Re: [PATCH v2 2/2] x86/cfi,bpf: Fix BPF JIT call

Jiri Olsa
2023-12-04T17:25:56Z

On Mon, Dec 04, 2023 at 01:52:39PM +0100, Peter Zijlstra wrote:
> On Mon, Dec 04, 2023 at 12:11:28PM +0100, Peter Zijlstra wrote:
> > On Mon, Dec 04, 2023 at 10:13:34AM +0100, Peter Zijlstra wrote:
> >
> > > > Just running test_progs it splats right away:
> > > >
> > > > [ 74.047757] kmemleak: Found object by alias at 0xffffffffa0001d80
> > > > [ 74.048272] CPU: 14 PID: 104 Comm: kworker/14:0 Tainted: G W
> > > > O 6.7.0-rc3-00702-g41c30fec304d-dirty #5241
> > > > [ 74.049118] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> > > > BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
> > > > [ 74.050042] Workqueue: events bpf_prog_free_deferred
> > > > [ 74.050448] Call Trace:
> > > > [ 74.050663] <TASK>
> > > > [ 74.050841] dump_stack_lvl+0x55/0x80
> > > > [ 74.051141] __find_and_remove_object+0xdb/0x110
> > > > [ 74.051521] kmemleak_free+0x41/0x70
> > > > [ 74.051828] vfree+0x36/0x130
> > >
> > > Durr, I'll see if I can get that stuff running locally, and otherwise
> > > play with the robot as you suggested. Thanks!
> >
> > I think it is bpf_jit_binary_pack_hdr(), which is using prog->bpf_func
> > as a start address for the image, instead of jit_data->image.
> >
> > This used to be true, but now it's offset.
> >
> > Let me see what to do about that...
>
> Not the prettiest of things, but the below seems to make the thing
> happy...
>

hyea,
that boots properly for me but gives crash below when running bpf tests

jirka

---
[ 482.145182][ T699] RIP: 0010:bpf_for_each_array_elem+0xbb/0x120
[ 482.145672][ T699] Code: 4c 01 f5 89 5c 24 04 4c 89 e7 48 8d 74 24 04 48 89 ea 4c 89 fd 4c 89 f9 45 31 c0 4d 89 eb 41 ba ef 86 cd 67 45 03 53 f1 74 02 <0f> 0b 41 ff d3 0f 1f 00 48 85 c0 75 0e 48 8d 43 01 41 8b 4c 24 24
[ 482.147221][ T699] RSP: 0018:ffffc900017e3e88 EFLAGS: 00010217
[ 482.147702][ T699] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc900017e3ed8
[ 482.152162][ T699] RDX: ffff888152eb0210 RSI: ffffc900017e3e8c RDI: ffff888152eb0000
[ 482.152770][ T699] RBP: ffffc900017e3ed8 R08: 0000000000000000 R09: 0000000000000000
[ 482.153350][ T699] R10: 000000004704ef28 R11: ffffffffa0012774 R12: ffff888152eb0000
[ 482.153951][ T699] R13: ffffffffa0012774 R14: ffff888152eb0210 R15: ffffc900017e3ed8
[ 482.154554][ T699] FS: 00007fa60d4fdd00(0000) GS:ffff88846d200000(0000) knlGS:0000000000000000
[ 482.155138][ T699] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 482.155564][ T699] CR2: 00007fa60d7d8000 CR3: 00000001502a2005 CR4: 0000000000770ef0
[ 482.156095][ T699] PKRU: 55555554
[ 482.156349][ T699] Call Trace:
[ 482.156596][ T699] <TASK>
[ 482.156816][ T699] ? __die_body+0x68/0xb0
[ 482.157138][ T699] ? die+0xba/0xe0
[ 482.157456][ T699] ? do_trap+0xa5/0x180
[ 482.157826][ T699] ? bpf_for_each_array_elem+0xbb/0x120
[ 482.158277][ T699] ? bpf_for_each_array_elem+0xbb/0x120
[ 482.158711][ T699] ? do_error_trap+0xc4/0x140
[ 482.159052][ T699] ? bpf_for_each_array_elem+0xbb/0x120
[ 482.159506][ T699] ? handle_invalid_op+0x2c/0x40
[ 482.159906][ T699] ? bpf_for_each_array_elem+0xbb/0x120
[ 482.160990][ T699] ? exc_invalid_op+0x38/0x60
[ 482.161375][ T699] ? asm_exc_invalid_op+0x1a/0x20
[ 482.161788][ T699] ? 0xffffffffa0012774
[ 482.162149][ T699] ? 0xffffffffa0012774
[ 482.162513][ T699] ? bpf_for_each_array_elem+0xbb/0x120
[ 482.162905][ T699] bpf_prog_ca45ea7f9cb8ac1a_inner_map+0x94/0x98
[ 482.163471][ T699] bpf_trampoline_6442549234+0x47/0x1000
[ 482.163981][ T699] __x64_sys_getpgid+0x9/0x20
[ 482.164770][ T699] do_syscall_64+0x53/0x110
[ 482.165184][ T699] entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 482.165646][ T699] RIP: 0033:0x7fa60d6c5b4d
[ 482.166005][ T699] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8b 92 0c 00 f7 d8 64 89 01 48
[ 482.169662][ T699] RSP: 002b:00007ffddfcf99e8 EFLAGS: 00000202 ORIG_RAX: 0000000000000079
[ 482.170582][ T699] RAX: ffffffffffffffda RBX: 00007ffddfcf9d98 RCX: 00007fa60d6c5b4d
[ 482.171376][ T699] RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000557baa5ab850
[ 482.172010][ T699] RBP: 00007ffddfcf9b30 R08: 0000000000000000 R09: 0000000000000000
[ 482.172665][ T699] R10: 0000000000000064 R11: 0000000000000202 R12: 0000000000000001
[ 482.173359][ T699] R13: 0000000000000000 R14: 00007fa60d80d000 R15: 0000557ba6ab9790
[ 482.174014][ T699] </TASK>
[ 482.174289][ T699] Modules linked in: bpf_testmod(OE) intel_rapl_msr intel_rapl_common crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel kvm_intel rapl iTCO_wdt iTCO_vendor_support i2c_i801 i2c_smbus lpc_ich drm loop drm_panel_orientation_quirks zram
[ 482.176040][ T699] ---[ end trace 0000000000000000 ]---
[ 482.176534][ T699] RIP: 0010:bpf_for_each_array_elem+0xbb/0x120
[ 482.177215][ T699] Code: 4c 01 f5 89 5c 24 04 4c 89 e7 48 8d 74 24 04 48 89 ea 4c 89 fd 4c 89 f9 45 31 c0 4d 89 eb 41 ba ef 86 cd 67 45 03 53 f1 74 02 <0f> 0b 41 ff d3 0f 1f 00 48 85 c0 75 0e 48 8d 43 01 41 8b 4c 24 24
[ 482.179405][ T699] RSP: 0018:ffffc900017e3e88 EFLAGS: 00010217
[ 482.179971][ T699] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc900017e3ed8
[ 482.180615][ T699] RDX: ffff888152eb0210 RSI: ffffc900017e3e8c RDI: ffff888152eb0000
[ 482.181195][ T699] RBP: ffffc900017e3ed8 R08: 0000000000000000 R09: 0000000000000000
[ 482.181805][ T699] R10: 000000004704ef28 R11: ffffffffa0012774 R12: ffff888152eb0000
[ 482.182411][ T699] R13: ffffffffa0012774 R14: ffff888152eb0210 R15: ffffc900017e3ed8
[ 482.183043][ T699] FS: 00007fa60d4fdd00(0000) GS:ffff88846d200000(0000) knlGS:0000000000000000
[ 482.183753][ T699] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 482.184361][ T699] CR2: 00007fa60d7d8000 CR3: 00000001502a2005 CR4: 0000000000770ef0
[ 482.185649][ T699] PKRU: 55555554
[ 482.185985][ T699] BUG: sleeping function called from invalid context at include/linux/percpu-rwsem.h:49
[ 482.186846][ T699] in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 699, name: test_progs
[ 482.187590][ T699] preempt_count: 0, expected: 0
[ 482.188055][ T699] RCU nest depth: 1, expected: 0
[ 482.188460][ T699] INFO: lockdep is turned off.
[ 482.188861][ T699] CPU: 1 PID: 699 Comm: test_progs Tainted: G D OE 6.7.0-rc3+ #118 bfe8e46ac948d811e03ae3149ad95ea179efe638
[ 482.189821][ T699] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-1.fc38 04/01/2014
[ 482.191140][ T699] Call Trace:
[ 482.191469][ T699] <TASK>
[ 482.191766][ T699] dump_stack_lvl+0xbd/0x120
[ 482.192222][ T699] __might_resched+0x24a/0x280
[ 482.192694][ T699] exit_signals+0x31/0x280
[ 482.193123][ T699] do_exit+0x1a6/0xbb0
[ 482.193511][ T699] ? bpf_trampoline_6442549234+0x47/0x1000
[ 482.194025][ T699] make_task_dead+0x94/0x180
[ 482.194469][ T699] rewind_stack_and_make_dead+0x17/0x20
[ 482.194968][ T699] RIP: 0033:0x7fa60d6c5b4d
[ 482.195399][ T699] Code: c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 8b 92 0c 00 f7 d8 64 89 01 48
[ 482.197082][ T699] RSP: 002b:00007ffddfcf99e8 EFLAGS: 00000202 ORIG_RAX: 0000000000000079
[ 482.197887][ T699] RAX: ffffffffffffffda RBX: 00007ffddfcf9d98 RCX: 00007fa60d6c5b4d
[ 482.198604][ T699] RDX: 0000000000000002 RSI: 0000000000000000 RDI: 0000557baa5ab850
[ 482.199327][ T699] RBP: 00007ffddfcf9b30 R08: 0000000000000000 R09: 0000000000000000
[ 482.200035][ T699] R10: 0000000000000064 R11: 0000000000000202 R12: 0000000000000001
[ 482.200765][ T699] R13: 0000000000000000 R14: 00007fa60d80d000 R15: 0000557ba6ab9790
[ 482.201499][ T699] </TASK>