Hi stable maintainers, I recently ran into an issue where trying to load a module with jump table entries crashes the system when function tracing is enabled. The crash happens because ftrace is modifying the code and then marking it as read-only too early. ftrace_make_call() calls module_enable_ro(mod, true) before module init is over because ftrace_module_enable() calls __ftrace_replace_code() which does FTRACE_UPDATE_MAKE_CALL. All this code is gone now upstream but is still present on v5.4 stable kernels. I picked this set of patches to v5.4 and it fixed it for me. fbf6c73c5b26 ftrace: add ftrace_init_nop() a1326b17ac03 module/ftrace: handle patchable-function-entry bd8b21d3dd66 arm64: module: rework special section handling f1a54ae9af0d arm64: module/ftrace: intialize PLT at load time after doing that I ran into another issue because I'm using clang. Would it be possible to pick two more patches to the stable tree to silence this module warning from sysfs complaining about /module/<modname>/sections/__patchable_function_entries being duplicated? dd2776222abb kbuild: lto: merge module sections 6a3193cdd5e5 kbuild: lto: Merge module sections if and only if CONFIG_LTO_CLANG is enabled All of these apply cleanly to v5.4.y stable branch. Crash below. Unable to handle kernel write to read-only memory at virtual address ffffffd1b81fc0b0 Mem abort info: ESR = 0x9600004f EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x0000004f CM = 0, WnR = 1 swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000081bc1000 [ffffffd1b81fc0b0] pgd=0000000271858003, pud=0000000271858003, pmd=0000000266c05003, pte=00600001f3f4df93 Internal error: Oops: 9600004f [#1] PREEMPT SMP Modules linked in: vsock(+) <a bunch more modules> CPU: 5 PID: 6254 Comm: modprobe Not tainted 5.4.177 #19 Hardware name: Google Lazor (rev3 - 8) with KB Backlight (DT) pstate: 60400009 (nZCv daif +PAN -UAO) pc : jump_label_swap+0x2c/0x68 lr : jump_label_swap+0x18/0x68 sp : ffffffc01946bb10 x29: ffffffc01946bb10 x28: 00000000000000b0 x27: 0000000000000010 x26: 00000000000000b0 x25: 00000000000001a0 x24: ffffffd1b81fc180 x23: ffffffd2036540fc x22: ffffffd1b81fc000 x21: 0000000000000010 x20: ffffffd1b81fc0b0 x19: ffffffd1b81fc180 x18: 0000000000000000 x17: ffffffd204006e08 x16: 0000000000006000 x15: ffffffd1b8209000 x14: 0066ba79a6ffffff x13: 0000000000000004 x12: 000000004c55e4d8 x11: 00000000ffffd9f0 x10: 00000000ffffd754 x9 : ffffffffffffff30 x8 : 00000000ffffe2ec x7 : fefefefefefefefe x6 : 00000000000341d5 x5 : ffffffd203654164 x4 : ffffffd2036540fc x3 : 0000000000000000 x2 : ffffffc01946bb30 x1 : ffffffd203654110 x0 : 00000000fffffff0 Call trace: jump_label_swap+0x2c/0x68 do_swap+0x98/0xa0 sort_r+0x178/0x1a0 sort+0x14/0x1c jump_label_module_notify+0x7c/0x2c0 notifier_call_chain+0x58/0x90 __blocking_notifier_call_chain+0x58/0x84 blocking_notifier_call_chain+0x38/0x48 prepare_coming_module+0x30/0x3c load_module+0xda4/0xf8c __arm64_sys_finit_module+0xa4/0xdc el0_svc_common+0xb4/0x17c el0_svc_compat_handler+0x2c/0x58 el0_svc_compat+0x8/0x2c Code: cb130289 29402e8a f940068c 4b090108 (b9000288)
