call the iterator, that simply loops over all the
funcs in the array and calls each of the callbacks like the old method
using indirect calling.

The issue was discovered with a race between updating the funcs array and
updating the static_call. The funcs array was updated first and then the
static_call was updated. This is not an issue as long as the first element
in the old array is the same as the first element in the new array. But
that assumption is incorrect, because callbacks also have a priority
field, and if there's a callback added that has a higher priority than the
callback on the old array, then it will become the first callback in the
new array. This means that it is possible to call the old callback with
the new callback data element, which can cause a kernel panic.

	static_call = callback1()
	funcs[] = {callback1,data1};
	callback2 has higher priority than callback1

	CPU 1				CPU 2
	-----				-----

   new_funcs = {callback2,data2},
               {callback1,data1}

   rcu_assign_pointer(tp->funcs, new_funcs);

  /*
   * Now tp->funcs has the new array
   * but the static_call still calls callback1
   */

				it_func_ptr = tp->funcs [ new_funcs ]
				data = it_func_ptr->data [ data2 ]
				static_call(callback1, data);

				/* Now callback1 is called with
				 * callback2's data */

				[ KERNEL PANIC ]

   update_static_call(iterator);

To prevent this from happening, always switch the static_call to the
iterator before assigning the tp->funcs to the new array. The iterator will
always properly match the callback with its data.

To trigger this bug:

  In one terminal:

    while :; do hackbench 50; done

  In another terminal

    echo 1 > /sys/kernel/tracing/events/sched/sched_waking/enable
    while :; do
        echo 1 > /sys/kernel/tracing/set_event_pid;
        sleep 0.5
        echo 0 > /sys/kernel/tracing/set_event_pid;
        sleep 0.5
   done

And it doesn't take long to crash. This is because the set_event_pid adds
a callback to the sched_waking tracepoint with a high priority, which will
be called before the sched_waking trace event callback is called.

Note, the removal to a single callback updates the array first, before
changing the static_call to single callback, which is the proper order as
the first element in the array is the same as what the static_call is
being changed to.

Link: https://lore.kernel.org/io-uring/4ebea8f0-58c9-e571-fd30-0ce4f6f09c70@samba.org/

Cc: stable@vger.kernel.org
Fixes: d25e37d8 ("tracepoint: Optimize using static_call()")
Reported-by: Stefan Metzmacher <metze@samba.org>
tested-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

The variable ret is being initialized with a value that is never
read, it is being updated later on. The assignment is redundant and
can be removed.

Link: https://lkml.kernel.org/r/20210721120915.122278-1-colin.king@canonical.com

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

synchronize_rcu_tasks_rude() triggers IPIs and forces rescheduling on
all CPUs. It is a costly operation and, when targeting nohz_full CPUs,
very disrupting (hence the name). So avoid calling it when 'old_hash'
doesn't need to be freed.

Link: https://lkml.kernel.org/r/20210721114726.1545103-1-nsaenzju@redhat.comSigned-off-by: Nicolas Saenz Julienne <nsaenzju@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

alloc_synth_event() currently has the following code to initialize the
event fields and dynamic_fields:

	for (i = 0, j = 0; i < n_fields; i++) {
		event->fields[i] = fields[i];

		if (fields[i]->is_dynamic) {
			event->dynamic_fields[j] = fields[i];
			event->dynamic_fields[j]->field_pos = i;
			event->dynamic_fields[j++] = fields[i];
			event->n_dynamic_fields++;
		}
	}

1) It would make more sense to have all fields keep track of their
   field_pos.

2) event->dynmaic_fields[j] is assigned twice for no reason.

3) We can move updating event->n_dynamic_fields outside the loop, and just
   assign it to j.

This combination makes the code much cleaner.

Link: https://lkml.kernel.org/r/20210721195341.29bb0f77@oasis.local.homeSigned-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Currently the histogram logic allows the user to write "cpu" in as an
event field, and it will record the CPU that the event happened on.

The problem with this is that there's a lot of events that have "cpu"
as a real field, and using "cpu" as the CPU it ran on, makes it
impossible to run histograms on the "cpu" field of events.

For example, if I want to have a histogram on the count of the
workqueue_queue_work event on its cpu field, running:

 ># echo 'hist:keys=cpu' > events/workqueue/workqueue_queue_work/trigger

Gives a misleading and wrong result.

Change the command to "common_cpu" as no event should have "common_*"
fields as that's a reserved name for fields used by all events. And
this makes sense here as common_cpu would be a field used by all events.

Now we can even do:

 ># echo 'hist:keys=common_cpu,cpu if cpu < 100' > events/workqueue/workqueue_queue_work/trigger
 ># cat events/workqueue/workqueue_queue_work/hist
 # event histogram
 #
 # trigger info: hist:keys=common_cpu,cpu:vals=hitcount:sort=hitcount:size=2048 if cpu < 100 [active]
 #

 { common_cpu:          0, cpu:          2 } hitcount:          1
 { common_cpu:          0, cpu:          4 } hitcount:          1
 { common_cpu:          7, cpu:          7 } hitcount:          1
 { common_cpu:          0, cpu:          7 } hitcount:          1
 { common_cpu:          0, cpu:          1 } hitcount:          1
 { common_cpu:          0, cpu:          6 } hitcount:          2
 { common_cpu:          0, cpu:          5 } hitcount:          2
 { common_cpu:          1, cpu:          1 } hitcount:          4
 { common_cpu:          6, cpu:          6 } hitcount:          4
 { common_cpu:          5, cpu:          5 } hitcount:         14
 { common_cpu:          4, cpu:          4 } hitcount:         26
 { common_cpu:          0, cpu:          0 } hitcount:         39
 { common_cpu:          2, cpu:          2 } hitcount:        184

Now for backward compatibility, I added a trick. If "cpu" is used, and
the field is not found, it will fall back to "common_cpu" and work as
it did before. This way, it will still work for old programs that use
"cpu" to get the actual CPU, but if the event has a "cpu" as a field, it
will get that event's "cpu" field, which is probably what it wants
anyway.

I updated the tracefs/README to include documentation about both the
common_timestamp and the common_cpu. This way, if that text is present in
the README, then an application can know that common_cpu is supported over
just plain "cpu".

Link: https://lkml.kernel.org/r/20210721110053.26b4f641@oasis.local.home

Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 8b7622bf ("tracing: Add cpu field for hist triggers")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Performing the following:

 ># echo 'wakeup_lat s32 pid; u64 delta; char wake_comm[]' > synthetic_events
 ># echo 'hist:keys=pid:__arg__1=common_timestamp.usecs' > events/sched/sched_waking/trigger
 ># echo 'hist:keys=next_pid:pid=next_pid,delta=common_timestamp.usecs-$__arg__1:onmatch(sched.sched_waking).trace(wakeup_lat,$pid,$delta,prev_comm)'\
      > events/sched/sched_switch/trigger
 ># echo 1 > events/synthetic/enable

Crashed the kernel:

 BUG: kernel NULL pointer dereference, address: 000000000000001b
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 PGD 0 P4D 0
 Oops: 0000 [#1] PREEMPT SMP
 CPU: 7 PID: 0 Comm: swapper/7 Not tainted 5.13.0-rc5-test+ #104
 Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v03.03 07/14/2016
 RIP: 0010:strlen+0x0/0x20
 Code: f6 82 80 2b 0b bc 20 74 11 0f b6 50 01 48 83 c0 01 f6 82 80 2b 0b bc
  20 75 ef c3 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 <80> 3f 00 74 10
  48 89 f8 48 83 c0 01 80 38 9 f8 c3 31
 RSP: 0018:ffffaa75000d79d0 EFLAGS: 00010046
 RAX: 0000000000000002 RBX: ffff9cdb55575270 RCX: 0000000000000000
 RDX: ffff9cdb58c7a320 RSI: ffffaa75000d7b40 RDI: 000000000000001b
 RBP: ffffaa75000d7b40 R08: ffff9cdb40a4f010 R09: ffffaa75000d7ab8
 R10: ffff9cdb4398c700 R11: 0000000000000008 R12: ffff9cdb58c7a320
 R13: ffff9cdb55575270 R14: ffff9cdb58c7a000 R15: 0000000000000018
 FS:  0000000000000000(0000) GS:ffff9cdb5aa00000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: 000000000000001b CR3: 00000000c0612006 CR4: 00000000001706e0
 Call Trace:
  trace_event_raw_event_synth+0x90/0x1d0
  action_trace+0x5b/0x70
  event_hist_trigger+0x4bd/0x4e0
  ? cpumask_next_and+0x20/0x30
  ? update_sd_lb_stats.constprop.0+0xf6/0x840
  ? __lock_acquire.constprop.0+0x125/0x550
  ? find_held_lock+0x32/0x90
  ? sched_clock_cpu+0xe/0xd0
  ? lock_release+0x155/0x440
  ? update_load_avg+0x8c/0x6f0
  ? enqueue_entity+0x18a/0x920
  ? __rb_reserve_next+0xe5/0x460
  ? ring_buffer_lock_reserve+0x12a/0x3f0
  event_triggers_call+0x52/0xe0
  trace_event_buffer_commit+0x1ae/0x240
  trace_event_raw_event_sched_switch+0x114/0x170
  __traceiter_sched_switch+0x39/0x50
  __schedule+0x431/0xb00
  schedule_idle+0x28/0x40
  do_idle+0x198/0x2e0
  cpu_startup_entry+0x19/0x20
  secondary_startup_64_no_verify+0xc2/0xcb

The reason is that the dynamic events array keeps track of the field
position of the fields array, via the field_pos variable in the
synth_field structure. Unfortunately, that field is a boolean for some
reason, which means any field_pos greater than 1 will be a bug (in this
case it was 2).

Link: https://lkml.kernel.org/r/20210721191008.638bce34@oasis.local.home

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: bd82631d ("tracing: Add support for dynamic strings to synthetic events")
Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull drm fixes from Dave Airlie:
 "Regular fixes - a bunch of amdgpu fixes are the main thing mostly for
  the new gpus. There is also some i915 reverts for older changes that
  were having some unwanted side effects. One nouveau fix for a report
  regressions, and otherwise just some misc fixes.

  core:
   - fix for non-drm ioctls on drm fd

  panel:
   - avoid double free

  ttm:
   - refcounting fix
   - NULL checks

  amdgpu:
   - Yellow Carp updates
   - Add some Yellow Carp DIDs
   - Beige Goby updates
   - CIK 10bit 4K regression fix
   - GFX10 golden settings updates
   - eDP panel regression fix
   - Misc display fixes
   - Aldebaran fix
   - fix COW checks

  nouveau:
   - init BO GEM fields

  i915:
   - revert async command parsing
   - revert fence error propogation
   - GVT fix for shadow ppgtt

  vc4:
   - fix interrupt handling"

* tag 'drm-fixes-2021-07-23' of git://anongit.freedesktop.org/drm/drm: (34 commits)
  drm/panel: raspberrypi-touchscreen: Prevent double-free
  drm/amdgpu - Corrected the video codecs array name for yellow carp
  drm/amd/display: Fix ASSR regression on embedded panels
  drm/amdgpu: add yellow carp pci id (v2)
  drm/amdgpu: update yellow carp external rev_id handling
  drm/amd/pm: Support board calibration on aldebaran
  drm/amd/display: change zstate allow msg condition
  drm/amd/display: Populate dtbclk entries for dcn3.02/3.03
  drm/amd/display: Line Buffer changes
  drm/amd/display: Remove MALL function from DCN3.1
  drm/amd/display: Only set default brightness for OLED
  drm/amd/display: Update bounding box for DCN3.1
  drm/amd/display: Query VCO frequency from register for DCN3.1
  drm/amd/display: Populate socclk entries for dcn3.02/3.03
  drm/amd/display: Fix max vstartup calculation for modes with borders
  drm/amd/display: implement workaround for riommu related hang
  drm/amd/display: Fix comparison error in dcn21 DML
  drm/i915: Correct the docs for intel_engine_cmd_parser
  drm/ttm: add missing NULL checks
  drm/ttm: Force re-init if ttm_global_init() fails
  ...

Merge tag 'fallthrough-fixes-clang-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull fallthrough fix from Gustavo Silva:
 "Fix a fall-through warning when building with -Wimplicit-fallthrough
  on PowerPC"

* tag 'fallthrough-fixes-clang-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  powerpc/pasemi: Fix fall-through warning for Clang

Short summary of fixes pull:

 * Return -ENOTTY for non-DRM ioctls
 * amdgpu: Fix COW checks
 * nouveau: init BO GME fields
 * panel: Avoid double free
 * ttm: Fix refcounting in ttm_global_init(); NULL checks
 * vc4: Fix interrupt handling
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YPlbkmH6S4VAHP9j@linux-uq9g.fritz.box

Merge tag 'drm-intel-fixes-2021-07-22' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

Couple reverts from Jason getting rid of asynchronous command parsing
and fence error propagation and a GVT fix of shadow ppgtt invalidation
with proper D3 state tracking from Colin.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/YPl1sIyruD0U5Orl@intel.com

Merge tag 'array-bounds-fixes-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux

Pull array bounds warning fix from Gustavo Silva:
 "Fix a couple of out-of-bounds warnings in the media subsystem.

  This is part of the ongoing efforts to globally enable -Warray-bounds"

* tag 'array-bounds-fixes-5.14-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux:
  media: ngene: Fix out-of-bounds bug in ngene_command_config_free_buf()

Pull NVMe fixes from Christoph:

"nvme fixes for Linux 5.14:

 - tracing fix (Keith Busch)
 - fix multipath head refcounting (Hannes Reinecke)
 - Write Zeroes vs PI fix (me)
 - drop a bogus WARN_ON (Zhihao Cheng)"

* tag 'nvme-5.14-2021-07-22' of git://git.infradead.org/nvme:
  nvme: set the PRACT bit when using Write Zeroes with T10 PI
  nvme: fix nvme_setup_command metadata trace event
  nvme: fix refcounting imbalance when all paths are down
  nvme-pci: don't WARN_ON in nvme_reset_work if ctrl.state is not RESETTING