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  1. 31 Jul, 2019 37 commits
  3. 28 Jul, 2019 3 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
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