3b317abc71
A panic was reported on arm64: [ 44.517109] audit: type=1334 audit(1658859870.268:59): prog-id=19 op=LOAD [ 44.622031] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000010 [ 44.624321] Mem abort info: [ 44.625049] ESR = 0x0000000096000004 [ 44.625935] EC = 0x25: DABT (current EL), IL = 32 bits [ 44.627182] SET = 0, FnV = 0 [ 44.627930] EA = 0, S1PTW = 0 [ 44.628684] FSC = 0x04: level 0 translation fault [ 44.629788] Data abort info: [ 44.630474] ISV = 0, ISS = 0x00000004 [ 44.631362] CM = 0, WnR = 0 [ 44.632041] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000100ab5000 [ 44.633494] [0000000000000010] pgd=0000000000000000, p4d=0000000000000000 [ 44.635202] Internal error: Oops: 96000004 [#1] SMP [ 44.636452] Modules linked in: xfs crct10dif_ce ghash_ce virtio_blk virtio_console virtio_mmio qemu_fw_cfg [ 44.638713] CPU: 2 PID: 1 Comm: systemd Not tainted 5.19.0-rc7 #1 [ 44.640164] Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 [ 44.641799] pstate: 00400005 (nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 44.643404] pc : ftrace_set_filter_ip+0x24/0xa0 [ 44.644659] lr : bpf_trampoline_update.constprop.0+0x428/0x4a0 [ 44.646118] sp : ffff80000803b9f0 [ 44.646950] x29: ffff80000803b9f0 x28: ffff0b5d80364400 x27: ffff80000803bb48 [ 44.648721] x26: ffff8000085ad000 x25: ffff0b5d809d2400 x24: 0000000000000000 [ 44.650493] x23: 00000000ffffffed x22: ffff0b5dd7ea0900 x21: 0000000000000000 [ 44.652279] x20: 0000000000000000 x19: 0000000000000000 x18: ffffffffffffffff [ 44.654067] x17: 0000000000000000 x16: 0000000000000000 x15: ffffffffffffffff [ 44.655787] x14: ffff0b5d809d2498 x13: ffff0b5d809d2432 x12: 0000000005f5e100 [ 44.657535] x11: abcc77118461cefd x10: 000000000000005f x9 : ffffa7219cb5b190 [ 44.659254] x8 : ffffa7219c8e0000 x7 : 0000000000000000 x6 : ffffa7219db075e0 [ 44.661066] x5 : ffffa7219d3130e0 x4 : ffffa7219cab9da0 x3 : 0000000000000000 [ 44.662837] x2 : 0000000000000000 x1 : ffffa7219cb7a5c0 x0 : 0000000000000000 [ 44.664675] Call trace: [ 44.665274] ftrace_set_filter_ip+0x24/0xa0 [ 44.666327] bpf_trampoline_update.constprop.0+0x428/0x4a0 [ 44.667696] __bpf_trampoline_link_prog+0xcc/0x1c0 [ 44.668834] bpf_trampoline_link_prog+0x40/0x64 [ 44.669919] bpf_tracing_prog_attach+0x120/0x490 [ 44.671011] link_create+0xe0/0x2b0 [ 44.671869] __sys_bpf+0x484/0xd30 [ 44.672706] __arm64_sys_bpf+0x30/0x40 [ 44.673678] invoke_syscall+0x78/0x100 [ 44.674623] el0_svc_common.constprop.0+0x4c/0xf4 [ 44.675783] do_el0_svc+0x38/0x4c [ 44.676624] el0_svc+0x34/0x100 [ 44.677429] el0t_64_sync_handler+0x11c/0x150 [ 44.678532] el0t_64_sync+0x190/0x194 [ 44.679439] Code: 2a0203f4 f90013f5 2a0303f5 f9001fe1 (f9400800) [ 44.680959] ---[ end trace 0000000000000000 ]--- [ 44.682111] Kernel panic - not syncing: Oops: Fatal exception [ 44.683488] SMP: stopping secondary CPUs [ 44.684551] Kernel Offset: 0x2721948e0000 from 0xffff800008000000 [ 44.686095] PHYS_OFFSET: 0xfffff4a380000000 [ 44.687144] CPU features: 0x010,00022811,19001080 [ 44.688308] Memory Limit: none [ 44.689082] ---[ end Kernel panic - not syncing: Oops: Fatal exception ]--- It's caused by a NULL tr->fops passed to ftrace_set_filter_ip(). tr->fops is initialized to NULL and is assigned to an allocated memory address if CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS is enabled. Since there is no direct call on arm64 yet, the config can't be enabled. To fix it, call ftrace_set_filter_ip() only if tr->fops is not NULL. Fixes: 00963a2e75a8 ("bpf: Support bpf_trampoline on functions with IPMODIFY (e.g. livepatch)") Reported-by: Bruno Goncalves <bgoncalv@redhat.com> Signed-off-by: Xu Kuohai <xukuohai@huawei.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Tested-by: Bruno Goncalves <bgoncalv@redhat.com> Acked-by: Song Liu <songliubraving@fb.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/bpf/20220728114048.3540461-1-xukuohai@huaweicloud.com
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.