The patch titled Subject: lib/stackdepot.c: ignore junk last entry in case of switch from user mode. has been removed from the -mm tree. Its filename was stackdepot-ignore-junk-last-entry-in-case-of-switch-from-user-mode.patch This patch was dropped because an updated version will be merged ------------------------------------------------------ From: Maninder Singh <maninder1.s@xxxxxxxxxxx> Subject: lib/stackdepot.c: ignore junk last entry in case of switch from user mode. Issue observed on ARM. Whenever there is switch from user mode, we end up with invalid last entry with some user space address as below:- save_stack+0x40/0xec __set_page_owner+0x2c/0x64 .... .... __handle_domain_irq+0x9c/0x130 gic_handle_irq+0x40/0x80 __irq_usr+0x4c/0x60 0xb6507818 So in this case last entry is not valid, which leads to allocated one more new frame for stackdepot although having all above frames exactly same. (It increases depot_index drastically) So its better to ignore that last frame in case of switch. save_stack+0x40/0xec __set_page_owner+0x2c/0x64 .... .... __handle_domain_irq+0x9c/0x130 gic_handle_irq+0x40/0x80 __irq_usr+0x4c/0x60 Link: http://lkml.kernel.org/r/1507725802-44574-1-git-send-email-maninder1.s@xxxxxxxxxxx Signed-off-by: Vaneet Narang <v.narang@xxxxxxxxxxx> Signed-off-by: Maninder Singh <maninder1.s@xxxxxxxxxxx> Cc: Dmitriy Vyukov <dvyukov@xxxxxxxxxx> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Mark Rutland <mark.rutland@xxxxxxx> Cc: Amit Sahrawat <a.sahrawat@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- lib/stackdepot.c | 7 +++++++ 1 file changed, 7 insertions(+) diff -puN lib/stackdepot.c~stackdepot-ignore-junk-last-entry-in-case-of-switch-from-user-mode lib/stackdepot.c --- a/lib/stackdepot.c~stackdepot-ignore-junk-last-entry-in-case-of-switch-from-user-mode +++ a/lib/stackdepot.c @@ -214,6 +214,13 @@ depot_stack_handle_t depot_save_stack(st if (unlikely(trace->nr_entries == 0)) goto fast_exit; + /* + * Ignore last entry if it belongs to user space + * in case of switch from user mode. + */ + if (!kernel_text_address(trace->entries[trace->nr_entries - 1])) + trace->nr_entries--; + hash = hash_stack(trace->entries, trace->nr_entries); bucket = &stack_table[hash & STACK_HASH_MASK]; _ Patches currently in -mm which might be from maninder1.s@xxxxxxxxxxx are bloat-o-meter-provide-3-different-arguments-for-data-function-and-all.patch bloat-o-meter-provide-3-different-arguments-for-data-function-and-all-v2.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html