On 6/13/19 9:15 AM, Joe Lawrence wrote: > On 6/13/19 9:00 AM, Miroslav Benes wrote: >> Hi Joe, >> >> first, I'm sorry for the lack of response so far. >> >> Maybe you've already noticed but the selftests fail. Well, at least in >> my VM. When test_klp_convert1.ko is loaded, the process is killed with >> >> [ 518.041826] BUG: kernel NULL pointer dereference, address: 0000000000000000 >> [ 518.042816] #PF: supervisor read access in kernel mode >> [ 518.043393] #PF: error_code(0x0000) - not-present page >> [ 518.043981] PGD 0 P4D 0 >> [ 518.044185] Oops: 0000 [#1] SMP PTI >> [ 518.044518] CPU: 2 PID: 2255 Comm: insmod Tainted: G O K 5.1.0-klp_convert_v4-193435-g67748576637e #2 >> [ 518.045784] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58-prebuilt.qemu.org 04/01/2014 >> [ 518.046940] RIP: 0010:test_klp_convert_init+0x1c/0x40 [test_klp_convert1] >> [ 518.047611] Code: 1b a0 48 89 c6 e9 a8 c0 f4 e0 0f 1f 40 00 0f 1f 44 00 00 53 48 c7 c7 00 30 1b a0 e8 5e 33 f6 e0 85 c0 89 c3 74 04 89 d8 5b c3 <48> 8b 35 5d ef e4 5f 48 c7 c7 28 20 1b a0 e8 75 c0 f4 e0 e8 6c ff >> [ 518.049779] RSP: 0018:ffffc90000f37cc8 EFLAGS: 00010246 >> [ 518.050243] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000027de0 >> [ 518.050922] RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffff88807ab54f40 >> [ 518.051619] RBP: ffffffffa01b1080 R08: 0000000096efde7a R09: 0000000000000001 >> [ 518.052332] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000ffffffff >> [ 518.053012] R13: 0000000000000000 R14: ffff888078b55000 R15: ffffc90000f37ea0 >> [ 518.053714] FS: 00007febece1fb80(0000) GS:ffff88807d400000(0000) knlGS:0000000000000000 >> [ 518.054514] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> [ 518.055078] CR2: 0000000000000000 CR3: 000000007a56a000 CR4: 00000000000006e0 >> [ 518.055818] Call Trace: >> [ 518.056007] do_one_initcall+0x6a/0x2da >> [ 518.056340] ? do_init_module+0x22/0x230 >> [ 518.056702] ? rcu_read_lock_sched_held+0x96/0xa0 >> [ 518.057125] ? kmem_cache_alloc_trace+0x284/0x2e0 >> [ 518.057493] do_init_module+0x5a/0x230 >> [ 518.057900] load_module+0x17bc/0x1f50 >> [ 518.058214] ? __symbol_put+0x40/0x40 >> [ 518.058499] ? vfs_read+0x12d/0x160 >> [ 518.058766] __do_sys_finit_module+0x83/0xc0 >> [ 518.059122] do_syscall_64+0x57/0x190 >> [ 518.059407] entry_SYSCALL_64_after_hwframe+0x49/0xbe >> ... >> >> It crashes right in test_klp_convert_init() when print_*() using >> supposed-to-be-converted symbols are called. I'll debug it next week. Can >> you reproduce it too? > > Hey, thanks for the report.. > > I don't recall the tests crashing, but I had put this patchset on the > side for a few weeks now. I'll try to fire up a VM and see what happens > today. > Hmm, I haven't been able to reproduce using my original base (Linux 5.1-rc6) or when rebased ontop of livepatching.git/master + 997a55f3fb6d("stacktrace: Unbreak stack_trace_save_tsk_reliable()") FWIW, my test_klp_convert1.ko has these klp-converted relocations: Relocation section [36] '.klp.rela.vmlinux..text.unlikely' for section [ 5] '.text.unlikely' at offset 0x4a6b8 contains 1 entry: Offset Type Value Addend Name 0x0000000000000003 X86_64_PC32 000000000000000000 -4 .klp.sym.vmlinux.saved_command_line,0 Relocation section [37] '.klp.rela.test_klp_convert_mod..text.unlikely' for section [ 5] '.text.unlikely' at offset 0x4a6d0 contains 4 entries: Offset Type Value Addend Name 0x000000000000004e X86_64_PC32 000000000000000000 -4 .klp.sym.test_klp_convert_mod.get_homonym_string,1 0x000000000000003d X86_64_32S 000000000000000000 +0 .klp.sym.test_klp_convert_mod.homonym_string,1 0x0000000000000027 X86_64_PC32 000000000000000000 -4 .klp.sym.test_klp_convert_mod.get_driver_name,0 0x0000000000000016 X86_64_32S 000000000000000000 +0 .klp.sym.test_klp_convert_mod.driver_name,0 -- Joe