Messages in this thread Patches in this message | | | Date | Mon, 18 Sep 2023 15:34:46 +0200 | Subject | Re: [PATCH v1 1/1] xarray: fix the data-race in xas_find_chunk() by using READ_ONCE() | From | Mirsad Todorovac <> |
| |
On 9/18/23 15:18, Jan Kara wrote: > On Mon 18-09-23 14:46:02, Mirsad Todorovac wrote: >> On 9/18/23 13:38, Jan Kara wrote: >>> On Mon 18-09-23 12:20:09, Mirsad Todorovac wrote: >>>> On 9/18/23 11:41, Jan Kara wrote: >>>>> On Mon 18-09-23 06:47:40, Mirsad Goran Todorovac wrote: >>>>>> KCSAN has discovered the following data-race: >>>>>> >>>>>> [ 206.510010] ================================================================== >>>>>> [ 206.510035] BUG: KCSAN: data-race in xas_clear_mark / xas_find_marked >>>>>> >>>>>> [ 206.510067] write to 0xffff963df6a90fe0 of 8 bytes by interrupt on cpu 22: >>>>>> [ 206.510081] xas_clear_mark (./arch/x86/include/asm/bitops.h:178 ./include/asm-generic/bitops/instrumented-non-atomic.h:115 lib/xarray.c:102 lib/xarray.c:914) >>>>>> [ 206.510097] __xa_clear_mark (lib/xarray.c:1923) >>>>>> [ 206.510114] __folio_end_writeback (mm/page-writeback.c:2981) >>>>>> [ 206.510128] folio_end_writeback (mm/filemap.c:1616) >>>>>> [ 206.510143] end_page_writeback (mm/folio-compat.c:28) >>>>>> [ 206.510155] btrfs_page_clear_writeback (fs/btrfs/subpage.c:646) btrfs >>>>>> [ 206.510994] end_bio_extent_writepage (./include/linux/bio.h:84 fs/btrfs/extent_io.c:542) btrfs >>>>>> [ 206.511817] __btrfs_bio_end_io (fs/btrfs/bio.c:117 fs/btrfs/bio.c:112) btrfs >>>>>> [ 206.512640] btrfs_orig_bbio_end_io (fs/btrfs/bio.c:164) btrfs >>>>>> [ 206.513497] btrfs_simple_end_io (fs/btrfs/bio.c:380) btrfs >>>>>> [ 206.514350] bio_endio (block/bio.c:1617) >>>>>> [ 206.514362] blk_mq_end_request_batch (block/blk-mq.c:837 block/blk-mq.c:1073) >>>>>> [ 206.514377] nvme_pci_complete_batch (drivers/nvme/host/pci.c:986) nvme >>>>>> [ 206.514437] nvme_irq (drivers/nvme/host/pci.c:1086) nvme >>>>>> [ 206.514500] __handle_irq_event_percpu (kernel/irq/handle.c:158) >>>>>> [ 206.514517] handle_irq_event (kernel/irq/handle.c:195 kernel/irq/handle.c:210) >>>>>> [ 206.514533] handle_edge_irq (kernel/irq/chip.c:836) >>>>>> [ 206.514549] __common_interrupt (./include/linux/irqdesc.h:161 arch/x86/kernel/irq.c:238 arch/x86/kernel/irq.c:257) >>>>>> [ 206.514563] common_interrupt (arch/x86/kernel/irq.c:247 (discriminator 14)) >>>>>> [ 206.514583] asm_common_interrupt (./arch/x86/include/asm/idtentry.h:636) >>>>>> [ 206.514599] kcsan_setup_watchpoint (kernel/kcsan/core.c:705 (discriminator 1)) >>>>>> [ 206.514612] __tsan_read8 (kernel/kcsan/core.c:1025) >>>>>> [ 206.514626] steal_from_bitmap.part.0 (./include/linux/find.h:186 fs/btrfs/free-space-cache.c:2557 fs/btrfs/free-space-cache.c:2613) btrfs >>>>>> [ 206.515491] __btrfs_add_free_space (fs/btrfs/free-space-cache.c:2689 fs/btrfs/free-space-cache.c:2667) btrfs >>>>>> [ 206.516361] btrfs_add_free_space_async_trimmed (fs/btrfs/free-space-cache.c:2798) btrfs >>>>>> [ 206.517231] add_new_free_space (fs/btrfs/block-group.c:550) btrfs >>>>>> [ 206.518095] load_free_space_tree (fs/btrfs/free-space-tree.c:1595 fs/btrfs/free-space-tree.c:1658) btrfs >>>>>> [ 206.518953] caching_thread (fs/btrfs/block-group.c:873) btrfs >>>>>> [ 206.519800] btrfs_work_helper (fs/btrfs/async-thread.c:314) btrfs >>>>>> [ 206.520643] process_one_work (kernel/workqueue.c:2600) >>>>>> [ 206.520658] worker_thread (./include/linux/list.h:292 kernel/workqueue.c:2752) >>>>>> [ 206.520672] kthread (kernel/kthread.c:389) >>>>>> [ 206.520684] ret_from_fork (arch/x86/kernel/process.c:145) >>>>>> [ 206.520701] ret_from_fork_asm (arch/x86/entry/entry_64.S:312) >>>>>> >>>>>> [ 206.520722] read to 0xffff963df6a90fe0 of 8 bytes by task 2793 on cpu 6: >>>>>> [ 206.520735] xas_find_marked (./include/linux/xarray.h:1706 lib/xarray.c:1354) >>>>>> [ 206.520750] filemap_get_folios_tag (mm/filemap.c:1975 mm/filemap.c:2273) >>>>>> [ 206.520763] __filemap_fdatawait_range (mm/filemap.c:519) >>>>>> [ 206.520777] filemap_fdatawait_range (mm/filemap.c:556) >>>>>> [ 206.520790] btrfs_wait_ordered_range (fs/btrfs/ordered-data.c:839) btrfs >>>>>> [ 206.521641] btrfs_sync_file (fs/btrfs/file.c:1859) btrfs >>>>>> [ 206.522495] vfs_fsync_range (fs/sync.c:188) >>>>>> [ 206.522509] __x64_sys_fsync (./include/linux/file.h:45 fs/sync.c:213 fs/sync.c:220 fs/sync.c:218 fs/sync.c:218) >>>>>> [ 206.522522] do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) >>>>>> [ 206.522535] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) >>>>>> >>>>>> [ 206.522557] value changed: 0xfffffffffff80000 -> 0xfffffffffff00000 >>>>>> >>>>>> [ 206.522574] Reported by Kernel Concurrency Sanitizer on: >>>>>> [ 206.522585] CPU: 6 PID: 2793 Comm: tracker-extract Tainted: G L 6.5.0-rc6+ #44 >>>>>> [ 206.522600] Hardware name: ASRock X670E PG Lightning/X670E PG Lightning, BIOS 1.21 04/26/2023 >>>>>> [ 206.522608] ================================================================== >>>>> >>>>> Thanks for working on this. I guess the full KCSAN warning isn't that >>>>> useful in the changelog. Rather I'd spend more time explaining the real >>>>> problem here ... >>>>> >>>>>> As Jan Kara explained, the problem is in the function xas_find_chuck(): >>>>>> >>>>>> /* Private */ >>>>>> static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance, >>>>>> xa_mark_t mark) >>>>>> { >>>>>> unsigned long *addr = xas->xa_node->marks[(__force unsigned)mark]; >>>>>> unsigned int offset = xas->xa_offset; >>>>>> >>>>>> if (advance) >>>>>> offset++; >>>>>> if (XA_CHUNK_SIZE == BITS_PER_LONG) { >>>>>> if (offset < XA_CHUNK_SIZE) { >>>>>> → unsigned long data = *addr & (~0UL << offset); >>>>>> if (data) >>>>>> return __ffs(data); >>>>> >>>>> ... which is that xas_find_chunk() is called only under RCU protection and >>>>> thus the two uses of 'data' in the above code can yield different results. >>>>> >>>>>> } >>>>>> return XA_CHUNK_SIZE; >>>>>> } >>>>>> >>>>>> return find_next_bit(addr, XA_CHUNK_SIZE, offset); >>>>>> } >>>>>> >>>>>> In particular, the line >>>>>> >>>>>> unsigned long data = *addr & (~0UL << offset); >>>>>> >>>>>> contains a data race that is best avoided using READ_ONCE(), which eliminated the KCSAN >>>>>> data-race warning completely. >>>>> >>>>> Yes, this improves the situation for xarray use on 64-bit architectures but >>>>> doesn't fix cases on 32-bit archs or if CONFIG_BASE_SMALL is set. As I >>>>> mentioned in my previous reply, I'd rather: >>>>> >>>>> 1) Fix find_next_bit(), find_first_bit() and related functions in >>>>> lib/find_bit.c to use READ_ONCE() - such as _find_first_bit() etc. It is >>>>> quite some churn but I don't see how else to make these functions safe when >>>>> the underlying contents can change. >>>> >>>> Thank you for your review. >>>> >>>> I assume you have the big picture, but just a stupid question: >>>> >>>> if (XA_CHUNK_SIZE == BITS_PER_LONG) { >>>> if (offset < XA_CHUNK_SIZE) { >>>> unsigned long data = READ_ONCE(*addr) & (~0UL << offset); >>>> if (data) >>>> return __ffs(data); >>>> } >>>> return XA_CHUNK_SIZE; >>>> } >>>> >>>> I would hate to argue, but ... >>> >>> No problem, asking questions isn't argueing ;). >>> >>>> Wouldn't BITS_PER_LONG simply change to 32 on 32-bit architectures? >>> >>> Yes, they will. But XA_CHUNK_SIZE will still be 64 on 32-bit AFAICT so >>> XA_CHUNK_SIZE != BITS_PER_LONG there. >> >> Ah, I see. This is definitely not good. But I managed to fix and test the find_next_bit() >> family, but this seems that simply >> >> ------------------------------------------- >> include/linux/xarray.h | 8 -------- >> 1 file changed, 8 deletions(-) >> >> diff --git a/include/linux/xarray.h b/include/linux/xarray.h >> index 1715fd322d62..89918b65b00d 100644 >> --- a/include/linux/xarray.h >> +++ b/include/linux/xarray.h >> @@ -1718,14 +1718,6 @@ static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance, >> if (advance) >> offset++; >> - if (XA_CHUNK_SIZE == BITS_PER_LONG) { >> - if (offset < XA_CHUNK_SIZE) { >> - unsigned long data = READ_ONCE(*addr) & (~0UL << offset); >> - if (data) >> - return __ffs(data); >> - } >> - return XA_CHUNK_SIZE; >> - } >> return find_next_bit(addr, XA_CHUNK_SIZE, offset); >> } >> >> seems too good to be true. >> >> According to what you explained, the performance impact would be negligent or non-existing, >> and the CONFIG_BASE_SMALL problem would disappear? > > If you fix find_next_bit(), then this will fix xas_find_chunk(), yes.
Just testing that.
>> I did not even try to run that, as I am not 100% confident in the logic. >> >> Am I doing something very wrong? > > No, this is exactly what I think needs to happen.
Great then, I will apply this fix and try a test run. Of course, under your supervision ...
>>>> Is there something I am missing? >>>> >>>> From include/asm-generic/bitsperlong.h: >>>> ---------------------------------------- >>>> #ifdef CONFIG_64BIT >>>> #define BITS_PER_LONG 64 >>>> #else >>>> #define BITS_PER_LONG 32 >>>> #endif /* CONFIG_64BIT */ >>>> >>>> About the CONFIG_BASE_SMALL I cannot tell: >>>> ---------------------------------------- >>>> #ifndef XA_CHUNK_SHIFT >>>> #define XA_CHUNK_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) >>>> #endif >>>> #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT) >>>> #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1) >>>> #define XA_MAX_MARKS 3 >>>> #define XA_MARK_LONGS DIV_ROUND_UP(XA_CHUNK_SIZE, BITS_PER_LONG) >>>> ---------------------------------------- >>> >>> Again with CONFIG_BASE_SMALL we have XA_CHUNK_SIZE == 16 so it will not be >>> equal to BITS_PER_LONG. >>>> I see why you would want find_next_bit() and find_first_bit() fixed, but >>>> I am not that deep into those bitops, so I guess I cannot make this in >>>> one step ... Probably it would require a lot of homework. >>>> >>>> _find_*_bit() functions and/or macros cause quite a number of KCSAN BUG warnings: >>>> >>>> 95 _find_first_and_bit (lib/find_bit.c:114 (discriminator 10)) >>>> 31 _find_first_zero_bit (lib/find_bit.c:125 (discriminator 10)) >>>> 173 _find_next_and_bit (lib/find_bit.c:171 (discriminator 2)) >>>> 655 _find_next_bit (lib/find_bit.c:133 (discriminator 2)) >>>> 5 _find_next_zero_bit >>>> >>>> ... but I am simply not certain what is the right thing to do ATM about >>>> those and whether they are false positives. >>> >>> Well, it would require some auditing to be sure but there is at least one >>> user of these functions (xarray) where the problem is real so given the fix >>> has no real runtime cost the fix looks justified. >>> >>>> AFAICS, READ_ONCE() here solves the case of 64 and 32 architectures which is >>>> an incremental step, and it works ... I am just not ready for an >>>> universal solution ATM. >>>> >>>>> 2) Change xas_find_chunk() to unconditionally use find_next_bit() as the >>>>> special case XA_CHUNK_SIZE == BITS_PER_LONG seems pointless these days >>>>> because find_next_bit() is inline and does small_const_nbits(size) check. >>>> >>>> I see your point. A generalised solution would of course be better. But >>>> from the report about data-races in those functions it seems that they >>>> need a major rethink. It isn't that obvious to me what should be >>>> READ_ONCE()-ed in a bit field ... >>> >>> Well, it's actually not that difficult. They all need a treatment like: >>> >>> unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, uns >>> { >>> - return FIND_NEXT_BIT(addr[idx], /* nop */, nbits, start); >>> + return FIND_NEXT_BIT(READ_ONCE(addr[idx]), /* nop */, nbits, start); >>> } >>> >>> >>>> Those functions are extensively used throughout the kernel and I get the >>>> notion it is a job for someone with more experience ... >>> >>> Sure, if you don't feel like doing the general change, I can look into it >>> myself. >>> >>> Honza >> >> Hi, >> >> I tried this patch and the >> >>>> 95 _find_first_and_bit (lib/find_bit.c:114 (discriminator 10)) >>>> 31 _find_first_zero_bit (lib/find_bit.c:125 (discriminator 10)) >>>> 173 _find_next_and_bit (lib/find_bit.c:171 (discriminator 2)) >>>> 655 _find_next_bit (lib/find_bit.c:133 (discriminator 2)) >>>> 5 _find_next_zero_bit >> >> data-races do not seem to appear any longer. > > Yup. You've just missed one case in _find_last_bit() and then all the > functions in include/linux/find.h need a similar treatment...
I seem to have this:
----------------------------------------------------------------------------------- #ifndef find_last_bit unsigned long _find_last_bit(const unsigned long *addr, unsigned long size) { if (size) { unsigned long val = BITMAP_LAST_WORD_MASK(size); unsigned long idx = (size-1) / BITS_PER_LONG;
do { val &= READ_ONCE(addr[idx]); if (val) return idx * BITS_PER_LONG + __fls(val);
val = ~0ul; } while (idx--); } return size; } EXPORT_SYMBOL(_find_last_bit); #endif -----------------------------------------------------------------------------------
Is there something I did not notice?
Just in case, I am adding the find_bit.diff because copy/paste might have been wrong ...
Mirsad
> > Honza > >> >> -------------------------------------------------------- >> lib/find_bit.c | 33 +++++++++++++++++---------------- >> 1 file changed, 17 insertions(+), 16 deletions(-) >> >> diff --git a/lib/find_bit.c b/lib/find_bit.c >> index 32f99e9a670e..56244e4f744e 100644 >> --- a/lib/find_bit.c >> +++ b/lib/find_bit.c >> @@ -18,6 +18,7 @@ >> #include <linux/math.h> >> #include <linux/minmax.h> >> #include <linux/swab.h> >> +#include <asm/rwonce.h> >> /* >> * Common helper for find_bit() function family >> @@ -98,7 +99,7 @@ out: \ >> */ >> unsigned long _find_first_bit(const unsigned long *addr, unsigned long size) >> { >> - return FIND_FIRST_BIT(addr[idx], /* nop */, size); >> + return FIND_FIRST_BIT(READ_ONCE(addr[idx]), /* nop */, size); >> } >> EXPORT_SYMBOL(_find_first_bit); >> #endif >> @@ -111,7 +112,7 @@ unsigned long _find_first_and_bit(const unsigned long *addr1, >> const unsigned long *addr2, >> unsigned long size) >> { >> - return FIND_FIRST_BIT(addr1[idx] & addr2[idx], /* nop */, size); >> + return FIND_FIRST_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]), /* nop */, size); >> } >> EXPORT_SYMBOL(_find_first_and_bit); >> #endif >> @@ -122,7 +123,7 @@ EXPORT_SYMBOL(_find_first_and_bit); >> */ >> unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size) >> { >> - return FIND_FIRST_BIT(~addr[idx], /* nop */, size); >> + return FIND_FIRST_BIT(~READ_ONCE(addr[idx]), /* nop */, size); >> } >> EXPORT_SYMBOL(_find_first_zero_bit); >> #endif >> @@ -130,28 +131,28 @@ EXPORT_SYMBOL(_find_first_zero_bit); >> #ifndef find_next_bit >> unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, unsigned long start) >> { >> - return FIND_NEXT_BIT(addr[idx], /* nop */, nbits, start); >> + return FIND_NEXT_BIT(READ_ONCE(addr[idx]), /* nop */, nbits, start); >> } >> EXPORT_SYMBOL(_find_next_bit); >> #endif >> unsigned long __find_nth_bit(const unsigned long *addr, unsigned long size, unsigned long n) >> { >> - return FIND_NTH_BIT(addr[idx], size, n); >> + return FIND_NTH_BIT(READ_ONCE(addr[idx]), size, n); >> } >> EXPORT_SYMBOL(__find_nth_bit); >> unsigned long __find_nth_and_bit(const unsigned long *addr1, const unsigned long *addr2, >> unsigned long size, unsigned long n) >> { >> - return FIND_NTH_BIT(addr1[idx] & addr2[idx], size, n); >> + return FIND_NTH_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]), size, n); >> } >> EXPORT_SYMBOL(__find_nth_and_bit); >> unsigned long __find_nth_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, >> unsigned long size, unsigned long n) >> { >> - return FIND_NTH_BIT(addr1[idx] & ~addr2[idx], size, n); >> + return FIND_NTH_BIT(READ_ONCE(addr1[idx]) & ~READ_ONCE(addr2[idx]), size, n); >> } >> EXPORT_SYMBOL(__find_nth_andnot_bit); >> @@ -160,7 +161,7 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, >> const unsigned long *addr3, >> unsigned long size, unsigned long n) >> { >> - return FIND_NTH_BIT(addr1[idx] & addr2[idx] & ~addr3[idx], size, n); >> + return FIND_NTH_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]) & ~READ_ONCE(addr3[idx]), size, n); >> } >> EXPORT_SYMBOL(__find_nth_and_andnot_bit); >> @@ -168,7 +169,7 @@ EXPORT_SYMBOL(__find_nth_and_andnot_bit); >> unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2, >> unsigned long nbits, unsigned long start) >> { >> - return FIND_NEXT_BIT(addr1[idx] & addr2[idx], /* nop */, nbits, start); >> + return FIND_NEXT_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]), /* nop */, nbits, start); >> } >> EXPORT_SYMBOL(_find_next_and_bit); >> #endif >> @@ -177,7 +178,7 @@ EXPORT_SYMBOL(_find_next_and_bit); >> unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, >> unsigned long nbits, unsigned long start) >> { >> - return FIND_NEXT_BIT(addr1[idx] & ~addr2[idx], /* nop */, nbits, start); >> + return FIND_NEXT_BIT(READ_ONCE(addr1[idx]) & ~READ_ONCE(addr2[idx]), /* nop */, nbits, start); >> } >> EXPORT_SYMBOL(_find_next_andnot_bit); >> #endif >> @@ -186,7 +187,7 @@ EXPORT_SYMBOL(_find_next_andnot_bit); >> unsigned long _find_next_or_bit(const unsigned long *addr1, const unsigned long *addr2, >> unsigned long nbits, unsigned long start) >> { >> - return FIND_NEXT_BIT(addr1[idx] | addr2[idx], /* nop */, nbits, start); >> + return FIND_NEXT_BIT(READ_ONCE(addr1[idx]) | READ_ONCE(addr2[idx]), /* nop */, nbits, start); >> } >> EXPORT_SYMBOL(_find_next_or_bit); >> #endif >> @@ -195,7 +196,7 @@ EXPORT_SYMBOL(_find_next_or_bit); >> unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits, >> unsigned long start) >> { >> - return FIND_NEXT_BIT(~addr[idx], /* nop */, nbits, start); >> + return FIND_NEXT_BIT(~READ_ONCE(addr[idx]), /* nop */, nbits, start); >> } >> EXPORT_SYMBOL(_find_next_zero_bit); >> #endif >> @@ -208,7 +209,7 @@ unsigned long _find_last_bit(const unsigned long *addr, unsigned long size) >> unsigned long idx = (size-1) / BITS_PER_LONG; >> do { >> - val &= addr[idx]; >> + val &= READ_ONCE(addr[idx]); >> if (val) >> return idx * BITS_PER_LONG + __fls(val); >> @@ -242,7 +243,7 @@ EXPORT_SYMBOL(find_next_clump8); >> */ >> unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size) >> { >> - return FIND_FIRST_BIT(~addr[idx], swab, size); >> + return FIND_FIRST_BIT(~READ_ONCE(addr[idx]), swab, size); >> } >> EXPORT_SYMBOL(_find_first_zero_bit_le); >> @@ -252,7 +253,7 @@ EXPORT_SYMBOL(_find_first_zero_bit_le); >> unsigned long _find_next_zero_bit_le(const unsigned long *addr, >> unsigned long size, unsigned long offset) >> { >> - return FIND_NEXT_BIT(~addr[idx], swab, size, offset); >> + return FIND_NEXT_BIT(~READ_ONCE(addr[idx]), swab, size, offset); >> } >> EXPORT_SYMBOL(_find_next_zero_bit_le); >> #endif >> @@ -261,7 +262,7 @@ EXPORT_SYMBOL(_find_next_zero_bit_le); >> unsigned long _find_next_bit_le(const unsigned long *addr, >> unsigned long size, unsigned long offset) >> { >> - return FIND_NEXT_BIT(addr[idx], swab, size, offset); >> + return FIND_NEXT_BIT(READ_ONCE(addr[idx]), swab, size, offset); >> } >> EXPORT_SYMBOL(_find_next_bit_le); >> --diff --git a/lib/find_bit.c b/lib/find_bit.c index 32f99e9a670e..56244e4f744e 100644 --- a/lib/find_bit.c +++ b/lib/find_bit.c @@ -18,6 +18,7 @@ #include <linux/math.h> #include <linux/minmax.h> #include <linux/swab.h> +#include <asm/rwonce.h> /* * Common helper for find_bit() function family @@ -98,7 +99,7 @@ out: \ */ unsigned long _find_first_bit(const unsigned long *addr, unsigned long size) { - return FIND_FIRST_BIT(addr[idx], /* nop */, size); + return FIND_FIRST_BIT(READ_ONCE(addr[idx]), /* nop */, size); } EXPORT_SYMBOL(_find_first_bit); #endif @@ -111,7 +112,7 @@ unsigned long _find_first_and_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long size) { - return FIND_FIRST_BIT(addr1[idx] & addr2[idx], /* nop */, size); + return FIND_FIRST_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]), /* nop */, size); } EXPORT_SYMBOL(_find_first_and_bit); #endif @@ -122,7 +123,7 @@ EXPORT_SYMBOL(_find_first_and_bit); */ unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long size) { - return FIND_FIRST_BIT(~addr[idx], /* nop */, size); + return FIND_FIRST_BIT(~READ_ONCE(addr[idx]), /* nop */, size); } EXPORT_SYMBOL(_find_first_zero_bit); #endif @@ -130,28 +131,28 @@ EXPORT_SYMBOL(_find_first_zero_bit); #ifndef find_next_bit unsigned long _find_next_bit(const unsigned long *addr, unsigned long nbits, unsigned long start) { - return FIND_NEXT_BIT(addr[idx], /* nop */, nbits, start); + return FIND_NEXT_BIT(READ_ONCE(addr[idx]), /* nop */, nbits, start); } EXPORT_SYMBOL(_find_next_bit); #endif unsigned long __find_nth_bit(const unsigned long *addr, unsigned long size, unsigned long n) { - return FIND_NTH_BIT(addr[idx], size, n); + return FIND_NTH_BIT(READ_ONCE(addr[idx]), size, n); } EXPORT_SYMBOL(__find_nth_bit); unsigned long __find_nth_and_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long size, unsigned long n) { - return FIND_NTH_BIT(addr1[idx] & addr2[idx], size, n); + return FIND_NTH_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]), size, n); } EXPORT_SYMBOL(__find_nth_and_bit); unsigned long __find_nth_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long size, unsigned long n) { - return FIND_NTH_BIT(addr1[idx] & ~addr2[idx], size, n); + return FIND_NTH_BIT(READ_ONCE(addr1[idx]) & ~READ_ONCE(addr2[idx]), size, n); } EXPORT_SYMBOL(__find_nth_andnot_bit); @@ -160,7 +161,7 @@ unsigned long __find_nth_and_andnot_bit(const unsigned long *addr1, const unsigned long *addr3, unsigned long size, unsigned long n) { - return FIND_NTH_BIT(addr1[idx] & addr2[idx] & ~addr3[idx], size, n); + return FIND_NTH_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]) & ~READ_ONCE(addr3[idx]), size, n); } EXPORT_SYMBOL(__find_nth_and_andnot_bit); @@ -168,7 +169,7 @@ EXPORT_SYMBOL(__find_nth_and_andnot_bit); unsigned long _find_next_and_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long nbits, unsigned long start) { - return FIND_NEXT_BIT(addr1[idx] & addr2[idx], /* nop */, nbits, start); + return FIND_NEXT_BIT(READ_ONCE(addr1[idx]) & READ_ONCE(addr2[idx]), /* nop */, nbits, start); } EXPORT_SYMBOL(_find_next_and_bit); #endif @@ -177,7 +178,7 @@ EXPORT_SYMBOL(_find_next_and_bit); unsigned long _find_next_andnot_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long nbits, unsigned long start) { - return FIND_NEXT_BIT(addr1[idx] & ~addr2[idx], /* nop */, nbits, start); + return FIND_NEXT_BIT(READ_ONCE(addr1[idx]) & ~READ_ONCE(addr2[idx]), /* nop */, nbits, start); } EXPORT_SYMBOL(_find_next_andnot_bit); #endif @@ -186,7 +187,7 @@ EXPORT_SYMBOL(_find_next_andnot_bit); unsigned long _find_next_or_bit(const unsigned long *addr1, const unsigned long *addr2, unsigned long nbits, unsigned long start) { - return FIND_NEXT_BIT(addr1[idx] | addr2[idx], /* nop */, nbits, start); + return FIND_NEXT_BIT(READ_ONCE(addr1[idx]) | READ_ONCE(addr2[idx]), /* nop */, nbits, start); } EXPORT_SYMBOL(_find_next_or_bit); #endif @@ -195,7 +196,7 @@ EXPORT_SYMBOL(_find_next_or_bit); unsigned long _find_next_zero_bit(const unsigned long *addr, unsigned long nbits, unsigned long start) { - return FIND_NEXT_BIT(~addr[idx], /* nop */, nbits, start); + return FIND_NEXT_BIT(~READ_ONCE(addr[idx]), /* nop */, nbits, start); } EXPORT_SYMBOL(_find_next_zero_bit); #endif @@ -208,7 +209,7 @@ unsigned long _find_last_bit(const unsigned long *addr, unsigned long size) unsigned long idx = (size-1) / BITS_PER_LONG; do { - val &= addr[idx]; + val &= READ_ONCE(addr[idx]); if (val) return idx * BITS_PER_LONG + __fls(val); @@ -242,7 +243,7 @@ EXPORT_SYMBOL(find_next_clump8); */ unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size) { - return FIND_FIRST_BIT(~addr[idx], swab, size); + return FIND_FIRST_BIT(~READ_ONCE(addr[idx]), swab, size); } EXPORT_SYMBOL(_find_first_zero_bit_le); @@ -252,7 +253,7 @@ EXPORT_SYMBOL(_find_first_zero_bit_le); unsigned long _find_next_zero_bit_le(const unsigned long *addr, unsigned long size, unsigned long offset) { - return FIND_NEXT_BIT(~addr[idx], swab, size, offset); + return FIND_NEXT_BIT(~READ_ONCE(addr[idx]), swab, size, offset); } EXPORT_SYMBOL(_find_next_zero_bit_le); #endif @@ -261,7 +262,7 @@ EXPORT_SYMBOL(_find_next_zero_bit_le); unsigned long _find_next_bit_le(const unsigned long *addr, unsigned long size, unsigned long offset) { - return FIND_NEXT_BIT(addr[idx], swab, size, offset); + return FIND_NEXT_BIT(READ_ONCE(addr[idx]), swab, size, offset); } EXPORT_SYMBOL(_find_next_bit_le); | |