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Roman Gushchin ca33b8e369 memblock: do not start bottom-up allocations with kernel_end
[ Upstream commit 2dcb3964544177c51853a210b6ad400de78ef17d ]

With kaslr the kernel image is placed at a random place, so starting the
bottom-up allocation with the kernel_end can result in an allocation
failure and a warning like this one:

  hugetlb_cma: reserve 2048 MiB, up to 2048 MiB per node
  ------------[ cut here ]------------
  memblock: bottom-up allocation failed, memory hotremove may be affected
  WARNING: CPU: 0 PID: 0 at mm/memblock.c:332 memblock_find_in_range_node+0x178/0x25a
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 5.10.0+ #1169
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
  RIP: 0010:memblock_find_in_range_node+0x178/0x25a
  Code: e9 6d ff ff ff 48 85 c0 0f 85 da 00 00 00 80 3d 9b 35 df 00 00 75 15 48 c7 c7 c0 75 59 88 c6 05 8b 35 df 00 01 e8 25 8a fa ff <0f> 0b 48 c7 44 24 20 ff ff ff ff 44 89 e6 44 89 ea 48 c7 c1 70 5c
  RSP: 0000:ffffffff88803d18 EFLAGS: 00010086 ORIG_RAX: 0000000000000000
  RAX: 0000000000000000 RBX: 0000000240000000 RCX: 00000000ffffdfff
  RDX: 00000000ffffdfff RSI: 00000000ffffffea RDI: 0000000000000046
  RBP: 0000000100000000 R08: ffffffff88922788 R09: 0000000000009ffb
  R10: 00000000ffffe000 R11: 3fffffffffffffff R12: 0000000000000000
  R13: 0000000000000000 R14: 0000000080000000 R15: 00000001fb42c000
  FS:  0000000000000000(0000) GS:ffffffff88f71000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffa080fb401000 CR3: 00000001fa80a000 CR4: 00000000000406b0
  Call Trace:
    memblock_alloc_range_nid+0x8d/0x11e
    cma_declare_contiguous_nid+0x2c4/0x38c
    hugetlb_cma_reserve+0xdc/0x128
    flush_tlb_one_kernel+0xc/0x20
    native_set_fixmap+0x82/0xd0
    flat_get_apic_id+0x5/0x10
    register_lapic_address+0x8e/0x97
    setup_arch+0x8a5/0xc3f
    start_kernel+0x66/0x547
    load_ucode_bsp+0x4c/0xcd
    secondary_startup_64_no_verify+0xb0/0xbb
  random: get_random_bytes called from __warn+0xab/0x110 with crng_init=0
  ---[ end trace f151227d0b39be70 ]---

At the same time, the kernel image is protected with memblock_reserve(),
so we can just start searching at PAGE_SIZE.  In this case the bottom-up
allocation has the same chances to success as a top-down allocation, so
there is no reason to fallback in the case of a failure.  All together it
simplifies the logic.

Link: https://lkml.kernel.org/r/20201217201214.3414100-2-guro@fb.com
Fixes: 8fabc623238e ("powerpc: Ensure that swiotlb buffer is allocated from low memory")
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Wonhyuk Yang <vvghjk1234@gmail.com>
Cc: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-12 12:51:54 +08:00
Documentation KVM: Forbid the use of tagged userspace addresses for memslots 2021-04-12 12:51:44 +08:00
LICENSES Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
arch ARM: dts: sun7i: a20: bananapro: Fix ethernet phy-mode 2021-04-12 12:51:53 +08:00
block Revert "Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT"" 2021-04-12 12:51:49 +08:00
certs Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
crypto crypto: asym_tpm: correct zero out potential secrets 2021-04-12 12:51:10 +08:00
drivers nvmet-tcp: fix out-of-bounds access when receiving multiple h2cdata PDUs 2021-04-12 12:51:53 +08:00
fs rxrpc: Fix deadlock around release of dst cached on udp tunnel 2021-04-12 12:51:53 +08:00
include kthread: Extract KTHREAD_IS_PER_CPU 2021-04-12 12:51:51 +08:00
init exec: Transform exec_update_mutex into a rw_semaphore 2021-04-12 12:51:05 +08:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2021-03-16 16:27:51 +08:00
kernel bpf, cgroup: Fix problematic bounds check 2021-04-12 12:51:52 +08:00
lib lib/raid6: Let $(UNROLL) rules work with macOS userland 2021-04-12 12:51:24 +08:00
mm memblock: do not start bottom-up allocations with kernel_end 2021-04-12 12:51:54 +08:00
net net: lapb: Copy the skb before sending a packet 2021-04-12 12:51:53 +08:00
package generate-rpms: modify the name of the kernel tag for x86 and arm64 2021-04-07 06:53:59 +00:00
samples samples: bpf: Fix lwt_len_hist reusing previous BPF map 2021-03-16 16:42:53 +08:00
scripts depmod: handle the case of /sbin/depmod without /sbin in PATH 2021-04-12 12:51:06 +08:00
security dump_common_audit_data(): fix racy accesses to ->d_name 2021-04-12 12:51:25 +08:00
sound ALSA: hda: Add Cometlake-R PCI ID 2021-04-12 12:51:51 +08:00
tools objtool: Don't fail on missing symbol table 2021-04-12 12:51:51 +08:00
usr Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
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MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2021-03-16 16:34:24 +08:00
Makefile kbuild: enforce -Werror=return-type 2021-04-12 12:51:21 +08:00
README Init Repo base on linux 5.4.32 long term, and add base tlinux kernel interfaces. 2021-03-16 11:01:34 +08:00
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Tencent Linux Kernel 4.0