kernel/linux.git/drivers/isdn/mISDN/timerdev.c, branch linux-4.4.y

mISDN: fix a race in dev_expire_timer()

2019-02-23T08:05:14+00:00

commit bdcc5bc25548ef6b08e2e43937148f907c212292 upstream. Since mISDN_close() uses dev->pending to iterate over active timers, there is a chance that one timer got removed from the ->pending list in dev_expire_timer() but that the thread has not called yet wake_up_interruptible() So mISDN_close() could miss this and free dev before completion of at least one dev_expire_timer() syzbot was able to catch this race : BUG: KASAN: use-after-free in register_lock_class+0x140c/0x1bf0 kernel/locking/lockdep.c:827 Write of size 8 at addr ffff88809fc18948 by task syz-executor1/24769 CPU: 1 PID: 24769 Comm: syz-executor1 Not tainted 5.0.0-rc5 #60 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 __asan_report_store8_noabort+0x17/0x20 mm/kasan/generic_report.c:140 register_lock_class+0x140c/0x1bf0 kernel/locking/lockdep.c:827 __lock_acquire+0x11f/0x4700 kernel/locking/lockdep.c:3224 lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:3841 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 __wake_up_common_lock+0xc7/0x190 kernel/sched/wait.c:120 __wake_up+0xe/0x10 kernel/sched/wait.c:145 dev_expire_timer+0xe4/0x3b0 drivers/isdn/mISDN/timerdev.c:174 call_timer_fn+0x190/0x720 kernel/time/timer.c:1325 protocol 88fb is buggy, dev hsr_slave_0 protocol 88fb is buggy, dev hsr_slave_1 expire_timers kernel/time/timer.c:1362 [inline] __run_timers kernel/time/timer.c:1681 [inline] __run_timers kernel/time/timer.c:1649 [inline] run_timer_softirq+0x652/0x1700 kernel/time/timer.c:1694 __do_softirq+0x266/0x95a kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x180/0x1d0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0x14a/0x570 arch/x86/kernel/apic/apic.c:1062 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:807 RIP: 0010:__sanitizer_cov_trace_pc+0x26/0x50 kernel/kcov.c:101 Code: 90 90 90 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 40 ee 01 00 65 8b 15 98 12 92 7e 81 e2 00 01 1f 00 75 2b 8b 90 d8 12 00 00 <83> fa 02 75 20 48 8b 88 e0 12 00 00 8b 80 dc 12 00 00 48 8b 11 48 RSP: 0018:ffff8880589b7a60 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 RAX: ffff888087ce25c0 RBX: 0000000000000001 RCX: ffffffff818f8ca3 RDX: 0000000000000000 RSI: ffffffff818f8b48 RDI: 0000000000000001 RBP: ffff8880589b7a60 R08: ffff888087ce25c0 R09: ffffed1015d25bd0 R10: ffffed1015d25bcf R11: ffff8880ae92de7b R12: ffffea0001ae4680 R13: ffffea0001ae4688 R14: 0000000000000000 R15: ffffea0001b41648 PageIdle include/linux/page-flags.h:398 [inline] page_is_idle include/linux/page_idle.h:29 [inline] mark_page_accessed+0x618/0x1140 mm/swap.c:398 touch_buffer fs/buffer.c:59 [inline] __find_get_block+0x312/0xcc0 fs/buffer.c:1298 sb_find_get_block include/linux/buffer_head.h:338 [inline] recently_deleted fs/ext4/ialloc.c:682 [inline] find_inode_bit.isra.0+0x202/0x510 fs/ext4/ialloc.c:722 __ext4_new_inode+0x14ad/0x52c0 fs/ext4/ialloc.c:914 ext4_symlink+0x3f8/0xbe0 fs/ext4/namei.c:3096 vfs_symlink fs/namei.c:4126 [inline] vfs_symlink+0x378/0x5d0 fs/namei.c:4112 do_symlinkat+0x22b/0x290 fs/namei.c:4153 __do_sys_symlink fs/namei.c:4172 [inline] __se_sys_symlink fs/namei.c:4170 [inline] __x64_sys_symlink+0x59/0x80 fs/namei.c:4170 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457b67 Code: 0f 1f 00 b8 5c 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 6d bb fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 58 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 4d bb fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fff045ce0f8 EFLAGS: 00000202 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457b67 RDX: 00007fff045ce173 RSI: 00000000004bd63f RDI: 00007fff045ce160 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000013 R10: 0000000000000075 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000001 R14: 000000000000029b R15: 0000000000000001 Allocated by task 24763: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc mm/kasan/common.c:496 [inline] __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:469 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:504 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3609 kmalloc include/linux/slab.h:545 [inline] mISDN_open+0x9a/0x270 drivers/isdn/mISDN/timerdev.c:59 misc_open+0x398/0x4c0 drivers/char/misc.c:141 chrdev_open+0x247/0x6b0 fs/char_dev.c:417 do_dentry_open+0x47d/0x1130 fs/open.c:771 vfs_open+0xa0/0xd0 fs/open.c:880 do_last fs/namei.c:3418 [inline] path_openat+0x10d7/0x4690 fs/namei.c:3534 do_filp_open+0x1a1/0x280 fs/namei.c:3564 do_sys_open+0x3fe/0x5d0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Freed by task 24762: save_stack+0x45/0xd0 mm/kasan/common.c:73 set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x102/0x150 mm/kasan/common.c:458 kasan_slab_free+0xe/0x10 mm/kasan/common.c:466 __cache_free mm/slab.c:3487 [inline] kfree+0xcf/0x230 mm/slab.c:3806 mISDN_close+0x2a1/0x390 drivers/isdn/mISDN/timerdev.c:97 __fput+0x2df/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe The buggy address belongs to the object at ffff88809fc18900 which belongs to the cache kmalloc-192 of size 192 The buggy address is located 72 bytes inside of 192-byte region [ffff88809fc18900, ffff88809fc189c0) The buggy address belongs to the page: page:ffffea00027f0600 count:1 mapcount:0 mapping:ffff88812c3f0040 index:0xffff88809fc18000 flags: 0x1fffc0000000200(slab) raw: 01fffc0000000200 ffffea000269f648 ffffea00029f7408 ffff88812c3f0040 raw: ffff88809fc18000 ffff88809fc18000 000000010000000b 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88809fc18800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffff88809fc18880: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff88809fc18900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88809fc18980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc ffff88809fc18a00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Signed-off-by: Eric Dumazet Cc: Karsten Keil Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

mISDN: grabbing/dropping reference to THIS_MODULE in open/release is racy

2013-04-29T19:41:49+00:00

... when you have no ->owner set. Signed-off-by: Al Viro

mISDN: fix mISDN_read()/mISDN_read() race

2013-04-29T19:41:49+00:00

Signed-off-by: Al Viro

mISDN: fix misdn_add_timer()/misdn_del_timer() race

2013-04-29T19:41:48+00:00

do add_timer() *before* unlocking dev->lock, or unpleasant things can happen if misdn_del_timer() on another CPU finds the sucker, calls del_timer_sync() (which does nothing, since we hadn't started the timer yet) and frees it, just as we get around to add_timer()... Signed-off-by: Al Viro

mISDN: fix races between misdn_del_timer() and timer callback

2013-04-29T19:41:48+00:00

mark the victim with negative ->id if misdn_del_timer() finds it on the list, have timer callback *not* move ones so marked to dev->expired Signed-off-by: Al Viro

mISDN: fix the races with timers going off just as they are deleted

2013-04-29T19:41:47+00:00

timer callback in timerdev.c both accesses struct mISDNtimer it's called for *and* moves it to dev->expired. We need del_timer_sync(), or we risk kfree() freeing it right under dev_expire_timer() *and* dev->expired getting corrupted. Signed-off-by: Al Viro

isdn: whitespace coding style cleanup

2012-02-21T17:04:01+00:00

isdn source code uses a not-current coding style. Update the coding style used on a per-line basis so that git diff -w shows only elided blank lines at EOF. Done with emacs and some scripts and some typing. Built x86 allyesconfig. No detected change in objdump -d or size. Signed-off-by: Joe Perches

llseek: automatically add .llseek fop

2010-10-15T13:53:27+00:00

All file_operations should get a .llseek operation so we can make nonseekable_open the default for future file operations without a .llseek pointer. The three cases that we can automatically detect are no_llseek, seq_lseek and default_llseek. For cases where we can we can automatically prove that the file offset is always ignored, we use noop_llseek, which maintains the current behavior of not returning an error from a seek. New drivers should normally not use noop_llseek but instead use no_llseek and call nonseekable_open at open time. Existing drivers can be converted to do the same when the maintainer knows for certain that no user code relies on calling seek on the device file. The generated code is often incorrectly indented and right now contains comments that clarify for each added line why a specific variant was chosen. In the version that gets submitted upstream, the comments will be gone and I will manually fix the indentation, because there does not seem to be a way to do that using coccinelle. Some amount of new code is currently sitting in linux-next that should get the same modifications, which I will do at the end of the merge window. Many thanks to Julia Lawall for helping me learn to write a semantic patch that does all this. ===== begin semantic patch ===== // This adds an llseek= method to all file operations, // as a preparation for making no_llseek the default. // // The rules are // - use no_llseek explicitly if we do nonseekable_open // - use seq_lseek for sequential files // - use default_llseek if we know we access f_pos // - use noop_llseek if we know we don't access f_pos, // but we still want to allow users to call lseek // @ open1 exists @ identifier nested_open; @@ nested_open(...) { <+... nonseekable_open(...) ...+> } @ open exists@ identifier open_f; identifier i, f; identifier open1.nested_open; @@ int open_f(struct inode *i, struct file *f) { <+... ( nonseekable_open(...) | nested_open(...) ) ...+> } @ read disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ read_no_fpos disable optional_qualifier exists @ identifier read_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off) { ... when != off } @ write @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; expression E; identifier func; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { <+... ( *off = E | *off += E | func(..., off, ...) | E = *off ) ...+> } @ write_no_fpos @ identifier write_f; identifier f, p, s, off; type ssize_t, size_t, loff_t; @@ ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off) { ... when != off } @ fops0 @ identifier fops; @@ struct file_operations fops = { ... }; @ has_llseek depends on fops0 @ identifier fops0.fops; identifier llseek_f; @@ struct file_operations fops = { ... .llseek = llseek_f, ... }; @ has_read depends on fops0 @ identifier fops0.fops; identifier read_f; @@ struct file_operations fops = { ... .read = read_f, ... }; @ has_write depends on fops0 @ identifier fops0.fops; identifier write_f; @@ struct file_operations fops = { ... .write = write_f, ... }; @ has_open depends on fops0 @ identifier fops0.fops; identifier open_f; @@ struct file_operations fops = { ... .open = open_f, ... }; // use no_llseek if we call nonseekable_open //////////////////////////////////////////// @ nonseekable1 depends on !has_llseek && has_open @ identifier fops0.fops; identifier nso ~= "nonseekable_open"; @@ struct file_operations fops = { ... .open = nso, ... +.llseek = no_llseek, /* nonseekable */ }; @ nonseekable2 depends on !has_llseek @ identifier fops0.fops; identifier open.open_f; @@ struct file_operations fops = { ... .open = open_f, ... +.llseek = no_llseek, /* open uses nonseekable */ }; // use seq_lseek for sequential files ///////////////////////////////////// @ seq depends on !has_llseek @ identifier fops0.fops; identifier sr ~= "seq_read"; @@ struct file_operations fops = { ... .read = sr, ... +.llseek = seq_lseek, /* we have seq_read */ }; // use default_llseek if there is a readdir /////////////////////////////////////////// @ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier readdir_e; @@ // any other fop is used that changes pos struct file_operations fops = { ... .readdir = readdir_e, ... +.llseek = default_llseek, /* readdir is present */ }; // use default_llseek if at least one of read/write touches f_pos ///////////////////////////////////////////////////////////////// @ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read.read_f; @@ // read fops use offset struct file_operations fops = { ... .read = read_f, ... +.llseek = default_llseek, /* read accesses f_pos */ }; @ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, ... + .llseek = default_llseek, /* write accesses f_pos */ }; // Use noop_llseek if neither read nor write accesses f_pos /////////////////////////////////////////////////////////// @ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; identifier write_no_fpos.write_f; @@ // write fops use offset struct file_operations fops = { ... .write = write_f, .read = read_f, ... +.llseek = noop_llseek, /* read and write both use no f_pos */ }; @ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier write_no_fpos.write_f; @@ struct file_operations fops = { ... .write = write_f, ... +.llseek = noop_llseek, /* write uses no f_pos */ }; @ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; identifier read_no_fpos.read_f; @@ struct file_operations fops = { ... .read = read_f, ... +.llseek = noop_llseek, /* read uses no f_pos */ }; @ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @ identifier fops0.fops; @@ struct file_operations fops = { ... +.llseek = noop_llseek, /* no read or write fn */ }; ===== End semantic patch ===== Signed-off-by: Arnd Bergmann Cc: Julia Lawall Cc: Christoph Hellwig

isdn: autoconvert trivial BKL users to private mutex

2010-07-13T03:21:47+00:00

All these files use the big kernel lock in a trivial way to serialize their private file operations, typically resulting from an earlier semi-automatic pushdown from VFS. None of these drivers appears to want to lock against other code, and they all use the BKL as the top-level lock in their file operations, meaning that there is no lock-order inversion problem. Consequently, we can remove the BKL completely, replacing it with a per-file mutex in every case. Using a scripted approach means we can avoid typos. file=$1 name=$2 if grep -q lock_kernel ${file} ; then if grep -q 'include.*linux.mutex.h' ${file} ; then sed -i '/include.*/d' ${file} else sed -i 's/include.*.*$/include /g' ${file} fi sed -i ${file} \ -e "/^#include.*linux.mutex.h/,$ { 1,/^$static\|int\|long$/ { /^$static\|int\|long$/istatic DEFINE_MUTEX(${name}_mutex); } }" \ -e "s/$un$*lock_kernel\>[ ]*()/mutex_\1lock(\&${name}_mutex)/g" \ -e '/[ ]*cycle_kernel_lock();/d' else sed -i -e '/include.*\/d' ${file} \ -e '/cycle_kernel_lock()/d' fi Signed-off-by: Arnd Bergmann Cc: Karsten Keil Cc: netdev@vger.kernel.org Signed-off-by: David S. Miller

mISDN: remove unnecessary test on f_pos

2010-05-27T16:12:56+00:00

This test is not doing anything since it is always false if the mISDN_read() is called from vfs_read(). Besides that the driver uses nonseekable_open() and is not using off or file->f_pos anywhere. Signed-off-by: Jan Blunck Cc: Frederic Weisbecker Cc: Karsten Keil Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds