From 910e230d5f1bb72c54532e94fbb1705095c7bab6 Mon Sep 17 00:00:00 2001 From: Rong Tao Date: Sun, 16 Apr 2023 23:05:17 +0800 Subject: samples/hw_breakpoint: Fix kernel BUG 'invalid opcode: 0000' Macro symbol_put() is defined as __symbol_put(__stringify(x)) ksym_name = "jiffies" symbol_put(ksym_name) will be resolved as __symbol_put("ksym_name") which is clearly wrong. So symbol_put must be replaced with __symbol_put. When we uninstall hw_breakpoint.ko (rmmod), a kernel bug occurs with the following error: [11381.854152] kernel BUG at kernel/module/main.c:779! [11381.854159] invalid opcode: 0000 [#2] PREEMPT SMP PTI [11381.854163] CPU: 8 PID: 59623 Comm: rmmod Tainted: G D OE 6.2.9-200.fc37.x86_64 #1 [11381.854167] Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./B360M-HDV, BIOS P3.20 10/23/2018 [11381.854169] RIP: 0010:__symbol_put+0xa2/0xb0 [11381.854175] Code: 00 e8 92 d2 f7 ff 65 8b 05 c3 2f e6 78 85 c0 74 1b 48 8b 44 24 30 65 48 2b 04 25 28 00 00 00 75 12 48 83 c4 38 c3 cc cc cc cc <0f> 0b 0f 1f 44 00 00 eb de e8 c0 df d8 00 90 90 90 90 90 90 90 90 [11381.854178] RSP: 0018:ffffad8ec6ae7dd0 EFLAGS: 00010246 [11381.854181] RAX: 0000000000000000 RBX: ffffffffc1fd1240 RCX: 000000000000000c [11381.854184] RDX: 000000000000006b RSI: ffffffffc02bf7c7 RDI: ffffffffc1fd001c [11381.854186] RBP: 000055a38b76e7c8 R08: ffffffff871ccfe0 R09: 0000000000000000 [11381.854188] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [11381.854190] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [11381.854192] FS: 00007fbf7c62c740(0000) GS:ffff8c5badc00000(0000) knlGS:0000000000000000 [11381.854195] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [11381.854197] CR2: 000055a38b7793f8 CR3: 0000000363e1e001 CR4: 00000000003726e0 [11381.854200] DR0: ffffffffb3407980 DR1: 0000000000000000 DR2: 0000000000000000 [11381.854202] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [11381.854204] Call Trace: [11381.854207] [11381.854212] s_module_exit+0xc/0xff0 [symbol_getput] [11381.854219] __do_sys_delete_module.constprop.0+0x198/0x2f0 [11381.854225] do_syscall_64+0x58/0x80 [11381.854231] ? exit_to_user_mode_prepare+0x180/0x1f0 [11381.854237] ? syscall_exit_to_user_mode+0x17/0x40 [11381.854241] ? do_syscall_64+0x67/0x80 [11381.854245] ? syscall_exit_to_user_mode+0x17/0x40 [11381.854248] ? do_syscall_64+0x67/0x80 [11381.854252] ? exc_page_fault+0x70/0x170 [11381.854256] entry_SYSCALL_64_after_hwframe+0x72/0xdc Signed-off-by: Rong Tao Reviewed-by: Petr Mladek Signed-off-by: Luis Chamberlain --- samples/hw_breakpoint/data_breakpoint.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c index 418c46fe5ffc..9debd128b2ab 100644 --- a/samples/hw_breakpoint/data_breakpoint.c +++ b/samples/hw_breakpoint/data_breakpoint.c @@ -70,7 +70,7 @@ fail: static void __exit hw_break_module_exit(void) { unregister_wide_hw_breakpoint(sample_hbp); - symbol_put(ksym_name); + __symbol_put(ksym_name); printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name); } -- cgit v1.2.3 From b9080468caeddc58a91edd1c3a7d212ea82b0d1d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 25 Jul 2023 10:25:36 +0200 Subject: samples/hw_breakpoint: fix building without module unloading __symbol_put() is really meant as an internal helper and is not available when module unloading is disabled, unlike the previously used symbol_put(): samples/hw_breakpoint/data_breakpoint.c: In function 'hw_break_module_exit': samples/hw_breakpoint/data_breakpoint.c:73:9: error: implicit declaration of function '__symbol_put'; did you mean '__symbol_get'? [-Werror=implicit-function-declaration] The hw_break_module_exit() function is not actually used when module unloading is disabled, but it still causes the build failure for an undefined identifier. Enclose this one call in an appropriate #ifdef to clarify what the requirement is. Leaving out the entire exit function would also work but feels less clar in this case. Fixes: 910e230d5f1bb ("samples/hw_breakpoint: Fix kernel BUG 'invalid opcode: 0000'") Fixes: d8a84d33a4954 ("samples/hw_breakpoint: drop use of kallsyms_lookup_name()") Signed-off-by: Arnd Bergmann Reviewed-by: Petr Mladek Signed-off-by: Luis Chamberlain --- samples/hw_breakpoint/data_breakpoint.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'samples') diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c index 9debd128b2ab..b99322f188e5 100644 --- a/samples/hw_breakpoint/data_breakpoint.c +++ b/samples/hw_breakpoint/data_breakpoint.c @@ -70,7 +70,9 @@ fail: static void __exit hw_break_module_exit(void) { unregister_wide_hw_breakpoint(sample_hbp); +#ifdef CONFIG_MODULE_UNLOAD __symbol_put(ksym_name); +#endif printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name); } -- cgit v1.2.3 From 4b49df654cd0d1c3c359fc0f52182943a650b746 Mon Sep 17 00:00:00 2001 From: Chen Jiahao Date: Wed, 26 Jul 2023 10:17:59 +0000 Subject: samples/hw_breakpoint: mark sample_hbp as static There is a sparse warning shown as below: samples/hw_breakpoint/data_breakpoint.c:24:19: warning: symbol 'sample_hbp' was not declared. Should it be static? Since 'sample_hbp' is only called within data_breakpoint.c, mark it as static to fix the warning. Fixes: 44ee63587dce ("percpu: Add __percpu sparse annotations to hw_breakpoint") Signed-off-by: Chen Jiahao Signed-off-by: Luis Chamberlain --- samples/hw_breakpoint/data_breakpoint.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'samples') diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c index b99322f188e5..a2c831e89ce0 100644 --- a/samples/hw_breakpoint/data_breakpoint.c +++ b/samples/hw_breakpoint/data_breakpoint.c @@ -21,7 +21,7 @@ #include #include -struct perf_event * __percpu *sample_hbp; +static struct perf_event * __percpu *sample_hbp; static char ksym_name[KSYM_NAME_LEN] = "jiffies"; module_param_string(ksym, ksym_name, KSYM_NAME_LEN, S_IRUGO); -- cgit v1.2.3