| Message ID | 20190108183041.GA12137@jordon-HP-15-Notebook-PC (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4] mm: Create the new vm_fault_t type | expand |
On Wed, Jan 09, 2019 at 12:00:41AM +0530, Souptick Joarder wrote: > Page fault handlers are supposed to return VM_FAULT codes, > but some drivers/file systems mistakenly return error > numbers. Now that all drivers/file systems have been converted > to use the vm_fault_t return type, change the type definition > to no longer be compatible with 'int'. By making it an unsigned > int, the function prototype becomes incompatible with a function > which returns int. Sparse will detect any attempts to return a > value which is not a VM_FAULT code. > > VM_FAULT_SET_HINDEX and VM_FAULT_GET_HINDEX values are changed > to avoid conflict with other VM_FAULT codes. > > Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com> > Reviewed-by: William Kucharski <william.kucharski@oracle.com> > Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Matthew Wilcox <willy@infradead.org>
Hi Souptick,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v5.0-rc1 next-20190109]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Souptick-Joarder/mm-Create-the-new-vm_fault_t-type/20190109-154216
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All warnings (new ones prefixed by >>):
>> arch/x86/mm/fault.c:1051:39: warning: restricted vm_fault_t degrades to integer
arch/x86/mm/fault.c:1057:29: warning: restricted vm_fault_t degrades to integer
arch/x86/mm/fault.c:1059:29: warning: restricted vm_fault_t degrades to integer
>> arch/x86/mm/fault.c:1094:62: warning: incorrect type in argument 4 (different base types)
arch/x86/mm/fault.c:1094:62: expected unsigned int fault
arch/x86/mm/fault.c:1094:62: got restricted vm_fault_t [usertype] fault
vim +1051 arch/x86/mm/fault.c
92181f190 Nick Piggin 2009-01-20 1031
2d4a71676 Ingo Molnar 2009-02-20 1032 static void
a6e04aa92 Andi Kleen 2009-09-16 1033 do_sigbus(struct pt_regs *regs, unsigned long error_code, unsigned long address,
27274f731 Eric W. Biederman 2018-09-18 1034 unsigned int fault)
92181f190 Nick Piggin 2009-01-20 1035 {
92181f190 Nick Piggin 2009-01-20 1036 struct task_struct *tsk = current;
92181f190 Nick Piggin 2009-01-20 1037
2d4a71676 Ingo Molnar 2009-02-20 1038 /* Kernel mode? Handle exceptions or die: */
1067f0309 Ricardo Neri 2017-10-27 1039 if (!(error_code & X86_PF_USER)) {
4fc349011 Andy Lutomirski 2011-11-07 1040 no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
960545691 Linus Torvalds 2010-08-13 1041 return;
960545691 Linus Torvalds 2010-08-13 1042 }
2d4a71676 Ingo Molnar 2009-02-20 1043
cd1b68f08 Ingo Molnar 2009-02-20 1044 /* User-space => ok to do another page fault: */
92181f190 Nick Piggin 2009-01-20 1045 if (is_prefetch(regs, error_code, address))
92181f190 Nick Piggin 2009-01-20 1046 return;
2d4a71676 Ingo Molnar 2009-02-20 1047
e49d3cbef Andy Lutomirski 2018-11-19 1048 set_signal_archinfo(address, error_code);
2d4a71676 Ingo Molnar 2009-02-20 1049
a6e04aa92 Andi Kleen 2009-09-16 1050 #ifdef CONFIG_MEMORY_FAILURE
f672b49b0 Andi Kleen 2010-09-27 @1051 if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
40e553946 Eric W. Biederman 2018-01-19 1052 unsigned lsb = 0;
40e553946 Eric W. Biederman 2018-01-19 1053
40e553946 Eric W. Biederman 2018-01-19 1054 pr_err(
a6e04aa92 Andi Kleen 2009-09-16 1055 "MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
a6e04aa92 Andi Kleen 2009-09-16 1056 tsk->comm, tsk->pid, address);
40e553946 Eric W. Biederman 2018-01-19 1057 if (fault & VM_FAULT_HWPOISON_LARGE)
40e553946 Eric W. Biederman 2018-01-19 1058 lsb = hstate_index_to_shift(VM_FAULT_GET_HINDEX(fault));
40e553946 Eric W. Biederman 2018-01-19 1059 if (fault & VM_FAULT_HWPOISON)
40e553946 Eric W. Biederman 2018-01-19 1060 lsb = PAGE_SHIFT;
40e553946 Eric W. Biederman 2018-01-19 1061 force_sig_mceerr(BUS_MCEERR_AR, (void __user *)address, lsb, tsk);
40e553946 Eric W. Biederman 2018-01-19 1062 return;
a6e04aa92 Andi Kleen 2009-09-16 1063 }
a6e04aa92 Andi Kleen 2009-09-16 1064 #endif
b4fd52f25 Eric W. Biederman 2018-09-18 1065 force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, tsk);
92181f190 Nick Piggin 2009-01-20 1066 }
92181f190 Nick Piggin 2009-01-20 1067
3a13c4d76 Johannes Weiner 2013-09-12 1068 static noinline void
2d4a71676 Ingo Molnar 2009-02-20 1069 mm_fault_error(struct pt_regs *regs, unsigned long error_code,
25c102d80 Eric W. Biederman 2018-09-18 1070 unsigned long address, vm_fault_t fault)
92181f190 Nick Piggin 2009-01-20 1071 {
1067f0309 Ricardo Neri 2017-10-27 1072 if (fatal_signal_pending(current) && !(error_code & X86_PF_USER)) {
4fc349011 Andy Lutomirski 2011-11-07 1073 no_context(regs, error_code, address, 0, 0);
3a13c4d76 Johannes Weiner 2013-09-12 1074 return;
b80ef10e8 KOSAKI Motohiro 2011-05-26 1075 }
b80ef10e8 KOSAKI Motohiro 2011-05-26 1076
2d4a71676 Ingo Molnar 2009-02-20 1077 if (fault & VM_FAULT_OOM) {
f86268549 Andrey Vagin 2011-03-09 1078 /* Kernel mode? Handle exceptions or die: */
1067f0309 Ricardo Neri 2017-10-27 1079 if (!(error_code & X86_PF_USER)) {
4fc349011 Andy Lutomirski 2011-11-07 1080 no_context(regs, error_code, address,
4fc349011 Andy Lutomirski 2011-11-07 1081 SIGSEGV, SEGV_MAPERR);
3a13c4d76 Johannes Weiner 2013-09-12 1082 return;
f86268549 Andrey Vagin 2011-03-09 1083 }
f86268549 Andrey Vagin 2011-03-09 1084
c2d23f919 David Rientjes 2012-12-12 1085 /*
c2d23f919 David Rientjes 2012-12-12 1086 * We ran out of memory, call the OOM killer, and return the
c2d23f919 David Rientjes 2012-12-12 1087 * userspace (which will retry the fault, or kill us if we got
c2d23f919 David Rientjes 2012-12-12 1088 * oom-killed):
c2d23f919 David Rientjes 2012-12-12 1089 */
c2d23f919 David Rientjes 2012-12-12 1090 pagefault_out_of_memory();
2d4a71676 Ingo Molnar 2009-02-20 1091 } else {
f672b49b0 Andi Kleen 2010-09-27 1092 if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|
f672b49b0 Andi Kleen 2010-09-27 1093 VM_FAULT_HWPOISON_LARGE))
27274f731 Eric W. Biederman 2018-09-18 @1094 do_sigbus(regs, error_code, address, fault);
33692f275 Linus Torvalds 2015-01-29 1095 else if (fault & VM_FAULT_SIGSEGV)
768fd9c69 Eric W. Biederman 2018-09-18 1096 bad_area_nosemaphore(regs, error_code, address);
92181f190 Nick Piggin 2009-01-20 1097 else
92181f190 Nick Piggin 2009-01-20 1098 BUG();
92181f190 Nick Piggin 2009-01-20 1099 }
2d4a71676 Ingo Molnar 2009-02-20 1100 }
92181f190 Nick Piggin 2009-01-20 1101
:::::: The code at line 1051 was first introduced by commit
:::::: f672b49b07a4a152fc4251f2aec6b4d05164c4cd x86: HWPOISON: Report correct address granuality for huge hwpoison faults
:::::: TO: Andi Kleen <ak@linux.intel.com>
:::::: CC: Andi Kleen <ak@linux.intel.com>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Hi Souptick,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on linus/master]
[also build test WARNING on v5.0-rc1 next-20190109]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Souptick-Joarder/mm-Create-the-new-vm_fault_t-type/20190109-154216
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-7 (Debian 7.3.0-1) 7.3.0
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64
All warnings (new ones prefixed by >>):
>> kernel/memremap.c:46:34: warning: incorrect type in return expression (different base types)
kernel/memremap.c:46:34: expected restricted vm_fault_t
kernel/memremap.c:46:34: got int
vim +46 kernel/memremap.c
9476df7d Dan Williams 2016-01-15 19
5042db43 Jérôme Glisse 2017-09-08 20 #if IS_ENABLED(CONFIG_DEVICE_PRIVATE)
2b740303 Souptick Joarder 2018-08-23 21 vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
5042db43 Jérôme Glisse 2017-09-08 22 unsigned long addr,
5042db43 Jérôme Glisse 2017-09-08 23 swp_entry_t entry,
5042db43 Jérôme Glisse 2017-09-08 24 unsigned int flags,
5042db43 Jérôme Glisse 2017-09-08 25 pmd_t *pmdp)
5042db43 Jérôme Glisse 2017-09-08 26 {
5042db43 Jérôme Glisse 2017-09-08 27 struct page *page = device_private_entry_to_page(entry);
063a7d1d Dan Williams 2018-12-28 28 struct hmm_devmem *devmem;
063a7d1d Dan Williams 2018-12-28 29
063a7d1d Dan Williams 2018-12-28 30 devmem = container_of(page->pgmap, typeof(*devmem), pagemap);
5042db43 Jérôme Glisse 2017-09-08 31
5042db43 Jérôme Glisse 2017-09-08 32 /*
5042db43 Jérôme Glisse 2017-09-08 33 * The page_fault() callback must migrate page back to system memory
5042db43 Jérôme Glisse 2017-09-08 34 * so that CPU can access it. This might fail for various reasons
5042db43 Jérôme Glisse 2017-09-08 35 * (device issue, device was unsafely unplugged, ...). When such
5042db43 Jérôme Glisse 2017-09-08 36 * error conditions happen, the callback must return VM_FAULT_SIGBUS.
5042db43 Jérôme Glisse 2017-09-08 37 *
5042db43 Jérôme Glisse 2017-09-08 38 * Note that because memory cgroup charges are accounted to the device
5042db43 Jérôme Glisse 2017-09-08 39 * memory, this should never fail because of memory restrictions (but
5042db43 Jérôme Glisse 2017-09-08 40 * allocation of regular system page might still fail because we are
5042db43 Jérôme Glisse 2017-09-08 41 * out of memory).
5042db43 Jérôme Glisse 2017-09-08 42 *
5042db43 Jérôme Glisse 2017-09-08 43 * There is a more in-depth description of what that callback can and
5042db43 Jérôme Glisse 2017-09-08 44 * cannot do, in include/linux/memremap.h
5042db43 Jérôme Glisse 2017-09-08 45 */
063a7d1d Dan Williams 2018-12-28 @46 return devmem->page_fault(vma, addr, page, flags, pmdp);
5042db43 Jérôme Glisse 2017-09-08 47 }
5042db43 Jérôme Glisse 2017-09-08 48 EXPORT_SYMBOL(device_private_entry_fault);
5042db43 Jérôme Glisse 2017-09-08 49 #endif /* CONFIG_DEVICE_PRIVATE */
5042db43 Jérôme Glisse 2017-09-08 50
:::::: The code at line 46 was first introduced by commit
:::::: 063a7d1d3623db31ca5d2309cab6030ebf93b72f mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
:::::: TO: Dan Williams <dan.j.williams@intel.com>
:::::: CC: Linus Torvalds <torvalds@linux-foundation.org>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
diff --git a/include/linux/mm.h b/include/linux/mm.h index fcf9cc9..511a3ce 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1267,52 +1267,6 @@ static inline void clear_page_pfmemalloc(struct page *page) } /* - * Different kinds of faults, as returned by handle_mm_fault(). - * Used to decide whether a process gets delivered SIGBUS or - * just gets major/minor fault counters bumped up. - */ - -#define VM_FAULT_OOM 0x0001 -#define VM_FAULT_SIGBUS 0x0002 -#define VM_FAULT_MAJOR 0x0004 -#define VM_FAULT_WRITE 0x0008 /* Special case for get_user_pages */ -#define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned small page */ -#define VM_FAULT_HWPOISON_LARGE 0x0020 /* Hit poisoned large page. Index encoded in upper bits */ -#define VM_FAULT_SIGSEGV 0x0040 - -#define VM_FAULT_NOPAGE 0x0100 /* ->fault installed the pte, not return page */ -#define VM_FAULT_LOCKED 0x0200 /* ->fault locked the returned page */ -#define VM_FAULT_RETRY 0x0400 /* ->fault blocked, must retry */ -#define VM_FAULT_FALLBACK 0x0800 /* huge page fault failed, fall back to small */ -#define VM_FAULT_DONE_COW 0x1000 /* ->fault has fully handled COW */ -#define VM_FAULT_NEEDDSYNC 0x2000 /* ->fault did not modify page tables - * and needs fsync() to complete (for - * synchronous page faults in DAX) */ - -#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \ - VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \ - VM_FAULT_FALLBACK) - -#define VM_FAULT_RESULT_TRACE \ - { VM_FAULT_OOM, "OOM" }, \ - { VM_FAULT_SIGBUS, "SIGBUS" }, \ - { VM_FAULT_MAJOR, "MAJOR" }, \ - { VM_FAULT_WRITE, "WRITE" }, \ - { VM_FAULT_HWPOISON, "HWPOISON" }, \ - { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ - { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ - { VM_FAULT_NOPAGE, "NOPAGE" }, \ - { VM_FAULT_LOCKED, "LOCKED" }, \ - { VM_FAULT_RETRY, "RETRY" }, \ - { VM_FAULT_FALLBACK, "FALLBACK" }, \ - { VM_FAULT_DONE_COW, "DONE_COW" }, \ - { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } - -/* Encode hstate index for a hwpoisoned large page */ -#define VM_FAULT_SET_HINDEX(x) ((x) << 12) -#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf) - -/* * Can be called by the pagefault handler when it gets a VM_FAULT_OOM. */ extern void pagefault_out_of_memory(void); diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 5ed8f62..cb25016 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -22,7 +22,6 @@ #endif #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1)) -typedef int vm_fault_t; struct address_space; struct mem_cgroup; @@ -609,6 +608,78 @@ static inline bool mm_tlb_flush_nested(struct mm_struct *mm) struct vm_fault; +/** + * typedef vm_fault_t - Return type for page fault handlers. + * + * Page fault handlers return a bitmask of %VM_FAULT values. + */ +typedef __bitwise unsigned int vm_fault_t; + +/** + * enum vm_fault_reason - Page fault handlers return a bitmask of + * these values to tell the core VM what happened when handling the + * fault. Used to decide whether a process gets delivered SIGBUS or + * just gets major/minor fault counters bumped up. + * + * @VM_FAULT_OOM: Out Of Memory + * @VM_FAULT_SIGBUS: Bad access + * @VM_FAULT_MAJOR: Page read from storage + * @VM_FAULT_WRITE: Special case for get_user_pages + * @VM_FAULT_HWPOISON: Hit poisoned small page + * @VM_FAULT_HWPOISON_LARGE: Hit poisoned large page. Index encoded + * in upper bits + * @VM_FAULT_SIGSEGV: segmentation fault + * @VM_FAULT_NOPAGE: ->fault installed the pte, not return page + * @VM_FAULT_LOCKED: ->fault locked the returned page + * @VM_FAULT_RETRY: ->fault blocked, must retry + * @VM_FAULT_FALLBACK: huge page fault failed, fall back to small + * @VM_FAULT_DONE_COW: ->fault has fully handled COW + * @VM_FAULT_NEEDDSYNC: ->fault did not modify page tables and needs + * fsync() to complete (for synchronous page faults + * in DAX) + * @VM_FAULT_HINDEX_MASK: mask HINDEX value + * + */ +enum vm_fault_reason { + VM_FAULT_OOM = (__force vm_fault_t)0x000001, + VM_FAULT_SIGBUS = (__force vm_fault_t)0x000002, + VM_FAULT_MAJOR = (__force vm_fault_t)0x000004, + VM_FAULT_WRITE = (__force vm_fault_t)0x000008, + VM_FAULT_HWPOISON = (__force vm_fault_t)0x000010, + VM_FAULT_HWPOISON_LARGE = (__force vm_fault_t)0x000020, + VM_FAULT_SIGSEGV = (__force vm_fault_t)0x000040, + VM_FAULT_NOPAGE = (__force vm_fault_t)0x000100, + VM_FAULT_LOCKED = (__force vm_fault_t)0x000200, + VM_FAULT_RETRY = (__force vm_fault_t)0x000400, + VM_FAULT_FALLBACK = (__force vm_fault_t)0x000800, + VM_FAULT_DONE_COW = (__force vm_fault_t)0x001000, + VM_FAULT_NEEDDSYNC = (__force vm_fault_t)0x002000, + VM_FAULT_HINDEX_MASK = (__force vm_fault_t)0x0f0000, +}; + +/* Encode hstate index for a hwpoisoned large page */ +#define VM_FAULT_SET_HINDEX(x) ((__force vm_fault_t)((x) << 16)) +#define VM_FAULT_GET_HINDEX(x) (((x) >> 16) & 0xf) + +#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | \ + VM_FAULT_SIGSEGV | VM_FAULT_HWPOISON | \ + VM_FAULT_HWPOISON_LARGE | VM_FAULT_FALLBACK) + +#define VM_FAULT_RESULT_TRACE \ + { VM_FAULT_OOM, "OOM" }, \ + { VM_FAULT_SIGBUS, "SIGBUS" }, \ + { VM_FAULT_MAJOR, "MAJOR" }, \ + { VM_FAULT_WRITE, "WRITE" }, \ + { VM_FAULT_HWPOISON, "HWPOISON" }, \ + { VM_FAULT_HWPOISON_LARGE, "HWPOISON_LARGE" }, \ + { VM_FAULT_SIGSEGV, "SIGSEGV" }, \ + { VM_FAULT_NOPAGE, "NOPAGE" }, \ + { VM_FAULT_LOCKED, "LOCKED" }, \ + { VM_FAULT_RETRY, "RETRY" }, \ + { VM_FAULT_FALLBACK, "FALLBACK" }, \ + { VM_FAULT_DONE_COW, "DONE_COW" }, \ + { VM_FAULT_NEEDDSYNC, "NEEDDSYNC" } + struct vm_special_mapping { const char *name; /* The name, e.g. "[vdso]". */