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Hengqi Chen ebb09d58df LoongArch: BPF: Don't sign extend memory load operand 
[ Upstream commit fe5757553b ]

The `cgrp_local_storage` test triggers a kernel panic like:

  # ./test_progs -t cgrp_local_storage
  Can't find bpf_testmod.ko kernel module: -2
  WARNING! Selftests relying on bpf_testmod.ko will be skipped.
  [  550.930632] CPU 1 Unable to handle kernel paging request at virtual address 0000000000000080, era == ffff80000200be34, ra == ffff80000200be00
  [  550.931781] Oops[#1]:
  [  550.931966] CPU: 1 PID: 1303 Comm: test_progs Not tainted 6.7.0-rc2-loong-devel-g2f56bb0d2327 #35 a896aca3f4164f09cc346f89f2e09832e07be5f6
  [  550.932215] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
  [  550.932403] pc ffff80000200be34 ra ffff80000200be00 tp 9000000108350000 sp 9000000108353dc0
  [  550.932545] a0 0000000000000000 a1 0000000000000517 a2 0000000000000118 a3 00007ffffbb15558
  [  550.932682] a4 00007ffffbb15620 a5 90000001004e7700 a6 0000000000000021 a7 0000000000000118
  [  550.932824] t0 ffff80000200bdc0 t1 0000000000000517 t2 0000000000000517 t3 00007ffff1c06ee0
  [  550.932961] t4 0000555578ae04d0 t5 fffffffffffffff8 t6 0000000000000004 t7 0000000000000020
  [  550.933097] t8 0000000000000040 u0 00000000000007b8 s9 9000000108353e00 s0 90000001004e7700
  [  550.933241] s1 9000000004005000 s2 0000000000000001 s3 0000000000000000 s4 0000555555eb2ec8
  [  550.933379] s5 00007ffffbb15bb8 s6 00007ffff1dafd60 s7 000055555663f610 s8 00007ffff1db0050
  [  550.933520]    ra: ffff80000200be00 bpf_prog_98f1b9e767be2a84_on_enter+0x40/0x200
  [  550.933911]   ERA: ffff80000200be34 bpf_prog_98f1b9e767be2a84_on_enter+0x74/0x200
  [  550.934105]  CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
  [  550.934596]  PRMD: 00000004 (PPLV0 +PIE -PWE)
  [  550.934712]  EUEN: 00000003 (+FPE +SXE -ASXE -BTE)
  [  550.934836]  ECFG: 00071c1c (LIE=2-4,10-12 VS=7)
  [  550.934976] ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
  [  550.935097]  BADV: 0000000000000080
  [  550.935181]  PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
  [  550.935291] Modules linked in:
  [  550.935391] Process test_progs (pid: 1303, threadinfo=000000006c3b1c41, task=0000000061f84a55)
  [  550.935643] Stack : 00007ffffbb15bb8 0000555555eb2ec8 0000000000000000 0000000000000001
  [  550.935844]         9000000004005000 ffff80001b864000 00007ffffbb15450 90000000029aa034
  [  550.935990]         0000000000000000 9000000108353ec0 0000000000000118 d07d9dfb09721a09
  [  550.936175]         0000000000000001 0000000000000000 9000000108353ec0 0000000000000118
  [  550.936314]         9000000101d46ad0 900000000290abf0 000055555663f610 0000000000000000
  [  550.936479]         0000000000000003 9000000108353ec0 00007ffffbb15450 90000000029d7288
  [  550.936635]         00007ffff1dafd60 000055555663f610 0000000000000000 0000000000000003
  [  550.936779]         9000000108353ec0 90000000035dd1f0 00007ffff1dafd58 9000000002841c5c
  [  550.936939]         0000000000000119 0000555555eea5a8 00007ffff1d78780 00007ffffbb153e0
  [  550.937083]         ffffffffffffffda 00007ffffbb15518 0000000000000040 00007ffffbb15558
  [  550.937224]         ...
  [  550.937299] Call Trace:
  [  550.937521] [<ffff80000200be34>] bpf_prog_98f1b9e767be2a84_on_enter+0x74/0x200
  [  550.937910] [<90000000029aa034>] bpf_trace_run2+0x90/0x154
  [  550.938105] [<900000000290abf0>] syscall_trace_enter.isra.0+0x1cc/0x200
  [  550.938224] [<90000000035dd1f0>] do_syscall+0x48/0x94
  [  550.938319] [<9000000002841c5c>] handle_syscall+0xbc/0x158
  [  550.938477]
  [  550.938607] Code: 580009ae  50016000  262402e4 <28c20085> 14092084  03a00084  16000024  03240084  00150006
  [  550.938851]
  [  550.939021] ---[ end trace 0000000000000000 ]---

Further investigation shows that this panic is triggered by memory
load operations:

  ptr = bpf_cgrp_storage_get(&map_a, task->cgroups->dfl_cgrp, 0,
                             BPF_LOCAL_STORAGE_GET_F_CREATE);

The expression `task->cgroups->dfl_cgrp` involves two memory load.
Since the field offset fits in imm12 or imm14, we use ldd or ldptrd
instructions. But both instructions have the side effect that it will
signed-extended the imm operand. Finally, we got the wrong addresses
and panics is inevitable.

Use a generic ldxd instruction to avoid this kind of issues.

With this change, we have:

  # ./test_progs -t cgrp_local_storage
  Can't find bpf_testmod.ko kernel module: -2
  WARNING! Selftests relying on bpf_testmod.ko will be skipped.
  test_cgrp_local_storage:PASS:join_cgroup /cgrp_local_storage 0 nsec
  #48/1    cgrp_local_storage/tp_btf:OK
  test_attach_cgroup:PASS:skel_open 0 nsec
  test_attach_cgroup:PASS:prog_attach 0 nsec
  test_attach_cgroup:PASS:prog_attach 0 nsec
  libbpf: prog 'update_cookie_tracing': failed to attach: ERROR: strerror_r(-524)=22
  test_attach_cgroup:FAIL:prog_attach unexpected error: -524
  #48/2    cgrp_local_storage/attach_cgroup:FAIL
  test_recursion:PASS:skel_open_and_load 0 nsec
  libbpf: prog 'on_lookup': failed to attach: ERROR: strerror_r(-524)=22
  libbpf: prog 'on_lookup': failed to auto-attach: -524
  test_recursion:FAIL:skel_attach unexpected error: -524 (errno 524)
  #48/3    cgrp_local_storage/recursion:FAIL
  #48/4    cgrp_local_storage/negative:OK
  #48/5    cgrp_local_storage/cgroup_iter_sleepable:OK
  test_yes_rcu_lock:PASS:skel_open 0 nsec
  test_yes_rcu_lock:PASS:skel_load 0 nsec
  libbpf: prog 'yes_rcu_lock': failed to attach: ERROR: strerror_r(-524)=22
  libbpf: prog 'yes_rcu_lock': failed to auto-attach: -524
  test_yes_rcu_lock:FAIL:skel_attach unexpected error: -524 (errno 524)
  #48/6    cgrp_local_storage/yes_rcu_lock:FAIL
  #48/7    cgrp_local_storage/no_rcu_lock:OK
  #48      cgrp_local_storage:FAIL

  All error logs:
  test_cgrp_local_storage:PASS:join_cgroup /cgrp_local_storage 0 nsec
  test_attach_cgroup:PASS:skel_open 0 nsec
  test_attach_cgroup:PASS:prog_attach 0 nsec
  test_attach_cgroup:PASS:prog_attach 0 nsec
  libbpf: prog 'update_cookie_tracing': failed to attach: ERROR: strerror_r(-524)=22
  test_attach_cgroup:FAIL:prog_attach unexpected error: -524
  #48/2    cgrp_local_storage/attach_cgroup:FAIL
  test_recursion:PASS:skel_open_and_load 0 nsec
  libbpf: prog 'on_lookup': failed to attach: ERROR: strerror_r(-524)=22
  libbpf: prog 'on_lookup': failed to auto-attach: -524
  test_recursion:FAIL:skel_attach unexpected error: -524 (errno 524)
  #48/3    cgrp_local_storage/recursion:FAIL
  test_yes_rcu_lock:PASS:skel_open 0 nsec
  test_yes_rcu_lock:PASS:skel_load 0 nsec
  libbpf: prog 'yes_rcu_lock': failed to attach: ERROR: strerror_r(-524)=22
  libbpf: prog 'yes_rcu_lock': failed to auto-attach: -524
  test_yes_rcu_lock:FAIL:skel_attach unexpected error: -524 (errno 524)
  #48/6    cgrp_local_storage/yes_rcu_lock:FAIL
  #48      cgrp_local_storage:FAIL
  Summary: 0/4 PASSED, 0 SKIPPED, 1 FAILED

No panics any more (The test still failed because lack of BPF trampoline
which I am actively working on).

Fixes: 5dc615520c ("LoongArch: Add BPF JIT support")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2023-12-13 18:39:23 +01:00
arch LoongArch: BPF: Don't sign extend memory load operand 2023-12-13 18:39:23 +01:00
block blk-core: use pr_warn_ratelimited() in bio_check_ro() 2023-11-20 11:52:17 +01:00
certs certs: Fix build error when PKCS#11 URI contains semicolon 2023-02-09 11:28:11 +01:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 17:06:58 +00:00
Documentation tee: optee: Fix supplicant based device enumeration 2023-12-13 18:39:12 +01:00
drivers misc: mei: client.c: fix problem of return '-EOVERFLOW' in mei_cl_write 2023-12-13 18:39:23 +01:00
fs nilfs2: prevent WARNING in nilfs_sufile_set_segment_usage() 2023-12-13 18:39:19 +01:00
include hugetlb: fix null-ptr-deref in hugetlb_vma_lock_write 2023-12-13 18:39:20 +01:00
init proc: sysctl: prevent aliased sysctls from getting passed to init 2023-11-28 17:07:08 +00:00
io_uring io_uring: fix mutex_unlock with unreferenced ctx 2023-12-13 18:39:18 +01:00
ipc ipc: fix memory leak in init_mqueue_fs() 2022-12-31 13:32:01 +01:00
kernel tracing: Fix a possible race when disabling buffered events 2023-12-13 18:39:20 +01:00
lib zstd: Fix array-index-out-of-bounds UBSAN warning 2023-12-13 18:39:04 +01:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm mm: fix oops when filemap_map_pmd() without prealloc_pte 2023-12-13 18:39:20 +01:00
net packet: Move reference count in packet_sock to atomic_long_t 2023-12-13 18:39:20 +01:00
rust rust: allocator: Prevent mis-aligned allocation 2023-08-11 12:08:18 +02:00
samples fprobe: Pass entry_data to handlers 2023-10-25 12:03:12 +02:00
scripts checkstack: fix printed address 2023-12-13 18:39:19 +01:00
security ima: detect changes to the backing overlay file 2023-11-28 17:07:12 +00:00
sound ALSA: hda/realtek: Add Framework laptop 16 to quirks 2023-12-13 18:39:18 +01:00
tools selftests/net: mptcp: fix uninitialized variable warnings 2023-12-08 08:51:17 +01:00
usr usr/gen_init_cpio.c: remove unnecessary -1 values from int file 2022-10-03 14:21:44 -07:00
virt kvm/vfio: ensure kvg instance stays around in kvm_vfio_group_add() 2023-09-13 09:42:46 +02:00
.clang-format inet: ping: use hlist_nulls rcu iterator during lookup 2022-12-01 12:42:46 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore get_maintainer: add Alan to .get_maintainer.ignore 2022-08-20 15:17:44 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore Kbuild: add Rust support 2022-09-28 09:02:20 +02:00
.mailmap 9 hotfixes. 6 for MM, 3 for other areas. Four of these patches address 2022-12-10 17:10:52 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove Michal Marek from Kbuild maintainers 2022-11-16 14:53:00 +09:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS devlink: move code to a dedicated directory 2023-08-30 16:11:00 +02:00
Makefile Linux 6.1.67 2023-12-11 10:41:01 +01:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
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In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.