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  1. 31 Jul, 2019 20 commits
  3. 28 Jul, 2019 20 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.19.62 · 64f46940
      Greg Kroah-Hartman authored
      64f46940
    • Vlad Buslov's avatar
      net: sched: verify that q!=NULL before setting q->flags · 60e9babf
      Vlad Buslov authored 
      commit 503d81d4 upstream.

In function int tc_new_tfilter() q pointer can be NULL when adding filter
on a shared block. With recent change that resets TCQ_F_CAN_BYPASS after
filter creation, following NULL pointer dereference happens in case parent
block is shared:

[  212.925060] BUG: kernel NULL pointer dereference, address: 0000000000000010
[  212.925445] #PF: supervisor write access in kernel mode
[  212.925709] #PF: error_code(0x0002) - not-present page
[  212.925965] PGD 8000000827923067 P4D 8000000827923067 PUD 827924067 PMD 0
[  212.926302] Oops: 0002 [#1] SMP KASAN PTI
[  212.926539] CPU: 18 PID: 2617 Comm: tc Tainted: G    B             5.2.0+ #512
[  212.926938] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b 03/30/2017
[  212.927364] RIP: 0010:tc_new_tfilter+0x698/0xd40
[  212.927633] Code: 74 0d 48 85 c0 74 08 48 89 ef e8 03 aa 62 00 48 8b 84 24 a0 00 00 00 48 8d 78 10 48 89 44 24 18 e8 4d 0c 6b ff 48 8b 44 24 18 <83> 60 10 f
b 48 85 ed 0f 85 3d fe ff ff e9 4f fe ff ff e8 81 26 f8
[  212.928607] RSP: 0018:ffff88884fd5f5d8 EFLAGS: 00010296
[  212.928905] RAX: 0000000000000000 RBX: 0000000000000000 RCX: dffffc0000000000
[  212.929201] RDX: 0000000000000007 RSI: 0000000000000004 RDI: 0000000000000297
[  212.929402] RBP: ffff88886bedd600 R08: ffffffffb91d4b51 R09: fffffbfff7616e4d
[  212.929609] R10: fffffbfff7616e4c R11: ffffffffbb0b7263 R12: ffff88886bc61040
[  212.929803] R13: ffff88884fd5f950 R14: ffffc900039c5000 R15: ffff88835e927680
[  212.929999] FS:  00007fe7c50b6480(0000) GS:ffff88886f980000(0000) knlGS:0000000000000000
[  212.930235] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  212.930394] CR2: 0000000000000010 CR3: 000000085bd04002 CR4: 00000000001606e0
[  212.930588] Call Trace:
[  212.930682]  ? tc_del_tfilter+0xa40/0xa40
[  212.930811]  ? __lock_acquire+0x5b5/0x2460
[  212.930948]  ? find_held_lock+0x85/0xa0
[  212.931081]  ? tc_del_tfilter+0xa40/0xa40
[  212.931201]  rtnetlink_rcv_msg+0x4ab/0x5f0
[  212.931332]  ? rtnl_dellink+0x490/0x490
[  212.931454]  ? lockdep_hardirqs_on+0x260/0x260
[  212.931589]  ? netlink_deliver_tap+0xab/0x5a0
[  212.931717]  ? match_held_lock+0x1b/0x240
[  212.931844]  netlink_rcv_skb+0xd0/0x200
[  212.931958]  ? rtnl_dellink+0x490/0x490
[  212.932079]  ? netlink_ack+0x440/0x440
[  212.932205]  ? netlink_deliver_tap+0x161/0x5a0
[  212.932335]  ? lock_downgrade+0x360/0x360
[  212.932457]  ? lock_acquire+0xe5/0x210
[  212.932579]  netlink_unicast+0x296/0x350
[  212.932705]  ? netlink_attachskb+0x390/0x390
[  212.932834]  ? _copy_from_iter_full+0xe0/0x3a0
[  212.932976]  netlink_sendmsg+0x394/0x600
[  212.937998]  ? netlink_unicast+0x350/0x350
[  212.943033]  ? move_addr_to_kernel.part.0+0x90/0x90
[  212.948115]  ? netlink_unicast+0x350/0x350
[  212.953185]  sock_sendmsg+0x96/0xa0
[  212.958099]  ___sys_sendmsg+0x482/0x520
[  212.962881]  ? match_held_lock+0x1b/0x240
[  212.967618]  ? copy_msghdr_from_user+0x250/0x250
[  212.972337]  ? lock_downgrade+0x360/0x360
[  212.976973]  ? rwlock_bug.part.0+0x60/0x60
[  212.981548]  ? __mod_node_page_state+0x1f/0xa0
[  212.986060]  ? match_held_lock+0x1b/0x240
[  212.990567]  ? find_held_lock+0x85/0xa0
[  212.994989]  ? do_user_addr_fault+0x349/0x5b0
[  212.999387]  ? lock_downgrade+0x360/0x360
[  213.003713]  ? find_held_lock+0x85/0xa0
[  213.007972]  ? __fget_light+0xa1/0xf0
[  213.012143]  ? sockfd_lookup_light+0x91/0xb0
[  213.016165]  __sys_sendmsg+0xba/0x130
[  213.020040]  ? __sys_sendmsg_sock+0xb0/0xb0
[  213.023870]  ? handle_mm_fault+0x337/0x470
[  213.027592]  ? page_fault+0x8/0x30
[  213.031316]  ? lockdep_hardirqs_off+0xbe/0x100
[  213.034999]  ? mark_held_locks+0x24/0x90
[  213.038671]  ? do_syscall_64+0x1e/0xe0
[  213.042297]  do_syscall_64+0x74/0xe0
[  213.045828]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  213.049354] RIP: 0033:0x7fe7c527c7b8
[  213.052792] Code: 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 65 8f 0c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d 00 f
0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83 ec 28 89 54
[  213.060269] RSP: 002b:00007ffc3f7908a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
[  213.064144] RAX: ffffffffffffffda RBX: 000000005d34716f RCX: 00007fe7c527c7b8
[  213.068094] RDX: 0000000000000000 RSI: 00007ffc3f790910 RDI: 0000000000000003
[  213.072109] RBP: 0000000000000000 R08: 0000000000000001 R09: 00007fe7c5340cc0
[  213.076113] R10: 0000000000404ec2 R11: 0000000000000246 R12: 0000000000000080
[  213.080146] R13: 0000000000480640 R14: 0000000000000080 R15: 0000000000000000
[  213.084147] Modules linked in: act_gact cls_flower sch_ingress nfsv3 nfs_acl nfs lockd grace fscache bridge stp llc sunrpc intel_rapl_msr intel_rapl_common
[<1;69;32Msb_edac rdma_ucm rdma_cm x86_pkg_temp_thermal iw_cm intel_powerclamp ib_cm coretemp kvm_intel kvm irqbypass mlx5_ib ib_uverbs ib_core crct10dif_pclmul crc32_pc
lmul crc32c_intel ghash_clmulni_intel mlx5_core intel_cstate intel_uncore iTCO_wdt igb iTCO_vendor_support mlxfw mei_me ptp ses intel_rapl_perf mei pcspkr ipmi
_ssif i2c_i801 joydev enclosure pps_core lpc_ich ioatdma wmi dca ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter acpi_pad ast i2c_algo_bit drm_vram_helpe
r ttm drm_kms_helper drm mpt3sas raid_class scsi_transport_sas
[  213.112326] CR2: 0000000000000010
[  213.117429] ---[ end trace adb58eb0a4ee6283 ]---

Verify that q pointer is not NULL before setting the 'flags' field.

Fixes: 3f05e688 ("net_sched: unset TCQ_F_CAN_BYPASS when adding filters")
Signed-off-by: default avatarVlad Buslov <vladbu@mellanox.com>
Acked-by: default avatarJiri Pirko <jiri@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      60e9babf
    • Kuo-Hsin Yang's avatar
      mm: vmscan: scan anonymous pages on file refaults · c1d98b76
      Kuo-Hsin Yang authored 
      commit 2c012a4a upstream.

When file refaults are detected and there are many inactive file pages,
the system never reclaim anonymous pages, the file pages are dropped
aggressively when there are still a lot of cold anonymous pages and
system thrashes.  This issue impacts the performance of applications
with large executable, e.g.  chrome.

With this patch, when file refault is detected, inactive_list_is_low()
always returns true for file pages in get_scan_count() to enable
scanning anonymous pages.

The problem can be reproduced by the following test program.

---8<---
void fallocate_file(const char *filename, off_t size)
{
	struct stat st;
	int fd;

	if (!stat(filename, &st) && st.st_size >= size)
		return;

	fd = open(filename, O_WRONLY | O_CREAT, 0600);
	if (fd < 0) {
		perror("create file");
		exit(1);
	}
	if (posix_fallocate(fd, 0, size)) {
		perror("fallocate");
		exit(1);
	}
	close(fd);
}

long *alloc_anon(long size)
{
	long *start = malloc(size);
	memset(start, 1, size);
	return start;
}

long access_file(const char *filename, long size, long rounds)
{
	int fd, i;
	volatile char *start1, *end1, *start2;
	const int page_size = getpagesize();
	long sum = 0;

	fd = open(filename, O_RDONLY);
	if (fd == -1) {
		perror("open");
		exit(1);
	}

	/*
	 * Some applications, e.g. chrome, use a lot of executable file
	 * pages, map some of the pages with PROT_EXEC flag to simulate
	 * the behavior.
	 */
	start1 = mmap(NULL, size / 2, PROT_READ | PROT_EXEC, MAP_SHARED,
		      fd, 0);
	if (start1 == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}
	end1 = start1 + size / 2;

	start2 = mmap(NULL, size / 2, PROT_READ, MAP_SHARED, fd, size / 2);
	if (start2 == MAP_FAILED) {
		perror("mmap");
		exit(1);
	}

	for (i = 0; i < rounds; ++i) {
		struct timeval before, after;
		volatile char *ptr1 = start1, *ptr2 = start2;
		gettimeofday(&before, NULL);
		for (; ptr1 < end1; ptr1 += page_size, ptr2 += page_size)
			sum += *ptr1 + *ptr2;
		gettimeofday(&after, NULL);
		printf("File access time, round %d: %f (sec)
", i,
		       (after.tv_sec - before.tv_sec) +
		       (after.tv_usec - before.tv_usec) / 1000000.0);
	}
	return sum;
}

int main(int argc, char *argv[])
{
	const long MB = 1024 * 1024;
	long anon_mb, file_mb, file_rounds;
	const char filename[] = "large";
	long *ret1;
	long ret2;

	if (argc != 4) {
		printf("usage: thrash ANON_MB FILE_MB FILE_ROUNDS
");
		exit(0);
	}
	anon_mb = atoi(argv[1]);
	file_mb = atoi(argv[2]);
	file_rounds = atoi(argv[3]);

	fallocate_file(filename, file_mb * MB);
	printf("Allocate %ld MB anonymous pages
", anon_mb);
	ret1 = alloc_anon(anon_mb * MB);
	printf("Access %ld MB file pages
", file_mb);
	ret2 = access_file(filename, file_mb * MB, file_rounds);
	printf("Print result to prevent optimization: %ld
",
	       *ret1 + ret2);
	return 0;
}
---8<---

Running the test program on 2GB RAM VM with kernel 5.2.0-rc5, the program
fills ram with 2048 MB memory, access a 200 MB file for 10 times.  Without
this patch, the file cache is dropped aggresively and every access to the
file is from disk.

  $ ./thrash 2048 200 10
  Allocate 2048 MB anonymous pages
  Access 200 MB file pages
  File access time, round 0: 2.489316 (sec)
  File access time, round 1: 2.581277 (sec)
  File access time, round 2: 2.487624 (sec)
  File access time, round 3: 2.449100 (sec)
  File access time, round 4: 2.420423 (sec)
  File access time, round 5: 2.343411 (sec)
  File access time, round 6: 2.454833 (sec)
  File access time, round 7: 2.483398 (sec)
  File access time, round 8: 2.572701 (sec)
  File access time, round 9: 2.493014 (sec)

With this patch, these file pages can be cached.

  $ ./thrash 2048 200 10
  Allocate 2048 MB anonymous pages
  Access 200 MB file pages
  File access time, round 0: 2.475189 (sec)
  File access time, round 1: 2.440777 (sec)
  File access time, round 2: 2.411671 (sec)
  File access time, round 3: 1.955267 (sec)
  File access time, round 4: 0.029924 (sec)
  File access time, round 5: 0.000808 (sec)
  File access time, round 6: 0.000771 (sec)
  File access time, round 7: 0.000746 (sec)
  File access time, round 8: 0.000738 (sec)
  File access time, round 9: 0.000747 (sec)

Checked the swap out stats during the test [1], 19006 pages swapped out
with this patch, 3418 pages swapped out without this patch. There are
more swap out, but I think it's within reasonable range when file backed
data set doesn't fit into the memory.

$ ./thrash 2000 100 2100 5 1 # ANON_MB FILE_EXEC FILE_NOEXEC ROUNDS
PROCESSES Allocate 2000 MB anonymous pages active_anon: 1613644,
inactive_anon: 348656, active_file: 892, inactive_file: 1384 (kB)
pswpout: 7972443, pgpgin: 478615246 Access 100 MB executable file pages
Access 2100 MB regular file pages File access time, round 0: 12.165,
(sec) active_anon: 1433788, inactive_anon: 478116, active_file: 17896,
inactive_file: 24328 (kB) File access time, round 1: 11.493, (sec)
active_anon: 1430576, inactive_anon: 477144, active_file: 25440,
inactive_file: 26172 (kB) File access time, round 2: 11.455, (sec)
active_anon: 1427436, inactive_anon: 476060, active_file: 21112,
inactive_file: 28808 (kB) File access time, round 3: 11.454, (sec)
active_anon: 1420444, inactive_anon: 473632, active_file: 23216,
inactive_file: 35036 (kB) File access time, round 4: 11.479, (sec)
active_anon: 1413964, inactive_anon: 471460, active_file: 31728,
inactive_file: 32224 (kB) pswpout: 7991449 (+ 19006), pgpgin: 489924366
(+ 11309120)

With 4 processes accessing non-overlapping parts of a large file, 30316
pages swapped out with this patch, 5152 pages swapped out without this
patch.  The swapout number is small comparing to pgpgin.

[1]: https://github.com/vovo/testing/blob/master/mem_thrash.c

Link: http://lkml.kernel.org/r/20190701081038.GA83398@google.com
Fixes: e9868505 ("mm,vmscan: only evict file pages when we have plenty")
Fixes: 7c5bd705 ("mm: memcg: only evict file pages when we have plenty")
Signed-off-by: default avatarKuo-Hsin Yang <vovoy@chromium.org>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sonny Rao <sonnyrao@chromium.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>	[4.12+]
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
[backported to 4.14.y, 4.19.y, 5.1.y: adjust context]
Signed-off-by: default avatarKuo-Hsin Yang <vovoy@chromium.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c1d98b76
    • Jan Kiszka's avatar
      KVM: nVMX: Clear pending KVM_REQ_GET_VMCS12_PAGES when leaving nested · 7560e333
      Jan Kiszka authored 
      commit cf64527b upstream.

Letting this pend may cause nested_get_vmcs12_pages to run against an
invalid state, corrupting the effective vmcs of L1.

This was triggerable in QEMU after a guest corruption in L2, followed by
a L1 reset.
Signed-off-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: default avatarLiran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Fixes: 7f7f1ba3 ("KVM: x86: do not load vmcs12 pages while still in SMM")
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      7560e333
    • Paolo Bonzini's avatar
      KVM: nVMX: do not use dangling shadow VMCS after guest reset · 967bc679
      Paolo Bonzini authored 
      commit 88dddc11 upstream.

If a KVM guest is reset while running a nested guest, free_nested will
disable the shadow VMCS execution control in the vmcs01.  However,
on the next KVM_RUN vmx_vcpu_run would nevertheless try to sync
the VMCS12 to the shadow VMCS which has since been freed.

This causes a vmptrld of a NULL pointer on my machime, but Jan reports
the host to hang altogether.  Let's see how much this trivial patch fixes.
Reported-by: default avatarJan Kiszka <jan.kiszka@siemens.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      967bc679
    • Theodore Ts'o's avatar
      ext4: allow directory holes · 3a17ca86
      Theodore Ts'o authored 
      commit 4e19d6b6 upstream.

The largedir feature was intended to allow ext4 directories to have
unmapped directory blocks (e.g., directory holes).  And so the
released e2fsprogs no longer enforces this for largedir file systems;
however, the corresponding change to the kernel-side code was not made.

This commit fixes this oversight.
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3a17ca86
    • Ross Zwisler's avatar
      ext4: use jbd2_inode dirty range scoping · caa4e082
      Ross Zwisler authored 
      commit 73131fbb upstream.

Use the newly introduced jbd2_inode dirty range scoping to prevent us
from waiting forever when trying to complete a journal transaction.
Signed-off-by: default avatarRoss Zwisler <zwisler@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      caa4e082
    • Ross Zwisler's avatar
      jbd2: introduce jbd2_inode dirty range scoping · af3812b6
      Ross Zwisler authored 
      commit 6ba0e7dc upstream.

Currently both journal_submit_inode_data_buffers() and
journal_finish_inode_data_buffers() operate on the entire address space
of each of the inodes associated with a given journal entry.  The
consequence of this is that if we have an inode where we are constantly
appending dirty pages we can end up waiting for an indefinite amount of
time in journal_finish_inode_data_buffers() while we wait for all the
pages under writeback to be written out.

The easiest way to cause this type of workload is do just dd from
/dev/zero to a file until it fills the entire filesystem.  This can
cause journal_finish_inode_data_buffers() to wait for the duration of
the entire dd operation.

We can improve this situation by scoping each of the inode dirty ranges
associated with a given transaction.  We do this via the jbd2_inode
structure so that the scoping is contained within jbd2 and so that it
follows the lifetime and locking rules for that structure.

This allows us to limit the writeback & wait in
journal_submit_inode_data_buffers() and
journal_finish_inode_data_buffers() respectively to the dirty range for
a given struct jdb2_inode, keeping us from waiting forever if the inode
in question is still being appended to.
Signed-off-by: default avatarRoss Zwisler <zwisler@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      af3812b6
    • Ross Zwisler's avatar
      mm: add filemap_fdatawait_range_keep_errors() · 4becd6c1
      Ross Zwisler authored 
      commit aa0bfcd9 upstream.

In the spirit of filemap_fdatawait_range() and
filemap_fdatawait_keep_errors(), introduce
filemap_fdatawait_range_keep_errors() which both takes a range upon
which to wait and does not clear errors from the address space.
Signed-off-by: default avatarRoss Zwisler <zwisler@google.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4becd6c1
    • Theodore Ts'o's avatar
      ext4: enforce the immutable flag on open files · c9ea4620
      Theodore Ts'o authored 
      commit 02b016ca upstream.

According to the chattr man page, "a file with the 'i' attribute
cannot be modified..."  Historically, this was only enforced when the
file was opened, per the rest of the description, "... and the file
can not be opened in write mode".

There is general agreement that we should standardize all file systems
to prevent modifications even for files that were opened at the time
the immutable flag is set.  Eventually, a change to enforce this at
the VFS layer should be landing in mainline.  Until then, enforce this
at the ext4 level to prevent xfstests generic/553 from failing.
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>
Cc: stable@kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c9ea4620
    • Darrick J. Wong's avatar
      ext4: don't allow any modifications to an immutable file · 29171e82
      Darrick J. Wong authored 
      commit 2e538403 upstream.

Don't allow any modifications to a file that's marked immutable, which
means that we have to flush all the writable pages to make the readonly
and we have to check the setattr/setflags parameters more closely.
Signed-off-by: default avatarDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      29171e82
    • Peter Zijlstra's avatar
      perf/core: Fix race between close() and fork() · 4a5cc64d
      Peter Zijlstra authored 
      commit 1cf8dfe8 upstream.

Syzcaller reported the following Use-after-Free bug:

	close()						clone()

							  copy_process()
							    perf_event_init_task()
							      perf_event_init_context()
							        mutex_lock(parent_ctx->mutex)
								inherit_task_group()
								  inherit_group()
								    inherit_event()
								      mutex_lock(event->child_mutex)
								      // expose event on child list
								      list_add_tail()
								      mutex_unlock(event->child_mutex)
							        mutex_unlock(parent_ctx->mutex)

							    ...
							    goto bad_fork_*

							  bad_fork_cleanup_perf:
							    perf_event_free_task()

	  perf_release()
	    perf_event_release_kernel()
	      list_for_each_entry()
		mutex_lock(ctx->mutex)
		mutex_lock(event->child_mutex)
		// event is from the failing inherit
		// on the other CPU
		perf_remove_from_context()
		list_move()
		mutex_unlock(event->child_mutex)
		mutex_unlock(ctx->mutex)

							      mutex_lock(ctx->mutex)
							      list_for_each_entry_safe()
							        // event already stolen
							      mutex_unlock(ctx->mutex)

							    delayed_free_task()
							      free_task()

	     list_for_each_entry_safe()
	       list_del()
	       free_event()
	         _free_event()
		   // and so event->hw.target
		   // is the already freed failed clone()
		   if (event->hw.target)
		     put_task_struct(event->hw.target)
		       // WHOOPSIE, already quite dead

Which puts the lie to the the comment on perf_event_free_task():
'unexposed, unused context' not so much.

Which is a 'fun' confluence of fail; copy_process() doing an
unconditional free_task() and not respecting refcounts, and perf having
creative locking. In particular:

  82d94856 ("perf/core: Fix lock inversion between perf,trace,cpuhp")

seems to have overlooked this 'fun' parade.

Solve it by using the fact that detached events still have a reference
count on their (previous) context. With this perf_event_free_task()
can detect when events have escaped and wait for their destruction.
Debugged-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Reported-by: syzbot+a24c397a29ad22d86c98@syzkaller.appspotmail.com
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
Cc: <stable@vger.kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: 82d94856 ("perf/core: Fix lock inversion between perf,trace,cpuhp")
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4a5cc64d
    • Alexander Shishkin's avatar
      perf/core: Fix exclusive events' grouping · 75100ec5
      Alexander Shishkin authored 
      commit 8a58ddae upstream.

So far, we tried to disallow grouping exclusive events for the fear of
complications they would cause with moving between contexts. Specifically,
moving a software group to a hardware context would violate the exclusivity
rules if both groups contain matching exclusive events.

This attempt was, however, unsuccessful: the check that we have in the
perf_event_open() syscall is both wrong (looks at wrong PMU) and
insufficient (group leader may still be exclusive), as can be illustrated
by running:

  $ perf record -e '{intel_pt//,cycles}' uname
  $ perf record -e '{cycles,intel_pt//}' uname

ultimately successfully.

Furthermore, we are completely free to trigger the exclusivity violation
by:

   perf -e '{cycles,intel_pt//}' -e '{intel_pt//,instructions}'

even though the helpful perf record will not allow that, the ABI will.

The warning later in the perf_event_open() path will also not trigger, because
it's also wrong.

Fix all this by validating the original group before moving, getting rid
of broken safeguards and placing a useful one to perf_install_in_context().
Signed-off-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: mathieu.poirier@linaro.org
Cc: will.deacon@arm.com
Fixes: bed5b25a ("perf: Add a pmu capability for "exclusive" events")
Link: https://lkml.kernel.org/r/20190701110755.24646-1-alexander.shishkin@linux.intel.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      75100ec5
    • Paul Cercueil's avatar
      MIPS: lb60: Fix pin mappings · 0e6ef184
      Paul Cercueil authored 
      commit 1323c3b7 upstream.

The pin mappings introduced in commit 636f8ba6
("MIPS: JZ4740: Qi LB60: Add pinctrl configuration for several drivers")
are completely wrong. The pinctrl driver name is incorrect, and the
function and group fields are swapped.

Fixes: 636f8ba6 ("MIPS: JZ4740: Qi LB60: Add pinctrl configuration for several drivers")
Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarPaul Cercueil <paul@crapouillou.net>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarPaul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: od@zcrc.me
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      0e6ef184
    • Keerthy's avatar
      gpio: davinci: silence error prints in case of EPROBE_DEFER · dd5994ab
      Keerthy authored 
      commit 541e4095 upstream.

Silence error prints in case of EPROBE_DEFER. This avoids
multiple/duplicate defer prints during boot.

Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarKeerthy <j-keerthy@ti.com>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      dd5994ab
    • Chris Wilson's avatar
      dma-buf: Discard old fence_excl on retrying get_fences_rcu for realloc · c947cf3e
      Chris Wilson authored 
      commit f5b07b04 upstream.

If we have to drop the seqcount & rcu lock to perform a krealloc, we
have to restart the loop. In doing so, be careful not to lose track of
the already acquired exclusive fence.

Fixes: fedf5413 ("dma-buf: Restart reservation_object_get_fences_rcu() after writes")
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: stable@vger.kernel.org #v4.10
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190604125323.21396-1-chris@chris-wilson.co.ukSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      c947cf3e
    • Jérôme Glisse's avatar
      dma-buf: balance refcount inbalance · 95ee55ca
      Jérôme Glisse authored 
      commit 5e383a97 upstream.

The debugfs take reference on fence without dropping them.
Signed-off-by: default avatarJérôme Glisse <jglisse@redhat.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Cc: Stéphane Marchesin <marcheu@chromium.org>
Cc: stable@vger.kernel.org
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20181206161840.6578-1-jglisse@redhat.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      95ee55ca
    • Nikolay Aleksandrov's avatar
      net: bridge: stp: don't cache eth dest pointer before skb pull · b72fb8de
      Nikolay Aleksandrov authored 
      [ Upstream commit 2446a68a ]

Don't cache eth dest pointer before calling pskb_may_pull.

Fixes: cf0f02d0 ("[BRIDGE]: use llc for receiving STP packets")
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      b72fb8de
    • Nikolay Aleksandrov's avatar
      net: bridge: don't cache ether dest pointer on input · 78701843
      Nikolay Aleksandrov authored 
      [ Upstream commit 3d26eb8a ]

We would cache ether dst pointer on input in br_handle_frame_finish but
after the neigh suppress code that could lead to a stale pointer since
both ipv4 and ipv6 suppress code do pskb_may_pull. This means we have to
always reload it after the suppress code so there's no point in having
it cached just retrieve it directly.

Fixes: 057658cb ("bridge: suppress arp pkts on BR_NEIGH_SUPPRESS ports")
Fixes: ed842fae ("bridge: suppress nd pkts on BR_NEIGH_SUPPRESS ports")
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      78701843
    • Nikolay Aleksandrov's avatar
      net: bridge: mcast: fix stale ipv6 hdr pointer when handling v6 query · 41a8df71
      Nikolay Aleksandrov authored 
      [ Upstream commit 3b26a5d0 ]

We get a pointer to the ipv6 hdr in br_ip6_multicast_query but we may
call pskb_may_pull afterwards and end up using a stale pointer.
So use the header directly, it's just 1 place where it's needed.

Fixes: 08b202b6 ("bridge br_multicast: IPv6 MLD support.")
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Tested-by: default avatarMartin Weinelt <martin@linuxlounge.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      41a8df71
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