Fixed overflow bug in binary search for large input. #13

mutexlox · 2011-09-30T03:02:29Z

(left+right)/2 can overflow in the case where left and/or right are large, where left + (right-left)/2 wouldn't.
Example: left=2, right = 2^(32)-1.

commit 3f259d0 upstream. The reiserfs mutex already depends on the inode mutex, so we can't lock the inode mutex in reiserfs_unpack() without using the safe locking API, because reiserfs_unpack() is always called with the reiserfs mutex locked. This fixes: ======================================================= [ INFO: possible circular locking dependency detected ] 2.6.35c torvalds#13 ------------------------------------------------------- lilo/1606 is trying to acquire lock: (&sb->s_type->i_mutex_key#8){+.+.+.}, at: [<d0329450>] reiserfs_unpack+0x60/0x110 [reiserfs] but task is already holding lock: (&REISERFS_SB(s)->lock){+.+.+.}, at: [<d032a268>] reiserfs_write_lock+0x28/0x40 [reiserfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&REISERFS_SB(s)->lock){+.+.+.}: [<c1056347>] lock_acquire+0x67/0x80 [<c12f083d>] __mutex_lock_common+0x4d/0x410 [<c12f0c58>] mutex_lock_nested+0x18/0x20 [<d032a268>] reiserfs_write_lock+0x28/0x40 [reiserfs] [<d0329e9a>] reiserfs_lookup_privroot+0x2a/0x90 [reiserfs] [<d0316b81>] reiserfs_fill_super+0x941/0xe60 [reiserfs] [<c10b7d17>] get_sb_bdev+0x117/0x170 [<d0313e21>] get_super_block+0x21/0x30 [reiserfs] [<c10b74ba>] vfs_kern_mount+0x6a/0x1b0 [<c10b7659>] do_kern_mount+0x39/0xe0 [<c10cebe0>] do_mount+0x340/0x790 [<c10cf0b4>] sys_mount+0x84/0xb0 [<c12f25cd>] syscall_call+0x7/0xb -> #0 (&sb->s_type->i_mutex_key#8){+.+.+.}: [<c1056186>] __lock_acquire+0x1026/0x1180 [<c1056347>] lock_acquire+0x67/0x80 [<c12f083d>] __mutex_lock_common+0x4d/0x410 [<c12f0c58>] mutex_lock_nested+0x18/0x20 [<d0329450>] reiserfs_unpack+0x60/0x110 [reiserfs] [<d0329772>] reiserfs_ioctl+0x272/0x320 [reiserfs] [<c10c3228>] vfs_ioctl+0x28/0xa0 [<c10c3c5d>] do_vfs_ioctl+0x32d/0x5c0 [<c10c3f53>] sys_ioctl+0x63/0x70 [<c12f25cd>] syscall_call+0x7/0xb other info that might help us debug this: 1 lock held by lilo/1606: #0: (&REISERFS_SB(s)->lock){+.+.+.}, at: [<d032a268>] reiserfs_write_lock+0x28/0x40 [reiserfs] stack backtrace: Pid: 1606, comm: lilo Not tainted 2.6.35c torvalds#13 Call Trace: [<c1056186>] __lock_acquire+0x1026/0x1180 [<c1056347>] lock_acquire+0x67/0x80 [<c12f083d>] __mutex_lock_common+0x4d/0x410 [<c12f0c58>] mutex_lock_nested+0x18/0x20 [<d0329450>] reiserfs_unpack+0x60/0x110 [reiserfs] [<d0329772>] reiserfs_ioctl+0x272/0x320 [reiserfs] [<c10c3228>] vfs_ioctl+0x28/0xa0 [<c10c3c5d>] do_vfs_ioctl+0x32d/0x5c0 [<c10c3f53>] sys_ioctl+0x63/0x70 [<c12f25cd>] syscall_call+0x7/0xb Reported-by: Jarek Poplawski <jarkao2@gmail.com> Tested-by: Jarek Poplawski <jarkao2@gmail.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jeff Mahoney <jeffm@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

This patch changes tcm_qla2xxx_drop_tpg() to check for tgt_stop instead of tgt_stopped usage, as tgt_stopped = 1 is expected to be set during normal endpoint shutdown usage. This addresses the following dump_stack() warning during shutdown: [51024.579296] Already in tgt->tgt_stop or tgt_stopped state [51024.585316] Pid: 22371, comm: rmdir Not tainted 2.6.38.3+ torvalds#13 [51024.591754] Call Trace: [51024.594489] [<ffffffffa0308150>] ? qla_tgt_stop_phase1+0x3a/0x27c [qla2xxx] [51024.602350] [<ffffffff810bf56c>] ? free_debug_processing+0x1bd/0x200 [51024.609530] [<ffffffff810d5d5d>] ? dput+0x30/0x14d [51024.614969] [<ffffffffa018dfc5>] ? tcm_qla2xxx_drop_tpg+0x3d/0x6b [tcm_qla2xxx] [51024.623208] [<ffffffffa0105ef2>] ? target_fabric_tpg_release+0x1b/0x1d [target_core_mod] [51024.632327] [<ffffffffa005bd35>] ? config_item_release+0x5a/0x80 [configfs] [51024.640184] [<ffffffffa005bcdb>] ? config_item_release+0x0/0x80 [configfs] [51024.647951] [<ffffffff811aa416>] ? kref_put+0x43/0x4d [51024.653678] [<ffffffffa005bcd9>] ? config_item_put+0x19/0x1b [configfs] [51024.661152] [<ffffffffa005a743>] ? configfs_rmdir+0x1ca/0x231 [configfs] [51024.668712] [<ffffffff810cdcfd>] ? vfs_rmdir+0x7d/0xcb [51024.674540] [<ffffffff810cfce5>] ? do_rmdir+0xa9/0xf8 [51024.680258] [<ffffffff810cfd6b>] ? sys_rmdir+0x11/0x13 [51024.686085] [<ffffffff81002992>] ? system_call_fastpath+0x16/0x1b Reported-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Madhuranath Iyengar <mni@risingtidesystems.com> Signed-off-by: Nicholas Bellinger <nab@risingtidesystems.com>

Overly indented code should be refactored. Suggest refactoring excessive indentation of of if/else/for/do/while/switch statements. For example: $ cat t.c #include <stdio.h> #include <stdlib.h> int main(int argc, char **argv) { if (1) if (2) if (3) if (4) if (5) if (6) if (7) if (8) ; return 0; } $ ./scripts/checkpatch.pl -f t.c WARNING: Too many leading tabs - consider code refactoring #12: FILE: t.c:12: + if (6) WARNING: Too many leading tabs - consider code refactoring #13: FILE: t.c:13: + if (7) WARNING: Too many leading tabs - consider code refactoring #14: FILE: t.c:14: + if (8) total: 0 errors, 3 warnings, 17 lines checked t.c has style problems, please review. If any of these errors are false positives, please report them to the maintainer, see CHECKPATCH in MAINTAINERS. Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If the netdev is already in NETREG_UNREGISTERING/_UNREGISTERED state, do not update the real num tx queues. netdev_queue_update_kobjects() is already called via remove_queue_kobjects() at NETREG_UNREGISTERING time. So, when upper layer driver, e.g., FCoE protocol stack is monitoring the netdev event of NETDEV_UNREGISTER and calls back to LLD ndo_fcoe_disable() to remove extra queues allocated for FCoE, the associated txq sysfs kobjects are already removed, and trying to update the real num queues would cause something like below: ... PID: 25138 TASK: ffff88021e64c440 CPU: 3 COMMAND: "kworker/3:3" #0 [ffff88021f007760] machine_kexec at ffffffff810226d9 #1 [ffff88021f0077d0] crash_kexec at ffffffff81089d2d #2 [ffff88021f0078a0] oops_end at ffffffff813bca78 #3 [ffff88021f0078d0] no_context at ffffffff81029e72 #4 [ffff88021f007920] __bad_area_nosemaphore at ffffffff8102a155 #5 [ffff88021f0079f0] bad_area_nosemaphore at ffffffff8102a23e torvalds#6 [ffff88021f007a00] do_page_fault at ffffffff813bf32e torvalds#7 [ffff88021f007b10] page_fault at ffffffff813bc045 [exception RIP: sysfs_find_dirent+17] RIP: ffffffff81178611 RSP: ffff88021f007bc0 RFLAGS: 00010246 RAX: ffff88021e64c440 RBX: ffffffff8156cc63 RCX: 0000000000000004 RDX: ffffffff8156cc63 RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffff88021f007be0 R8: 0000000000000004 R9: 0000000000000008 R10: ffffffff816fed00 R11: 0000000000000004 R12: 0000000000000000 R13: ffffffff8156cc63 R14: 0000000000000000 R15: ffff8802222a0000 ORIG_RAX: ffffffffffffffff CS: 0010 SS: 0018 torvalds#8 [ffff88021f007be8] sysfs_get_dirent at ffffffff81178c07 torvalds#9 [ffff88021f007c18] sysfs_remove_group at ffffffff8117ac27 torvalds#10 [ffff88021f007c48] netdev_queue_update_kobjects at ffffffff813178f9 torvalds#11 [ffff88021f007c88] netif_set_real_num_tx_queues at ffffffff81303e38 torvalds#12 [ffff88021f007cc8] ixgbe_set_num_queues at ffffffffa0249763 [ixgbe] torvalds#13 [ffff88021f007cf8] ixgbe_init_interrupt_scheme at ffffffffa024ea89 [ixgbe] torvalds#14 [ffff88021f007d48] ixgbe_fcoe_disable at ffffffffa0267113 [ixgbe] torvalds#15 [ffff88021f007d68] vlan_dev_fcoe_disable at ffffffffa014fef5 [8021q] torvalds#16 [ffff88021f007d78] fcoe_interface_cleanup at ffffffffa02b7dfd [fcoe] torvalds#17 [ffff88021f007df8] fcoe_destroy_work at ffffffffa02b7f08 [fcoe] torvalds#18 [ffff88021f007e18] process_one_work at ffffffff8105d7ca torvalds#19 [ffff88021f007e68] worker_thread at ffffffff81060513 torvalds#20 [ffff88021f007ee8] kthread at ffffffff810648b6 torvalds#21 [ffff88021f007f48] kernel_thread_helper at ffffffff813c40f4 Signed-off-by: Yi Zou <yi.zou@intel.com> Tested-by: Ross Brattain <ross.b.brattain@intel.com> Tested-by: Stephen Ko <stephen.s.ko@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 torvalds#6 [d72d3cb4] isolate_migratepages at c030b15a torvalds#7 [d72d3d1] zone_watermark_ok at c02d26cb torvalds#8 [d72d3d2c] compact_zone at c030b8de torvalds#9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d1] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

…S block during isolation for migration BugLink: http://bugs.launchpad.net/bugs/931719 commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 torvalds#6 [d72d3cb4] isolate_migratepages at c030b15a torvalds#7 [d72d3d1] zone_watermark_ok at c02d26cb torvalds#8 [d72d3d2c] compact_zone at c030b8de torvalds#9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

…S block during isolation for migration commit 0bf380b upstream. When isolating for migration, migration starts at the start of a zone which is not necessarily pageblock aligned. Further, it stops isolating when COMPACT_CLUSTER_MAX pages are isolated so migrate_pfn is generally not aligned. This allows isolate_migratepages() to call pfn_to_page() on an invalid PFN which can result in a crash. This was originally reported against a 3.0-based kernel with the following trace in a crash dump. PID: 9902 TASK: d47aecd0 CPU: 0 COMMAND: "memcg_process_s" #0 [d72d3ad0] crash_kexec at c028cfdb #1 [d72d3b24] oops_end at c05c5322 #2 [d72d3b38] __bad_area_nosemaphore at c0227e60 #3 [d72d3bec] bad_area at c0227fb6 #4 [d72d3c00] do_page_fault at c05c72ec #5 [d72d3c80] error_code (via page_fault) at c05c47a4 EAX: 00000000 EBX: 000c0000 ECX: 00000001 EDX: 00000807 EBP: 000c0000 DS: 007b ESI: 00000001 ES: 007b EDI: f3000a80 GS: 6f50 CS: 0060 EIP: c030b15a ERR: ffffffff EFLAGS: 00010002 #6 [d72d3cb4] isolate_migratepages at c030b15a #7 [d72d3d1] zone_watermark_ok at c02d26cb #8 [d72d3d2c] compact_zone at c030b8de #9 [d72d3d68] compact_zone_order at c030bba1 torvalds#10 [d72d3db4] try_to_compact_pages at c030bc84 torvalds#11 [d72d3ddc] __alloc_pages_direct_compact at c02d61e7 torvalds#12 [d72d3e08] __alloc_pages_slowpath at c02d66c7 torvalds#13 [d72d3e78] __alloc_pages_nodemask at c02d6a97 torvalds#14 [d72d3eb8] alloc_pages_vma at c030a845 torvalds#15 [d72d3ed4] do_huge_pmd_anonymous_page at c03178eb torvalds#16 [d72d3f00] handle_mm_fault at c02f36c6 torvalds#17 [d72d3f30] do_page_fault at c05c70ed torvalds#18 [d72d3fb0] error_code (via page_fault) at c05c47a4 EAX: b71ff000 EBX: 00000001 ECX: 00001600 EDX: 00000431 DS: 007b ESI: 08048950 ES: 007b EDI: bfaa3788 SS: 007b ESP: bfaa36e0 EBP: bfaa3828 GS: 6f50 CS: 0073 EIP: 080487c8 ERR: ffffffff EFLAGS: 00010202 It was also reported by Herbert van den Bergh against 3.1-based kernel with the following snippet from the console log. BUG: unable to handle kernel paging request at 01c00008 IP: [<c0522399>] isolate_migratepages+0x119/0x390 *pdpt = 000000002f7ce001 *pde = 0000000000000000 It is expected that it also affects 3.2.x and current mainline. The problem is that pfn_valid is only called on the first PFN being checked and that PFN is not necessarily aligned. Lets say we have a case like this H = MAX_ORDER_NR_PAGES boundary | = pageblock boundary m = cc->migrate_pfn f = cc->free_pfn o = memory hole H------|------H------|----m-Hoooooo|ooooooH-f----|------H The migrate_pfn is just below a memory hole and the free scanner is beyond the hole. When isolate_migratepages started, it scans from migrate_pfn to migrate_pfn+pageblock_nr_pages which is now in a memory hole. It checks pfn_valid() on the first PFN but then scans into the hole where there are not necessarily valid struct pages. This patch ensures that isolate_migratepages calls pfn_valid when necessary. Reported-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Tested-by: Herbert van den Bergh <herbert.van.den.bergh@oracle.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 63de35a upstream. An issue was identified in the dcn21_link_encoder_create function where an out-of-bounds access could occur when the hpd_source index was used to reference the link_enc_hpd_regs array. This array has a fixed size and the index was not being checked against the array's bounds before accessing it. This fix adds a conditional check to ensure that the hpd_source index is within the valid range of the link_enc_hpd_regs array. If the index is out of bounds, the function now returns NULL to prevent undefined behavior. References: [ 65.920507] ------------[ cut here ]------------ [ 65.920510] UBSAN: array-index-out-of-bounds in drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn21/dcn21_resource.c:1312:29 [ 65.920519] index 7 is out of range for type 'dcn10_link_enc_hpd_registers [5]' [ 65.920523] CPU: 3 PID: 1178 Comm: modprobe Tainted: G OE 6.8.0-cleanershaderfeatureresetasdntipmi200nv2132 torvalds#13 [ 65.920525] Hardware name: AMD Majolica-RN/Majolica-RN, BIOS WMJ0429N_Weekly_20_04_2 04/29/2020 [ 65.920527] Call Trace: [ 65.920529] <TASK> [ 65.920532] dump_stack_lvl+0x48/0x70 [ 65.920541] dump_stack+0x10/0x20 [ 65.920543] __ubsan_handle_out_of_bounds+0xa2/0xe0 [ 65.920549] dcn21_link_encoder_create+0xd9/0x140 [amdgpu] [ 65.921009] link_create+0x6d3/0xed0 [amdgpu] [ 65.921355] create_links+0x18a/0x4e0 [amdgpu] [ 65.921679] dc_create+0x360/0x720 [amdgpu] [ 65.921999] ? dmi_matches+0xa0/0x220 [ 65.922004] amdgpu_dm_init+0x2b6/0x2c90 [amdgpu] [ 65.922342] ? console_unlock+0x77/0x120 [ 65.922348] ? dev_printk_emit+0x86/0xb0 [ 65.922354] dm_hw_init+0x15/0x40 [amdgpu] [ 65.922686] amdgpu_device_init+0x26a8/0x33a0 [amdgpu] [ 65.922921] amdgpu_driver_load_kms+0x1b/0xa0 [amdgpu] [ 65.923087] amdgpu_pci_probe+0x1b7/0x630 [amdgpu] [ 65.923087] local_pci_probe+0x4b/0xb0 [ 65.923087] pci_device_probe+0xc8/0x280 [ 65.923087] really_probe+0x187/0x300 [ 65.923087] __driver_probe_device+0x85/0x130 [ 65.923087] driver_probe_device+0x24/0x110 [ 65.923087] __driver_attach+0xac/0x1d0 [ 65.923087] ? __pfx___driver_attach+0x10/0x10 [ 65.923087] bus_for_each_dev+0x7d/0xd0 [ 65.923087] driver_attach+0x1e/0x30 [ 65.923087] bus_add_driver+0xf2/0x200 [ 65.923087] driver_register+0x64/0x130 [ 65.923087] ? __pfx_amdgpu_init+0x10/0x10 [amdgpu] [ 65.923087] __pci_register_driver+0x61/0x70 [ 65.923087] amdgpu_init+0x7d/0xff0 [amdgpu] [ 65.923087] do_one_initcall+0x49/0x310 [ 65.923087] ? kmalloc_trace+0x136/0x360 [ 65.923087] do_init_module+0x6a/0x270 [ 65.923087] load_module+0x1fce/0x23a0 [ 65.923087] init_module_from_file+0x9c/0xe0 [ 65.923087] ? init_module_from_file+0x9c/0xe0 [ 65.923087] idempotent_init_module+0x179/0x230 [ 65.923087] __x64_sys_finit_module+0x5d/0xa0 [ 65.923087] do_syscall_64+0x76/0x120 [ 65.923087] entry_SYSCALL_64_after_hwframe+0x6e/0x76 [ 65.923087] RIP: 0033:0x7f2d80f1e88d [ 65.923087] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 b5 0f 00 f7 d8 64 89 01 48 [ 65.923087] RSP: 002b:00007ffc7bc1aa78 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 [ 65.923087] RAX: ffffffffffffffda RBX: 0000564c9c1db130 RCX: 00007f2d80f1e88d [ 65.923087] RDX: 0000000000000000 RSI: 0000564c9c1e5480 RDI: 000000000000000f [ 65.923087] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000002 [ 65.923087] R10: 000000000000000f R11: 0000000000000246 R12: 0000564c9c1e5480 [ 65.923087] R13: 0000564c9c1db260 R14: 0000000000000000 R15: 0000564c9c1e54b0 [ 65.923087] </TASK> [ 65.923927] ---[ end trace ]--- Cc: Tom Chung <chiahsuan.chung@amd.com> Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Cc: Roman Li <roman.li@amd.com> Cc: Alex Hung <alex.hung@amd.com> Cc: Aurabindo Pillai <aurabindo.pillai@amd.com> Cc: Harry Wentland <harry.wentland@amd.com> Cc: Hamza Mahfooz <hamza.mahfooz@amd.com> Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com> Reviewed-by: Roman Li <roman.li@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Bin Lan <lanbincn@qq.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

WinUSB 版 px4_drv に PX-M1UR / PX-S1UR のサポートを追加

An ioctl caller of SIOCETHTOOL ETHTOOL_GSET can provoke the legacy ethtool codepath on a non-present device, leading to kernel panic: [exception RIP: qed_get_current_link+0x11] torvalds#8 [ffffa2021d70f948] qede_get_link_ksettings at ffffffffc07bfa9a [qede] torvalds#9 [ffffa2021d70f9d0] __rh_call_get_link_ksettings at ffffffff9bad2723 torvalds#10 [ffffa2021d70fa30] ethtool_get_settings at ffffffff9bad29d0 torvalds#11 [ffffa2021d70fb18] __dev_ethtool at ffffffff9bad442b torvalds#12 [ffffa2021d70fc28] dev_ethtool at ffffffff9bad6db8 torvalds#13 [ffffa2021d70fc60] dev_ioctl at ffffffff9ba7a55c torvalds#14 [ffffa2021d70fc98] sock_do_ioctl at ffffffff9ba22a44 torvalds#15 [ffffa2021d70fd08] sock_ioctl at ffffffff9ba22d1c torvalds#16 [ffffa2021d70fd78] do_vfs_ioctl at ffffffff9b584cf4 Device is not present with no state bits set: crash> net_device.state ffff8fff95240000 state = 0x0, Existing patch commit a699781 ("ethtool: check device is present when getting link settings") fixes this in the modern sysfs reader's ksettings path. Fix this in the legacy ioctl path by checking for device presence as well. Fixes: 4bc71cb ("net: consolidate and fix ethtool_ops->get_settings calling") Fixes: 3f1ac7a ("net: ethtool: add new ETHTOOL_xLINKSETTINGS API") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Tested-by: John J Coleman <jjcolemanx86@gmail.com> Co-developed-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Signed-off-by: John J Coleman <jjcolemanx86@gmail.com>

An ioctl caller of SIOCETHTOOL ETHTOOL_GSET can provoke the legacy ethtool codepath on a non-present device, leading to kernel panic: [exception RIP: qed_get_current_link+0x11] torvalds#8 [ffffa2021d70f948] qede_get_link_ksettings at ffffffffc07bfa9a [qede] torvalds#9 [ffffa2021d70f9d0] __rh_call_get_link_ksettings at ffffffff9bad2723 torvalds#10 [ffffa2021d70fa30] ethtool_get_settings at ffffffff9bad29d0 torvalds#11 [ffffa2021d70fb18] __dev_ethtool at ffffffff9bad442b torvalds#12 [ffffa2021d70fc28] dev_ethtool at ffffffff9bad6db8 torvalds#13 [ffffa2021d70fc60] dev_ioctl at ffffffff9ba7a55c torvalds#14 [ffffa2021d70fc98] sock_do_ioctl at ffffffff9ba22a44 torvalds#15 [ffffa2021d70fd08] sock_ioctl at ffffffff9ba22d1c torvalds#16 [ffffa2021d70fd78] do_vfs_ioctl at ffffffff9b584cf4 Device is not present with no state bits set: crash> net_device.state ffff8fff95240000 state = 0x0, Existing patch commit a699781 ("ethtool: check device is present when getting link settings") fixes this in the modern sysfs reader's ksettings path. Fix this in the legacy ioctl path by checking for device presence as well. Fixes: 4bc71cb ("net: consolidate and fix ethtool_ops->get_settings calling") Fixes: 3f1ac7a ("net: ethtool: add new ETHTOOL_xLINKSETTINGS API") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Tested-by: John J Coleman <jjcolemanx86@gmail.com> Co-developed-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com> Signed-off-by: John J Coleman <jjcolemanx86@gmail.com> Signed-off-by: NipaLocal <nipa@local>

t8103: - WLAN (SMC PMU GPIO torvalds#13) t600x: - WLAN (SMC PMU GPIO torvalds#13) - SD (SMC PMU GPIO torvalds#26) Signed-off-by: Hector Martin <marcan@marcan.st>

When a bio with REQ_PREFLUSH is submitted to dm, __send_empty_flush() generates a flush_bio with REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC, which causes the flush_bio to be throttled by wbt_wait(). An example from v5.4, similar problem also exists in upstream: crash> bt 2091206 PID: 2091206 TASK: ffff2050df92a300 CPU: 109 COMMAND: "kworker/u260:0" #0 [ffff800084a2f7f0] __switch_to at ffff80004008aeb8 #1 [ffff800084a2f820] __schedule at ffff800040bfa0c4 #2 [ffff800084a2f880] schedule at ffff800040bfa4b4 #3 [ffff800084a2f8a0] io_schedule at ffff800040bfa9c4 #4 [ffff800084a2f8c0] rq_qos_wait at ffff8000405925bc #5 [ffff800084a2f940] wbt_wait at ffff8000405bb3a0 torvalds#6 [ffff800084a2f9a0] __rq_qos_throttle at ffff800040592254 torvalds#7 [ffff800084a2f9c0] blk_mq_make_request at ffff80004057cf38 torvalds#8 [ffff800084a2fa60] generic_make_request at ffff800040570138 torvalds#9 [ffff800084a2fae0] submit_bio at ffff8000405703b4 torvalds#10 [ffff800084a2fb50] xlog_write_iclog at ffff800001280834 [xfs] torvalds#11 [ffff800084a2fbb0] xlog_sync at ffff800001280c3c [xfs] torvalds#12 [ffff800084a2fbf0] xlog_state_release_iclog at ffff800001280df4 [xfs] torvalds#13 [ffff800084a2fc10] xlog_write at ffff80000128203c [xfs] torvalds#14 [ffff800084a2fcd0] xlog_cil_push at ffff8000012846dc [xfs] torvalds#15 [ffff800084a2fda0] xlog_cil_push_work at ffff800001284a2c [xfs] torvalds#16 [ffff800084a2fdb0] process_one_work at ffff800040111d08 torvalds#17 [ffff800084a2fe00] worker_thread at ffff8000401121cc torvalds#18 [ffff800084a2fe70] kthread at ffff800040118de4 After commit 2def284 ("xfs: don't allow log IO to be throttled"), the metadata submitted by xlog_write_iclog() should not be throttled. But due to the existence of the dm layer, throttling flush_bio indirectly causes the metadata bio to be throttled. Fix this by conditionally adding REQ_IDLE to flush_bio.bi_opf, which makes wbt_should_throttle() return false to avoid wbt_wait(). Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Tianxiang Peng <txpeng@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com>

When a bio with REQ_PREFLUSH is submitted to dm, __send_empty_flush() generates a flush_bio with REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC, which causes the flush_bio to be throttled by wbt_wait(). An example from v5.4, similar problem also exists in upstream: crash> bt 2091206 PID: 2091206 TASK: ffff2050df92a300 CPU: 109 COMMAND: "kworker/u260:0" #0 [ffff800084a2f7f0] __switch_to at ffff80004008aeb8 #1 [ffff800084a2f820] __schedule at ffff800040bfa0c4 #2 [ffff800084a2f880] schedule at ffff800040bfa4b4 #3 [ffff800084a2f8a0] io_schedule at ffff800040bfa9c4 #4 [ffff800084a2f8c0] rq_qos_wait at ffff8000405925bc #5 [ffff800084a2f940] wbt_wait at ffff8000405bb3a0 torvalds#6 [ffff800084a2f9a0] __rq_qos_throttle at ffff800040592254 torvalds#7 [ffff800084a2f9c0] blk_mq_make_request at ffff80004057cf38 torvalds#8 [ffff800084a2fa60] generic_make_request at ffff800040570138 torvalds#9 [ffff800084a2fae0] submit_bio at ffff8000405703b4 torvalds#10 [ffff800084a2fb50] xlog_write_iclog at ffff800001280834 [xfs] torvalds#11 [ffff800084a2fbb0] xlog_sync at ffff800001280c3c [xfs] torvalds#12 [ffff800084a2fbf0] xlog_state_release_iclog at ffff800001280df4 [xfs] torvalds#13 [ffff800084a2fc10] xlog_write at ffff80000128203c [xfs] torvalds#14 [ffff800084a2fcd0] xlog_cil_push at ffff8000012846dc [xfs] torvalds#15 [ffff800084a2fda0] xlog_cil_push_work at ffff800001284a2c [xfs] torvalds#16 [ffff800084a2fdb0] process_one_work at ffff800040111d08 torvalds#17 [ffff800084a2fe00] worker_thread at ffff8000401121cc torvalds#18 [ffff800084a2fe70] kthread at ffff800040118de4 After commit 2def284 ("xfs: don't allow log IO to be throttled"), the metadata submitted by xlog_write_iclog() should not be throttled. But due to the existence of the dm layer, throttling flush_bio indirectly causes the metadata bio to be throttled. Fix this by conditionally adding REQ_IDLE to flush_bio.bi_opf, which makes wbt_should_throttle() return false to avoid wbt_wait(). Signed-off-by: Jinliang Zheng <alexjlzheng@tencent.com> Reviewed-by: Tianxiang Peng <txpeng@tencent.com> Reviewed-by: Hao Peng <flyingpeng@tencent.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

The mbox_chan_received_data() will call Rx callback of mbox client driver using type3 to set the flag of command completion. Then driver can continue to do something like sending a new command. In this case, the rest of the interrupt handler function may be concurrent with pcc_send_data(). The 'chan_in_use' flag of a channel is true after sending a command. And the flag of the new command may be cleared by the running interrupt handler in cornor case. As a result, the interrupt being level triggered can't be cleared in pcc_mbox_irq() and it will be disabled after the number of handled times exceeds the specified value. The error log is as follows: [519082.811553] kunpeng_hccs HISI04B2:00: PCC command executed timeout! [519082.828532] kunpeng_hccs HISI04B2:00: get port link status info failed, ret = -110. [519082.833438] irq 13: nobody cared (try booting with the "irqpoll" option) [519082.844622] CPU: 304 PID: 15206 Comm: systemd-journal Kdump: loaded Tainted: G OE 5.10.0 #5 [519082.854959] Hardware name: To be filled by O.E.M. To be filled by O.E.M./To be filled by O.E.M., BIOS Nezha B800 V3.1.0 01/02/2024 [519082.867467] Call trace: [519082.870709] dump_backtrace+0x0/0x210 [519082.875145] show_stack+0x1c/0x2c [519082.879240] dump_stack+0xec/0x130 [519082.883421] __report_bad_irq+0x50/0x190 [519082.888122] note_interrupt+0x1e4/0x260 [519082.892740] handle_irq_event+0x144/0x17c [519082.897519] handle_fasteoi_irq+0xd0/0x240 [519082.902386] __handle_domain_irq+0x80/0xf0 [519082.907255] gic_handle_irq+0x74/0x2d0 [519082.911774] el1_irq+0xbc/0x140 [519082.915698] mnt_clone_write+0x0/0x70 [519082.920131] file_update_time+0xcc/0x160 [519082.924832] fault_dirty_shared_page+0xe8/0x150 [519082.930133] do_shared_fault+0x80/0x1d0 [519082.934737] do_fault+0x118/0x1a4 [519082.938821] handle_pte_fault+0x154/0x230 [519082.943600] __handle_mm_fault+0x1ac/0x390 [519082.948465] handle_mm_fault+0xf0/0x250 [519082.953075] do_page_fault+0x184/0x454 [519082.957595] do_translation_fault+0xac/0xd4 [519082.962555] do_mem_abort+0x44/0xb4 [519082.966817] el0_da+0x40/0x74 [519082.970554] el0_sync_handler+0x60/0xb4 [519082.975160] el0_sync+0x168/0x180 [519082.979243] handlers: [519082.982300] [<0000000039882697>] pcc_mbox_irq [519082.987433] Disabling IRQ torvalds#13 To solve this issue, pcc_mbox_irq() clear 'chann_in_use' flag immediately after clearing interrupt ack register. Signed-off-by: Huisong Li <lihuisong@huawei.com>

…ge_order() Patch series "mm: MM owner tracking for large folios (!hugetlb) + CONFIG_NO_PAGE_MAPCOUNT", v3. Let's add an "easy" way to decide -- without false positives, without page-mapcounts and without page table/rmap scanning -- whether a large folio is "certainly mapped exclusively" into a single MM, or whether it "maybe mapped shared" into multiple MMs. Use that information to implement Copy-on-Write reuse, to convert folio_likely_mapped_shared() to folio_maybe_mapped_share(), and to introduce a kernel config option that lets us not use+maintain per-page mapcounts in large folios anymore. The bigger picture was presented at LSF/MM [1]. This series is effectively a follow-up on my early work [2], which implemented a more precise, but also more complicated, way to identify whether a large folio is "mapped shared" into multiple MMs or "mapped exclusively" into a single MM. 1 Patch Organization ==================== Patch #1 -> torvalds#6: make more room in order-1 folios, so we have two "unsigned long" available for our purposes Patch torvalds#7 -> torvalds#11: preparations Patch torvalds#12: MM owner tracking for large folios Patch torvalds#13: COW reuse for PTE-mapped anon THP Patch torvalds#14: folio_maybe_mapped_shared() Patch torvalds#15 -> torvalds#20: introduce and implement CONFIG_NO_PAGE_MAPCOUNT 2 MM owner tracking =================== We assign each MM a unique ID ("MM ID"), to be able to squeeze more information in our folios. On 32bit we use 15-bit IDs, on 64bit we use 31-bit IDs. For each large folios, we now store two MM-ID+mapcount ("slot") combinations: * mm0_id + mm0_mapcount * mm1_id + mm1_mapcount On 32bit, we use a 16-bit per-MM mapcount, on 64bit an ordinary 32bit mapcount. This way, we require 2x "unsigned long" on 32bit and 64bit for both slots. Paired with the large mapcount, we can reliably identify whether one of these MMs is the current owner (-> owns all mappings) or even holds all folio references (-> owns all mappings, and all references are from mappings). As long as only two MMs map folio pages at a time, we can reliably and precisely identify whether a large folio is "mapped shared" or "mapped exclusively". Any additional MM that starts mapping the folio while there are no free slots becomes an "untracked MM". If one such "untracked MM" is the last one mapping a folio exclusively, we will not detect the folio as "mapped exclusively" but instead as "maybe mapped shared". (exception: only a single mapping remains) So that's where the approach gets imprecise. For now, we use a bit-spinlock to sync the large mapcount + slots, and make sure we do keep the machinery fast, to not degrade (un)map performance drastically: for example, we make sure to only use a single atomic (when grabbing the bit-spinlock), like we would already perform when updating the large mapcount. 3 CONFIG_NO_PAGE_MAPCOUNT ========================= patch torvalds#15 -> torvalds#20 spell out and document what exactly is affected when not maintaining the per-page mapcounts in large folios anymore. Most importantly, as we cannot maintain folio->_nr_pages_mapped anymore when (un)mapping pages, we'll account a complete folio as mapped if a single page is mapped. In addition, we'll not detect partially mapped anonymous folios as such in all cases yet. Likely less relevant changes include that we might now under-estimate the USS (Unique Set Size) of a process, but never over-estimate it. The goal is to make CONFIG_NO_PAGE_MAPCOUNT the default at some point, to then slowly make it the only option, as we learn about real-life impacts and possible ways to mitigate them. 4 Performance ============= Detailed performance numbers were included in v1 [3], and not that much changed between v1 and v2. I did plenty of measurements on different systems in the meantime, that all revealed slightly different results. The pte-mapped-folio micro-benchmarks [4] are fairly sensitive to code layout changes on some systems. Especially the fork() benchmark started being more-shaky-than-before on recent kernels for some reason. In summary, with my micro-benchmarks: * Small folios are not impacted. * CoW performance seems to be mostly unchanged across all folios sizes. * CoW reuse performance of large folios now matches CoW reuse performance of small folios, because we now actually implement the CoW reuse optimization. On an Intel Xeon Silver 4210R I measured a ~65% reduction in runtime, on an arm64 system I measured ~54% reduction. * munmap() performance improves with CONFIG_NO_PAGE_MAPCOUNT. I saw double-digit % reduction (up to ~30% on an Intel Xeon Silver 4210R and up to ~70% on an AmpereOne A192-32X) with larger folios. The larger the folios, the larger the performance improvement. * munmao() performance very slightly (couple percent) degrades without CONFIG_NO_PAGE_MAPCOUNT for smaller folios. For larger folios, there seems to be no change at all. * fork() performance improves with CONFIG_NO_PAGE_MAPCOUNT. I saw double-digit % reduction (up to ~20% on an Intel Xeon Silver 4210R and up to ~10% on an AmpereOne A192-32X) with larger folios. The larger the folios, the larger the performance improvement. * While fork() performance without CONFIG_NO_PAGE_MAPCOUNT seems to be almost unchanged on some systems, I saw some degradation for smaller folios on the AmpereOne A192-32X. I did not investigate the details yet, but I suspect code layout changes or suboptimal code placement / inlining. I'm not to worried about the fork() micro-benchmarks for smaller folios given how shaky the results are lately and by how much we improved fork() performance recently. I also ran case-anon-cow-rand and case-anon-cow-seq part of vm-scalability, to assess the scalability and the impact of the bit-spinlock. My measurements on a two 2-socket 10-core Intel Xeon Silver 4210R CPU revealed no significant changes. Similarly, running these benchmarks with 2 MiB THPs enabled on the AmpereOne A192-32X with 192 cores, I got < 1% difference with < 1% stdev, which is nice. So far, I did not get my hands on a similarly large system with multiple sockets. I found no other fitting scalability benchmarks that seem to really hammer on concurrent mapping/unmapping of large folio pages like case-anon-cow-seq does. 5 Concerns ========== 5.1 Bit spinlock ---------------- I'm not quite happy about the bit-spinlock, but so far it does not seem to affect scalability in my measurements. If it ever becomes a problem we could either investigate improving the locking, or simply stopping the MM tracking once there are "too many mappings" and simply assume that the folio is "mapped shared" until it was freed. This would be similar (but slightly different) to the "0,1,2,stopped" counting idea Willy had at some point. Adding that logic to "stop tracking" adds more code to the hot path, so I avoided that for now. 5.2 folio_maybe_mapped_shared() ------------------------------- I documented the change from folio_likely_mapped_shared() to folio_maybe_mapped_shared() quite extensively. If we run into surprises, I have some ideas on how to resolve them. For now, I think we should be fine. 5.3 Added code to map/unmap hot path ------------------------------------ So far, it looks like the added code on the rmap hot path does not really seem to matter much in the bigger picture. I'd like to further reduce it (and possibly improve fork() performance further), but I don't easily see how right now. Well, and I am out of puff 🙂 Having that said, alternatives I considered (e.g., per-MM per-folio mapcount) would add a lot more overhead to these hot paths. 6 Future Work ============= 6.1 Large mapcount ------------------ It would be very handy if the large mapcount would count how often folio pages are actually mapped into page tables: a PMD on x86-64 would count 512 times. Calculating the average per-page mapcount will be easy, and remapping (PMD->PTE) folios would get even faster. That would also remove the need for the entire mapcount (except for PMD-sized folios for memory statistics reasons ...), and allow for mapping folios larger than PMDs (e.g., 4 MiB) easily. We likely would also have to take the same number of folio references to make our folio_mapcount() == folio_ref_count() work, and we'd want to be able to avoid mapcount+refcount overflows: this could already become an issue with pte-mapped PUD-sized folios (fsdax). One approach we discussed in the THP cabal meeting is (1) extending the mapcount for large folios to 64bit (at least on 64bit systems) and (2) keeping the refcount at 32bit, but (3) having exactly one reference if the the mapcount != 0. It should be doable, but there are some corner cases to consider on the unmap path; it is something that I will be looking into next. 6.2 hugetlb ----------- I'd love to make use of the same tracking also for hugetlb. The real problem is PMD table sharing: getting a page mapped by MM X and unmapped by MM Y will not work. With mshare, that problem should not exist (all mapping/unmapping will be routed through the mshare MM). [1] https://lwn.net/Articles/974223/ [2] https://lore.kernel.org/linux-mm/a9922f58-8129-4f15-b160-e0ace581bcbe@redhat.com/T/ [3] https://lkml.kernel.org/r/20240829165627.2256514-1-david@redhat.com [4] https://gitlab.com/davidhildenbrand/scratchspace/-/raw/main/pte-mapped-folio-benchmarks.c This patch (of 20): Let's factor it out into a simple helper function. This helper will also come in handy when working with code where we know that our folio is large. Maybe in the future we'll have the order readily available for small and large folios; in that case, folio_large_order() would simply translate to folio_order(). Link: https://lkml.kernel.org/r/20250303163014.1128035-1-david@redhat.com Link: https://lkml.kernel.org/r/20250303163014.1128035-2-david@redhat.com Signed-off-by: David Hildenbrand <david@redhat.com> Reviewed-by: Lance Yang <ioworker0@gmail.com> Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Andy Lutomirks^H^Hski <luto@kernel.org> Cc: Borislav Betkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Liam Howlett <liam.howlett@oracle.com> Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Cc: Matthew Wilcow (Oracle) <willy@infradead.org> Cc: Michal Koutn <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: tejun heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Zefan Li <lizefan.x@bytedance.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Fixed overflow bug in binary search for large input.

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mutexlox closed this Sep 30, 2011

Kaz205 pushed a commit to Kaz205/linux that referenced this pull request Feb 4, 2025

Merge pull request torvalds#13 from hendecarows/feature/isdb2056

5854871

WinUSB 版 px4_drv に PX-M1UR / PX-S1UR のサポートを追加

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Fixed overflow bug in binary search for large input. #13

Fixed overflow bug in binary search for large input. #13

mutexlox commented Sep 30, 2011

Fixed overflow bug in binary search for large input. #13

Fixed overflow bug in binary search for large input. #13

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mutexlox commented Sep 30, 2011