* UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 @ 2019-11-26 17:55 Meelis Roos 2019-12-02 17:06 ` Peter Zijlstra 0 siblings, 1 reply; 8+ messages in thread From: Meelis Roos @ 2019-11-26 17:55 UTC (permalink / raw) To: LKML, x86 While testing 5.4 on a Dell D600 (32-bit), I noticed the old UBSAN warnings from p6 perf events. I remember having seen these warnings on other p6 era computers too. [ 2.795167] ================================================================================ [ 2.795206] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 [ 2.795235] index 8 is out of range for type 'u64 [8]' [ 2.795265] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-03419-g386403a115f9-dirty #18 [ 2.795266] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 [ 2.795268] Call Trace: [ 2.795283] dump_stack+0x16/0x19 [ 2.795290] ubsan_epilogue+0xb/0x29 [ 2.795293] __ubsan_handle_out_of_bounds.cold+0x43/0x48 [ 2.795299] ? sysfs_add_file_mode_ns+0xad/0x180 [ 2.795304] p6_pmu_event_map+0x3b/0x50 [ 2.795306] is_visible+0x25/0x30 [ 2.795308] ? collect_events+0x150/0x150 [ 2.795310] internal_create_group+0xd8/0x3e0 [ 2.795312] ? collect_events+0x150/0x150 [ 2.795314] internal_create_groups.part.0+0x34/0x80 [ 2.795317] sysfs_create_groups+0x10/0x20 [ 2.795321] device_add+0x536/0x5a0 [ 2.795326] ? kvasprintf_const+0x59/0x90 [ 2.795331] ? kfree_const+0xf/0x30 [ 2.795334] ? kobject_set_name_vargs+0x6a/0xa0 [ 2.795338] pmu_dev_alloc+0x8e/0xe0 [ 2.795344] perf_event_sysfs_init+0x40/0x78 [ 2.795346] ? stack_map_init+0x17/0x17 [ 2.795347] do_one_initcall+0x7a/0x1b3 [ 2.795351] ? do_early_param+0x75/0x75 [ 2.795354] kernel_init_freeable+0x1ae/0x230 [ 2.795357] ? rest_init+0x6d/0x6d [ 2.795359] kernel_init+0x9/0xf3 [ 2.795361] ? rest_init+0x6d/0x6d [ 2.795363] ret_from_fork+0x2e/0x38 [ 2.795364] ================================================================================ [ 2.795396] ================================================================================ [ 2.795427] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 [ 2.795456] load of address (ptrval) with insufficient space [ 2.795483] for an object of type 'const u64' [ 2.795510] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-03419-g386403a115f9-dirty #18 [ 2.795511] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 [ 2.795512] Call Trace: [ 2.795514] dump_stack+0x16/0x19 [ 2.795517] ubsan_epilogue+0xb/0x29 [ 2.795519] ubsan_type_mismatch_common.cold+0xd6/0xdb [ 2.795522] __ubsan_handle_type_mismatch_v1+0x2d/0x40 [ 2.795524] p6_pmu_event_map+0x4b/0x50 [ 2.795525] is_visible+0x25/0x30 [ 2.795527] ? collect_events+0x150/0x150 [ 2.795529] internal_create_group+0xd8/0x3e0 [ 2.795531] ? collect_events+0x150/0x150 [ 2.795533] internal_create_groups.part.0+0x34/0x80 [ 2.795536] sysfs_create_groups+0x10/0x20 [ 2.795537] device_add+0x536/0x5a0 [ 2.795540] ? kvasprintf_const+0x59/0x90 [ 2.795542] ? kfree_const+0xf/0x30 [ 2.795543] ? kobject_set_name_vargs+0x6a/0xa0 [ 2.795546] pmu_dev_alloc+0x8e/0xe0 [ 2.795548] perf_event_sysfs_init+0x40/0x78 [ 2.795550] ? stack_map_init+0x17/0x17 [ 2.795551] do_one_initcall+0x7a/0x1b3 [ 2.795553] ? do_early_param+0x75/0x75 [ 2.795556] kernel_init_freeable+0x1ae/0x230 [ 2.795558] ? rest_init+0x6d/0x6d [ 2.795560] kernel_init+0x9/0xf3 [ 2.795561] ? rest_init+0x6d/0x6d [ 2.795563] ret_from_fork+0x2e/0x38 [ 2.795565] ================================================================================ -- Meelis Roos <mroos@linux.ee> ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-11-26 17:55 UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 Meelis Roos @ 2019-12-02 17:06 ` Peter Zijlstra 2019-12-03 13:39 ` Meelis Roos 0 siblings, 1 reply; 8+ messages in thread From: Peter Zijlstra @ 2019-12-02 17:06 UTC (permalink / raw) To: Meelis Roos Cc: LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland On Tue, Nov 26, 2019 at 07:55:08PM +0200, Meelis Roos wrote: > While testing 5.4 on a Dell D600 (32-bit), I noticed the old UBSAN warnings from p6 perf events. > I remember having seen these warnings on other p6 era computers too. > > [ 2.795167] ================================================================================ > [ 2.795206] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 > [ 2.795235] index 8 is out of range for type 'u64 [8]' > [ 2.795265] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-03419-g386403a115f9-dirty #18 > [ 2.795266] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 > [ 2.795268] Call Trace: > [ 2.795283] dump_stack+0x16/0x19 > [ 2.795290] ubsan_epilogue+0xb/0x29 > [ 2.795293] __ubsan_handle_out_of_bounds.cold+0x43/0x48 > [ 2.795299] ? sysfs_add_file_mode_ns+0xad/0x180 > [ 2.795304] p6_pmu_event_map+0x3b/0x50 > [ 2.795306] is_visible+0x25/0x30 > [ 2.795308] ? collect_events+0x150/0x150 > [ 2.795310] internal_create_group+0xd8/0x3e0 > [ 2.795312] ? collect_events+0x150/0x150 > [ 2.795314] internal_create_groups.part.0+0x34/0x80 > [ 2.795317] sysfs_create_groups+0x10/0x20 > [ 2.795321] device_add+0x536/0x5a0 > [ 2.795326] ? kvasprintf_const+0x59/0x90 > [ 2.795331] ? kfree_const+0xf/0x30 > [ 2.795334] ? kobject_set_name_vargs+0x6a/0xa0 > [ 2.795338] pmu_dev_alloc+0x8e/0xe0 > [ 2.795344] perf_event_sysfs_init+0x40/0x78 > [ 2.795346] ? stack_map_init+0x17/0x17 > [ 2.795347] do_one_initcall+0x7a/0x1b3 > [ 2.795351] ? do_early_param+0x75/0x75 > [ 2.795354] kernel_init_freeable+0x1ae/0x230 > [ 2.795357] ? rest_init+0x6d/0x6d > [ 2.795359] kernel_init+0x9/0xf3 > [ 2.795361] ? rest_init+0x6d/0x6d > [ 2.795363] ret_from_fork+0x2e/0x38 > [ 2.795364] ================================================================================ Does something like so fix it? diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 9a89d98c55bd..f0ab61cd2f68 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1642,9 +1642,12 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = { ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) { - struct perf_pmu_events_attr *pmu_attr = \ + struct perf_pmu_events_attr *pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); - u64 config = x86_pmu.event_map(pmu_attr->id); + u64 config = 0; + + if (pmu_attr->id < x86_pmu.max_events) + config = x86_pmu.event_map(pmu_attr->id); /* string trumps id */ if (pmu_attr->event_str) ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-12-02 17:06 ` Peter Zijlstra @ 2019-12-03 13:39 ` Meelis Roos 2019-12-04 12:15 ` Jiri Olsa 0 siblings, 1 reply; 8+ messages in thread From: Meelis Roos @ 2019-12-03 13:39 UTC (permalink / raw) To: Peter Zijlstra Cc: LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland > Does something like so fix it? Unfortunately not (tested on top of todays git): [ 0.000000] Linux version 5.4.0-11180-g76bb8b05960c-dirty (mroos@d600) (gcc version 9.2.1 20191109 (Debian 9.2.1-19)) #20 Tue Dec 3 15:14:51 EET 2019 [...] [ 8.774201] ================================================================================ [ 8.774256] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 [ 8.774297] index 8 is out of range for type 'u64 [8]' [ 8.774341] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-11180-g76bb8b05960c-dirty #20 [ 8.774345] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 [ 8.774349] Call Trace: [ 8.774368] dump_stack+0x16/0x19 [ 8.774377] ubsan_epilogue+0xb/0x29 [ 8.774384] __ubsan_handle_out_of_bounds.cold+0x43/0x48 [ 8.774396] ? sysfs_add_file_mode_ns+0xad/0x180 [ 8.774406] p6_pmu_event_map+0x3b/0x50 [ 8.774413] is_visible+0x25/0x30 [ 8.774419] ? collect_events+0x150/0x150 [ 8.774425] internal_create_group+0xd8/0x3e0 [ 8.774431] ? collect_events+0x150/0x150 [ 8.774438] internal_create_groups.part.0+0x34/0x80 [ 8.774444] sysfs_create_groups+0x10/0x20 [ 8.774454] device_add+0x62a/0x710 [ 8.774463] ? kvasprintf_const+0x59/0x90 [ 8.774471] ? kfree_const+0xf/0x30 [ 8.774479] ? kobject_set_name_vargs+0x6a/0xa0 [ 8.774489] pmu_dev_alloc+0x8e/0xe0 [ 8.774497] perf_event_sysfs_init+0x40/0x78 [ 8.774503] ? stack_map_init+0x17/0x17 [ 8.774508] do_one_initcall+0x7a/0x1b3 [ 8.774519] ? do_early_param+0x75/0x75 [ 8.774528] kernel_init_freeable+0x1ae/0x230 [ 8.774537] ? rest_init+0x6d/0x6d [ 8.774544] kernel_init+0x9/0xf3 [ 8.774550] ? rest_init+0x6d/0x6d [ 8.774556] ret_from_fork+0x2e/0x38 [ 8.774562] ================================================================================ [ 8.774606] ================================================================================ [ 8.774649] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 [ 8.774690] load of address (ptrval) with insufficient space [ 8.774727] for an object of type 'const u64' [ 8.774765] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-11180-g76bb8b05960c-dirty #20 [ 8.774768] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 [ 8.774771] Call Trace: [ 8.774777] dump_stack+0x16/0x19 [ 8.774783] ubsan_epilogue+0xb/0x29 [ 8.774789] ubsan_type_mismatch_common.cold+0xd6/0xdb [ 8.774797] __ubsan_handle_type_mismatch_v1+0x2d/0x40 [ 8.774804] p6_pmu_event_map+0x4b/0x50 [ 8.774809] is_visible+0x25/0x30 [ 8.774815] ? collect_events+0x150/0x150 [ 8.774820] internal_create_group+0xd8/0x3e0 [ 8.774826] ? collect_events+0x150/0x150 [ 8.774833] internal_create_groups.part.0+0x34/0x80 [ 8.774839] sysfs_create_groups+0x10/0x20 [ 8.774846] device_add+0x62a/0x710 [ 8.774854] ? kvasprintf_const+0x59/0x90 [ 8.774859] ? kfree_const+0xf/0x30 [ 8.774865] ? kobject_set_name_vargs+0x6a/0xa0 [ 8.774873] pmu_dev_alloc+0x8e/0xe0 [ 8.774879] perf_event_sysfs_init+0x40/0x78 [ 8.774884] ? stack_map_init+0x17/0x17 [ 8.774890] do_one_initcall+0x7a/0x1b3 [ 8.774897] ? do_early_param+0x75/0x75 [ 8.774906] kernel_init_freeable+0x1ae/0x230 [ 8.774913] ? rest_init+0x6d/0x6d [ 8.774920] kernel_init+0x9/0xf3 [ 8.774926] ? rest_init+0x6d/0x6d [ 8.774932] ret_from_fork+0x2e/0x38 [ 8.774937] ================================================================================ ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-12-03 13:39 ` Meelis Roos @ 2019-12-04 12:15 ` Jiri Olsa 2019-12-04 15:06 ` Peter Zijlstra 0 siblings, 1 reply; 8+ messages in thread From: Jiri Olsa @ 2019-12-04 12:15 UTC (permalink / raw) To: Meelis Roos Cc: Peter Zijlstra, LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland On Tue, Dec 03, 2019 at 03:39:49PM +0200, Meelis Roos wrote: > > Does something like so fix it? > > Unfortunately not (tested on top of todays git): hi, which p6 model are you seeing this on? how do you trigger that? thanks, jirka > > [ 0.000000] Linux version 5.4.0-11180-g76bb8b05960c-dirty (mroos@d600) (gcc version 9.2.1 20191109 (Debian 9.2.1-19)) #20 Tue Dec 3 15:14:51 EET 2019 > [...] > [ 8.774201] ================================================================================ > [ 8.774256] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 > [ 8.774297] index 8 is out of range for type 'u64 [8]' > [ 8.774341] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-11180-g76bb8b05960c-dirty #20 > [ 8.774345] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 > [ 8.774349] Call Trace: > [ 8.774368] dump_stack+0x16/0x19 > [ 8.774377] ubsan_epilogue+0xb/0x29 > [ 8.774384] __ubsan_handle_out_of_bounds.cold+0x43/0x48 > [ 8.774396] ? sysfs_add_file_mode_ns+0xad/0x180 > [ 8.774406] p6_pmu_event_map+0x3b/0x50 > [ 8.774413] is_visible+0x25/0x30 > [ 8.774419] ? collect_events+0x150/0x150 > [ 8.774425] internal_create_group+0xd8/0x3e0 > [ 8.774431] ? collect_events+0x150/0x150 > [ 8.774438] internal_create_groups.part.0+0x34/0x80 > [ 8.774444] sysfs_create_groups+0x10/0x20 > [ 8.774454] device_add+0x62a/0x710 > [ 8.774463] ? kvasprintf_const+0x59/0x90 > [ 8.774471] ? kfree_const+0xf/0x30 > [ 8.774479] ? kobject_set_name_vargs+0x6a/0xa0 > [ 8.774489] pmu_dev_alloc+0x8e/0xe0 > [ 8.774497] perf_event_sysfs_init+0x40/0x78 > [ 8.774503] ? stack_map_init+0x17/0x17 > [ 8.774508] do_one_initcall+0x7a/0x1b3 > [ 8.774519] ? do_early_param+0x75/0x75 > [ 8.774528] kernel_init_freeable+0x1ae/0x230 > [ 8.774537] ? rest_init+0x6d/0x6d > [ 8.774544] kernel_init+0x9/0xf3 > [ 8.774550] ? rest_init+0x6d/0x6d > [ 8.774556] ret_from_fork+0x2e/0x38 > [ 8.774562] ================================================================================ > [ 8.774606] ================================================================================ > [ 8.774649] UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 > [ 8.774690] load of address (ptrval) with insufficient space > [ 8.774727] for an object of type 'const u64' > [ 8.774765] CPU: 0 PID: 1 Comm: swapper Not tainted 5.4.0-11180-g76bb8b05960c-dirty #20 > [ 8.774768] Hardware name: Dell Computer Corporation Latitude D600 /0X2034, BIOS A16 06/29/2005 > [ 8.774771] Call Trace: > [ 8.774777] dump_stack+0x16/0x19 > [ 8.774783] ubsan_epilogue+0xb/0x29 > [ 8.774789] ubsan_type_mismatch_common.cold+0xd6/0xdb > [ 8.774797] __ubsan_handle_type_mismatch_v1+0x2d/0x40 > [ 8.774804] p6_pmu_event_map+0x4b/0x50 > [ 8.774809] is_visible+0x25/0x30 > [ 8.774815] ? collect_events+0x150/0x150 > [ 8.774820] internal_create_group+0xd8/0x3e0 > [ 8.774826] ? collect_events+0x150/0x150 > [ 8.774833] internal_create_groups.part.0+0x34/0x80 > [ 8.774839] sysfs_create_groups+0x10/0x20 > [ 8.774846] device_add+0x62a/0x710 > [ 8.774854] ? kvasprintf_const+0x59/0x90 > [ 8.774859] ? kfree_const+0xf/0x30 > [ 8.774865] ? kobject_set_name_vargs+0x6a/0xa0 > [ 8.774873] pmu_dev_alloc+0x8e/0xe0 > [ 8.774879] perf_event_sysfs_init+0x40/0x78 > [ 8.774884] ? stack_map_init+0x17/0x17 > [ 8.774890] do_one_initcall+0x7a/0x1b3 > [ 8.774897] ? do_early_param+0x75/0x75 > [ 8.774906] kernel_init_freeable+0x1ae/0x230 > [ 8.774913] ? rest_init+0x6d/0x6d > [ 8.774920] kernel_init+0x9/0xf3 > [ 8.774926] ? rest_init+0x6d/0x6d > [ 8.774932] ret_from_fork+0x2e/0x38 > [ 8.774937] ================================================================================ > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-12-04 12:15 ` Jiri Olsa @ 2019-12-04 15:06 ` Peter Zijlstra 2019-12-04 15:24 ` Jiri Olsa 2019-12-04 19:47 ` Meelis Roos 0 siblings, 2 replies; 8+ messages in thread From: Peter Zijlstra @ 2019-12-04 15:06 UTC (permalink / raw) To: Jiri Olsa Cc: Meelis Roos, LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland On Wed, Dec 04, 2019 at 01:15:40PM +0100, Jiri Olsa wrote: > On Tue, Dec 03, 2019 at 03:39:49PM +0200, Meelis Roos wrote: > > > Does something like so fix it? > > > > Unfortunately not (tested on top of todays git): > > hi, > which p6 model are you seeing this on? > how do you trigger that? Triggers on any p6 model. I hacked up perf and used "qemu-system-x86_64 -cpu pentium2". The below seems to cure things. --- diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 9a89d98c55bd..f17417644665 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -1642,9 +1643,12 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = { ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) { - struct perf_pmu_events_attr *pmu_attr = \ + struct perf_pmu_events_attr *pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr); - u64 config = x86_pmu.event_map(pmu_attr->id); + u64 config = 0; + + if (pmu_attr->id < x86_pmu.max_events) + x86_pmu.event_map(pmu_attr->id); /* string trumps id */ if (pmu_attr->event_str) @@ -1713,6 +1717,9 @@ is_visible(struct kobject *kobj, struct attribute *attr, int idx) { struct perf_pmu_events_attr *pmu_attr; + if (idx >= x86_pmu.max_events) + return 0; + pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr); /* str trumps id */ return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0; ^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-12-04 15:06 ` Peter Zijlstra @ 2019-12-04 15:24 ` Jiri Olsa 2019-12-04 15:44 ` Peter Zijlstra 2019-12-04 19:47 ` Meelis Roos 1 sibling, 1 reply; 8+ messages in thread From: Jiri Olsa @ 2019-12-04 15:24 UTC (permalink / raw) To: Peter Zijlstra Cc: Meelis Roos, LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland On Wed, Dec 04, 2019 at 04:06:56PM +0100, Peter Zijlstra wrote: > On Wed, Dec 04, 2019 at 01:15:40PM +0100, Jiri Olsa wrote: > > On Tue, Dec 03, 2019 at 03:39:49PM +0200, Meelis Roos wrote: > > > > Does something like so fix it? > > > > > > Unfortunately not (tested on top of todays git): > > > > hi, > > which p6 model are you seeing this on? > > how do you trigger that? > > Triggers on any p6 model. I hacked up perf and used "qemu-system-x86_64 > -cpu pentium2". > > The below seems to cure things. > > --- > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > index 9a89d98c55bd..f17417644665 100644 > --- a/arch/x86/events/core.c > +++ b/arch/x86/events/core.c > @@ -1642,9 +1643,12 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = { > > ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) > { > - struct perf_pmu_events_attr *pmu_attr = \ > + struct perf_pmu_events_attr *pmu_attr = ugh, did this do something weird? ;-) > container_of(attr, struct perf_pmu_events_attr, attr); > - u64 config = x86_pmu.event_map(pmu_attr->id); > + u64 config = 0; > + > + if (pmu_attr->id < x86_pmu.max_events) > + x86_pmu.event_map(pmu_attr->id); hum, should this be assigned to config? config = x86_pmu.event_map(pmu_attr->id); jirka > > /* string trumps id */ > if (pmu_attr->event_str) > @@ -1713,6 +1717,9 @@ is_visible(struct kobject *kobj, struct attribute *attr, int idx) > { > struct perf_pmu_events_attr *pmu_attr; > > + if (idx >= x86_pmu.max_events) > + return 0; > + > pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr.attr); > /* str trumps id */ > return pmu_attr->event_str || x86_pmu.event_map(idx) ? attr->mode : 0; > ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-12-04 15:24 ` Jiri Olsa @ 2019-12-04 15:44 ` Peter Zijlstra 0 siblings, 0 replies; 8+ messages in thread From: Peter Zijlstra @ 2019-12-04 15:44 UTC (permalink / raw) To: Jiri Olsa Cc: Meelis Roos, LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland On Wed, Dec 04, 2019 at 04:24:44PM +0100, Jiri Olsa wrote: > > diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c > > index 9a89d98c55bd..f17417644665 100644 > > --- a/arch/x86/events/core.c > > +++ b/arch/x86/events/core.c > > @@ -1642,9 +1643,12 @@ static struct attribute_group x86_pmu_format_group __ro_after_init = { > > > > ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, char *page) > > { > > - struct perf_pmu_events_attr *pmu_attr = \ > > + struct perf_pmu_events_attr *pmu_attr = > > ugh, did this do something weird? ;-) No, but it's weird to explicitly concat the line outside of a macro, so if 'fixed' it. > > container_of(attr, struct perf_pmu_events_attr, attr); > > - u64 config = x86_pmu.event_map(pmu_attr->id); > > + u64 config = 0; > > + > > + if (pmu_attr->id < x86_pmu.max_events) > > + x86_pmu.event_map(pmu_attr->id); > > hum, should this be assigned to config? > > config = x86_pmu.event_map(pmu_attr->id); D'oh... Yes. > > > > /* string trumps id */ > > if (pmu_attr->event_str) ^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 2019-12-04 15:06 ` Peter Zijlstra 2019-12-04 15:24 ` Jiri Olsa @ 2019-12-04 19:47 ` Meelis Roos 1 sibling, 0 replies; 8+ messages in thread From: Meelis Roos @ 2019-12-04 19:47 UTC (permalink / raw) To: Peter Zijlstra, Jiri Olsa Cc: LKML, x86, Arnaldo Carvalho de Melo, Jiri Olsa, Ingo Molnar, Mark Rutland 04.12.19 17:06 Peter Zijlstra wrote: > On Wed, Dec 04, 2019 at 01:15:40PM +0100, Jiri Olsa wrote: >> On Tue, Dec 03, 2019 at 03:39:49PM +0200, Meelis Roos wrote: >>>> Does something like so fix it? >>> >>> Unfortunately not (tested on top of todays git): >> >> hi, >> which p6 model are you seeing this on? >> how do you trigger that? > > Triggers on any p6 model. I hacked up perf and used "qemu-system-x86_64 > -cpu pentium2". > > The below seems to cure things. Yes, works for me on Pentium M. The UBSAN warning is gone and everything seems to work as before. Thank you! -- Meelis Roos <mroos@linux.ee> ^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2019-12-04 19:47 UTC | newest] Thread overview: 8+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2019-11-26 17:55 UBSAN: Undefined behaviour in arch/x86/events/intel/p6.c:116:29 Meelis Roos 2019-12-02 17:06 ` Peter Zijlstra 2019-12-03 13:39 ` Meelis Roos 2019-12-04 12:15 ` Jiri Olsa 2019-12-04 15:06 ` Peter Zijlstra 2019-12-04 15:24 ` Jiri Olsa 2019-12-04 15:44 ` Peter Zijlstra 2019-12-04 19:47 ` Meelis Roos
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