alistair23-linux

redonkable

Fork of alistair23 Linux kernel for reMarkable from https://github.com/alistair23/linux

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Ilias Apalodimas ecd219c729 arm64: bpf: Fix branch offset in JIT [ Upstream commit `32f6865c7a` ] Running the eBPF test_verifier leads to random errors looking like this: [ 6525.735488] Unexpected kernel BRK exception at EL1 [ 6525.735502] Internal error: ptrace BRK handler: f2000100 [#1] SMP [ 6525.741609] Modules linked in: nls_utf8 cifs libdes libarc4 dns_resolver fscache binfmt_misc nls_ascii nls_cp437 vfat fat aes_ce_blk crypto_simd cryptd aes_ce_cipher ghash_ce gf128mul efi_pstore sha2_ce sha256_arm64 sha1_ce evdev efivars efivarfs ip_tables x_tables autofs4 btrfs blake2b_generic xor xor_neon zstd_compress raid6_pq libcrc32c crc32c_generic ahci xhci_pci libahci xhci_hcd igb libata i2c_algo_bit nvme realtek usbcore nvme_core scsi_mod t10_pi netsec mdio_devres of_mdio gpio_keys fixed_phy libphy gpio_mb86s7x [ 6525.787760] CPU: 3 PID: 7881 Comm: test_verifier Tainted: G W 5.9.0-rc1+ #47 [ 6525.796111] Hardware name: Socionext SynQuacer E-series DeveloperBox, BIOS build #1 Jun 6 2020 [ 6525.804812] pstate: 20000005 (nzCv daif -PAN -UAO BTYPE=--) [ 6525.810390] pc : bpf_prog_c3d01833289b6311_F+0xc8/0x9f4 [ 6525.815613] lr : bpf_prog_d53bb52e3f4483f9_F+0x38/0xc8c [ 6525.820832] sp : ffff8000130cbb80 [ 6525.824141] x29: ffff8000130cbbb0 x28: 0000000000000000 [ 6525.829451] x27: 000005ef6fcbf39b x26: 0000000000000000 [ 6525.834759] x25: ffff8000130cbb80 x24: ffff800011dc7038 [ 6525.840067] x23: ffff8000130cbd00 x22: ffff0008f624d080 [ 6525.845375] x21: 0000000000000001 x20: ffff800011dc7000 [ 6525.850682] x19: 0000000000000000 x18: 0000000000000000 [ 6525.855990] x17: 0000000000000000 x16: 0000000000000000 [ 6525.861298] x15: 0000000000000000 x14: 0000000000000000 [ 6525.866606] x13: 0000000000000000 x12: 0000000000000000 [ 6525.871913] x11: 0000000000000001 x10: ffff8000000a660c [ 6525.877220] x9 : ffff800010951810 x8 : ffff8000130cbc38 [ 6525.882528] x7 : 0000000000000000 x6 : 0000009864cfa881 [ 6525.887836] x5 : 00ffffffffffffff x4 : 002880ba1a0b3e9f [ 6525.893144] x3 : 0000000000000018 x2 : ffff8000000a4374 [ 6525.898452] x1 : 000000000000000a x0 : 0000000000000009 [ 6525.903760] Call trace: [ 6525.906202] bpf_prog_c3d01833289b6311_F+0xc8/0x9f4 [ 6525.911076] bpf_prog_d53bb52e3f4483f9_F+0x38/0xc8c [ 6525.915957] bpf_dispatcher_xdp_func+0x14/0x20 [ 6525.920398] bpf_test_run+0x70/0x1b0 [ 6525.923969] bpf_prog_test_run_xdp+0xec/0x190 [ 6525.928326] __do_sys_bpf+0xc88/0x1b28 [ 6525.932072] __arm64_sys_bpf+0x24/0x30 [ 6525.935820] el0_svc_common.constprop.0+0x70/0x168 [ 6525.940607] do_el0_svc+0x28/0x88 [ 6525.943920] el0_sync_handler+0x88/0x190 [ 6525.947838] el0_sync+0x140/0x180 [ 6525.951154] Code: d4202000 d4202000 d4202000 d4202000 (d4202000) [ 6525.957249] ---[ end trace cecc3f93b14927e2 ]--- The reason is the offset[] creation and later usage, while building the eBPF body. The code currently omits the first instruction, since build_insn() will increase our ctx->idx before saving it. That was fine up until bounded eBPF loops were introduced. After that introduction, offset[0] must be the offset of the end of prologue which is the start of the 1st insn while, offset[n] holds the offset of the end of n-th insn. When "taken loop with back jump to 1st insn" test runs, it will eventually call bpf2a64_offset(-1, 2, ctx). Since negative indexing is permitted, the current outcome depends on the value stored in ctx->offset[-1], which has nothing to do with our array. If the value happens to be 0 the tests will work. If not this error triggers. commit `7c2e988f40` ("bpf: fix x64 JIT code generation for jmp to 1st insn") fixed an indentical bug on x86 when eBPF bounded loops were introduced. So let's fix it by creating the ctx->offset[] differently. Track the beginning of instruction and account for the extra instruction while calculating the arm instruction offsets. Fixes: `2589726d12` ("bpf: introduce bounded loops") Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org> Reported-by: Jiri Olsa <jolsa@kernel.org> Co-developed-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Co-developed-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org> Signed-off-by: Yauheni Kaliuta <yauheni.kaliuta@redhat.com> Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org> Acked-by: Will Deacon <will@kernel.org> Link: https://lore.kernel.org/r/20200917084925.177348-1-ilias.apalodimas@linaro.org Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>		2020-09-23 12:40:42 +02:00
Documentation	affs: fix basic permission bits to actually work	2020-09-09 19:12:34 +02:00
LICENSES	LICENSES: Rename other to deprecated	2019-05-03 06:34:32 -06:00
arch	arm64: bpf: Fix branch offset in JIT	2020-09-23 12:40:42 +02:00
block	block: only call sched requeue_request() for scheduled requests	2020-09-23 12:40:37 +02:00
certs	PKCS#7: Refactor verify_pkcs7_signature()	2019-08-05 18:40:18 -04:00
crypto	crypto: af_alg - Work around empty control messages without MSG_MORE	2020-09-03 11:27:05 +02:00
drivers	drm/mediatek: Add missing put_device() call in mtk_hdmi_dt_parse_pdata()	2020-09-23 12:40:42 +02:00
fs	f2fs: Return EOF on unaligned end of file DIO read	2020-09-23 12:40:38 +02:00
include	KVM: MIPS: Change the definition of kvm type	2020-09-23 12:40:38 +02:00
init	x86: Fix early boot crash on gcc-10, third try	2020-05-20 08:20:34 +02:00
ipc	ipc/util.c: sysvipc_find_ipc() incorrectly updates position index	2020-05-20 08:20:16 +02:00
kernel	gcov: add support for GCC 10.1	2020-09-17 13:47:56 +02:00
lib	kobject: Restore old behaviour of kobject_del(NULL)	2020-09-17 13:47:52 +02:00
mm	mm/khugepaged.c: fix khugepaged's request size in collapse_file	2020-09-09 19:12:37 +02:00
net	SUNRPC: stop printk reading past end of string	2020-09-23 12:40:36 +02:00
samples	bpf: Fix fds_example SIGSEGV error	2020-08-19 08:16:03 +02:00
scripts	checkpatch: fix the usage of capture group ( ... )	2020-09-09 19:12:37 +02:00
security	Smack: prevent underflow in smk_set_cipso()	2020-08-19 08:16:16 +02:00
sound	ASoC: meson: axg-toddr: fix channel order on g12 platforms	2020-09-23 12:40:39 +02:00
tools	perf test: Free formats for perf pmu parse test	2020-09-23 12:40:41 +02:00
usr	initramfs: restore default compression behavior	2020-04-08 09:08:38 +02:00
virt	KVM: fix memory leak in kvm_io_bus_unregister_dev()	2020-09-17 13:47:54 +02:00
.clang-format	clang-format: Update with the latest for_each macro list	2019-08-31 10:00:51 +02:00
.cocciconfig	…
.get_maintainer.ignore	Opt out of scripts/get_maintainer.pl	2019-05-16 10:53:40 -07:00
.gitattributes	.gitattributes: set git diff driver for C source code files	2016-10-07 18:46:30 -07:00
.gitignore	Modules updates for v5.4	2019-09-22 10:34:46 -07:00
.mailmap	ARM: SoC fixes	2019-11-10 13:41:59 -08:00
COPYING	COPYING: use the new text with points to the license files	2018-03-23 12:41:45 -06:00
CREDITS	MAINTAINERS: Remove Simon as Renesas SoC Co-Maintainer	2019-10-10 08:12:51 -07:00
Kbuild	kbuild: do not descend to ./Kbuild when cleaning	2019-08-21 21:03:58 +09:00
Kconfig	docs: kbuild: convert docs to ReST and rename to *.rst	2019-06-14 14:21:21 -06:00
MAINTAINERS	Documentation/llvm: add documentation on building w/ Clang/LLVM	2020-08-26 10:40:46 +02:00
Makefile	Linux 5.4.66	2020-09-17 13:47:56 +02:00
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
Documentation/admin-guide/README.rst first.

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.