From: Dave Hansen <dave.hansen@intel.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>,
linux-kernel@vger.kernel.org
Cc: Al Viro <viro@zeniv.linux.org.uk>,
Oleg Nesterov <oleg@redhat.com>,
linux-arch@vger.kernel.org, Ram Pai <linuxram@us.ibm.com>
Subject: Re: [PATCH 13/22] signal: Move addr_lsb into the _sigfault union for clarity
Date: Fri, 16 Mar 2018 12:24:44 -0700 [thread overview]
Message-ID: <818f8945-f990-a770-476e-f82bdc77dbda@intel.com> (raw)
In-Reply-To: <29eb3438-0891-36ee-e5f6-36e26ccf2b89@intel.com>
[-- Attachment #1: Type: text/plain, Size: 1085 bytes --]
On 03/16/2018 12:00 PM, Dave Hansen wrote:
> On 01/15/2018 04:40 PM, Eric W. Biederman wrote:
>> The addr_lsb fields is only valid and available when the
>> signal is SIGBUS and the si_code is BUS_MCEERR_AR or BUS_MCEERR_AO.
>> Document this with a comment and place the field in the _sigfault union
>> to make this clear.
>>
>> All of the fields stay in the same physical location so both the old
>> and new definitions of struct siginfo will continue to work.
>
> This breaks the ABI and breaks protection keys. The physical locations
> *DO* change.
>
> Before this patch:
>
> #define si_pkey _sifields._sigfault._pkey
> (gdb) print &((siginfo_t *)0)->_sifields._sigfault._pkey
> $1 = (__u32 *) 0x20 <irq_stack_union+32>
>
> and after:
>
> +#define si_pkey _sifields._sigfault._addr_pkey._pkey
> (gdb) print &((siginfo_t *)0)->_sifields._sigfault._addr_pkey._pkey
> $1 = (__u32 *) 0x1c
>
> Can we revert this, please?
It does not revert cleanly so I reverted it manually. Patch doing that
is attached. Should we do this, or is there a better option?
[-- Attachment #2: revert-b68a68d3dcc15ebbf23cbe91af1abf57591bd96b.patch --]
[-- Type: text/x-patch, Size: 2642 bytes --]
index e698ec1..8f8e3ef 100644
---
b/include/linux/compat.h | 12 ++----------
b/include/uapi/asm-generic/siginfo.h | 14 +++-----------
2 files changed, 5 insertions(+), 21 deletions(-)
diff -puN include/linux/compat.h~revert-b68a68d3dcc15ebbf23cbe91af1abf57591bd96b include/linux/compat.h
--- a/include/linux/compat.h~revert-b68a68d3dcc15ebbf23cbe91af1abf57591bd96b 2018-03-16 12:02:22.156310058 -0700
+++ b/include/linux/compat.h 2018-03-16 12:03:11.341309936 -0700
@@ -222,23 +222,15 @@ typedef struct compat_siginfo {
#ifdef __ARCH_SI_TRAPNO
int _trapno; /* TRAP # which caused the signal */
#endif
+ short int _addr_lsb; /* Valid LSB of the reported address. */
union {
- /*
- * used when si_code=BUS_MCEERR_AR or
- * used when si_code=BUS_MCEERR_AO
- */
- short int _addr_lsb; /* Valid LSB of the reported address. */
/* used when si_code=SEGV_BNDERR */
struct {
- compat_uptr_t _dummy_bnd;
compat_uptr_t _lower;
compat_uptr_t _upper;
} _addr_bnd;
/* used when si_code=SEGV_PKUERR */
- struct {
- compat_uptr_t _dummy_pkey;
- u32 _pkey;
- } _addr_pkey;
+ u32 _pkey;
};
} _sigfault;
diff -puN include/uapi/asm-generic/siginfo.h~revert-b68a68d3dcc15ebbf23cbe91af1abf57591bd96b include/uapi/asm-generic/siginfo.h
--- a/include/uapi/asm-generic/siginfo.h~revert-b68a68d3dcc15ebbf23cbe91af1abf57591bd96b 2018-03-16 12:02:22.157310058 -0700
+++ b/include/uapi/asm-generic/siginfo.h 2018-03-16 12:03:37.071309872 -0700
@@ -94,23 +94,15 @@ typedef struct siginfo {
unsigned int _flags; /* see ia64 si_flags */
unsigned long _isr; /* isr */
#endif
+ short _addr_lsb; /* LSB of the reported address */
union {
- /*
- * used when si_code=BUS_MCEERR_AR or
- * used when si_code=BUS_MCEERR_AO
- */
- short _addr_lsb; /* LSB of the reported address */
/* used when si_code=SEGV_BNDERR */
struct {
- void *_dummy_bnd;
void __user *_lower;
void __user *_upper;
} _addr_bnd;
/* used when si_code=SEGV_PKUERR */
- struct {
- void *_dummy_pkey;
- __u32 _pkey;
- } _addr_pkey;
+ __u32 _pkey;
};
} _sigfault;
@@ -150,7 +142,7 @@ typedef struct siginfo {
#define si_addr_lsb _sifields._sigfault._addr_lsb
#define si_lower _sifields._sigfault._addr_bnd._lower
#define si_upper _sifields._sigfault._addr_bnd._upper
-#define si_pkey _sifields._sigfault._addr_pkey._pkey
+#define si_pkey _sifields._sigfault._pkey
#define si_band _sifields._sigpoll._band
#define si_fd _sifields._sigpoll._fd
#define si_call_addr _sifields._sigsys._call_addr
_
next prev parent reply other threads:[~2018-03-16 19:24 UTC|newest]
Thread overview: 89+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 0:57 [PATCH 00/11] siginfo fixes/cleanups esp SI_USER Eric W. Biederman
2018-01-12 0:59 ` [PATCH 01/11] signal: Simplify and fix kdb_send_sig Eric W. Biederman
2018-01-12 0:59 ` [PATCH 02/11] signal/sh: Ensure si_signo is initialized in do_divide_error Eric W. Biederman
2018-01-12 0:59 ` [PATCH 03/11] signal/openrisc: Fix do_unaligned_access to send the proper signal Eric W. Biederman
2018-01-12 13:25 ` Stafford Horne
2018-01-12 17:37 ` Eric W. Biederman
2018-01-12 0:59 ` [PATCH 04/11] signal/parisc: Document a conflict with SI_USER with SIGFPE Eric W. Biederman
2018-01-12 22:29 ` Helge Deller
2018-01-13 21:06 ` Eric W. Biederman
2018-01-14 1:46 ` Eric W. Biederman
2018-02-23 0:15 ` Eric W. Biederman
2018-02-25 19:49 ` Helge Deller
2018-02-27 2:19 ` Eric W. Biederman
2018-01-12 0:59 ` [PATCH 05/11] signal/metag: " Eric W. Biederman
2018-01-12 0:59 ` [PATCH 06/11] signal/powerpc: Document conflicts with SI_USER and SIGFPE and SIGTRAP Eric W. Biederman
2018-01-12 0:59 ` [PATCH 07/11] signal/arm64: Document conflicts with SI_USER and SIGFPE,SIGTRAP,SIGBUS Eric W. Biederman
2018-01-15 16:30 ` [PATCH 07/11] signal/arm64: Document conflicts with SI_USER and SIGFPE, SIGTRAP, SIGBUS Dave Martin
2018-01-15 17:23 ` Eric W. Biederman
2018-01-16 17:24 ` Dave Martin
2018-01-16 22:28 ` Eric W. Biederman
2018-01-17 11:46 ` Dave Martin
2018-01-17 11:57 ` Russell King - ARM Linux
2018-01-17 12:15 ` Dave Martin
2018-01-17 12:37 ` Russell King - ARM Linux
2018-01-17 15:37 ` Dave Martin
2018-01-17 15:49 ` Russell King - ARM Linux
2018-01-17 16:11 ` Dave Martin
2018-01-17 16:45 ` Eric W. Biederman
2018-01-17 17:14 ` Russell King - ARM Linux
2018-01-24 21:28 ` Eric W. Biederman
2018-01-17 17:17 ` Dave Martin
2018-01-17 17:24 ` Eric W. Biederman
2018-01-17 17:39 ` Dave Martin
2018-01-15 19:30 ` James Morse
2018-01-12 0:59 ` [PATCH 08/11] signal/arm: Document conflicts with SI_USER and SIGFPE Eric W. Biederman
2018-01-15 17:49 ` Russell King - ARM Linux
2018-01-15 20:12 ` Eric W. Biederman
2018-01-16 17:41 ` Dave Martin
2018-01-19 12:05 ` Dave Martin
2018-01-12 0:59 ` [PATCH 09/11] signal: Reduce copy_siginfo to just a memcpy Eric W. Biederman
2018-01-12 0:59 ` [PATCH 10/11] signal: Introduce clear_siginfo Eric W. Biederman
2018-01-12 0:59 ` [PATCH 11/11] signal: Ensure generic siginfos the kernel sends have all bits initialized Eric W. Biederman
2018-01-12 20:29 ` [PATCH 0/2] siginfo fixes Eric W. Biederman
2018-01-12 20:31 ` [PATCH 1/2] mn10300/misalignment: Use SIGSEGV SEGV_MAPERR to report a failed user copy Eric W. Biederman
2018-01-12 20:31 ` [PATCH 2/2] x86/mm/pkeys: Fix fill_sig_info_pkey Eric W. Biederman
2018-01-14 11:44 ` [tip:x86/urgent] " tip-bot for Eric W. Biederman
2018-01-16 0:39 ` [PATCH 00/22] siginfo unification Eric W. Biederman
2018-01-16 0:39 ` [PATCH 01/22] signal: Document all of the signals that use the _sigfault union member Eric W. Biederman
2018-01-16 0:39 ` [PATCH 02/22] signal: Document the strange si_codes used by ptrace event stops Eric W. Biederman
2018-01-16 0:39 ` [PATCH 03/22] signal: Document glibc's si_code of SI_ASYNCNL Eric W. Biederman
2018-01-16 0:39 ` [PATCH 04/22] signal: Ensure no siginfo union member increases the size of struct siginfo Eric W. Biederman
2018-01-16 0:39 ` [PATCH 05/22] signal: Clear si_sys_private before copying siginfo to userspace Eric W. Biederman
2018-01-16 0:39 ` [PATCH 06/22] signal: Remove _sys_private and _overrun_incr from struct compat_siginfo Eric W. Biederman
2018-01-16 0:39 ` [PATCH 07/22] ia64/signal: switch to generic struct siginfo Eric W. Biederman
2018-01-16 0:39 ` [PATCH 08/22] signal/ia64: switch the last arch-specific copy_siginfo_to_user() to generic version Eric W. Biederman
2018-01-16 0:39 ` [PATCH 09/22] signal/mips: switch mips to generic siginfo Eric W. Biederman
2018-01-16 0:39 ` [PATCH 10/22] signal: Remove unnecessary ifdefs now that there is only one struct siginfo Eric W. Biederman
2018-01-16 0:39 ` [PATCH 11/22] signal: kill __ARCH_SI_UID_T Eric W. Biederman
2018-01-16 0:39 ` [PATCH 12/22] signal: unify compat_siginfo_t Eric W. Biederman
2018-01-16 0:40 ` [PATCH 13/22] signal: Move addr_lsb into the _sigfault union for clarity Eric W. Biederman
2018-03-16 19:00 ` Dave Hansen
2018-03-16 19:24 ` Dave Hansen [this message]
2018-03-16 20:06 ` Eric W. Biederman
2018-03-16 20:33 ` Dave Hansen
2018-03-16 21:08 ` Eric W. Biederman
2018-01-16 0:40 ` [PATCH 14/22] signal/powerpc: Remove redefinition of NSIGTRAP on powerpc Eric W. Biederman
2018-01-16 0:40 ` [PATCH 15/22] signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h Eric W. Biederman
2018-01-16 0:40 ` [PATCH 16/22] signal/frv: Move the frv " Eric W. Biederman
2018-01-16 0:40 ` [PATCH 17/22] signal/tile: Move the tile " Eric W. Biederman
2018-01-16 0:40 ` [PATCH 18/22] signal/blackfin: Move the blackfin " Eric W. Biederman
2018-01-16 0:40 ` [PATCH 19/22] signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED Eric W. Biederman
2018-01-16 0:40 ` [PATCH 20/22] signal: Unify and correct copy_siginfo_from_user32 Eric W. Biederman
2018-01-16 0:40 ` [PATCH 21/22] signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32 Eric W. Biederman
2018-01-16 0:40 ` [PATCH 22/22] signal: Unify and correct copy_siginfo_to_user32 Eric W. Biederman
2018-01-19 18:03 ` Al Viro
2018-01-19 21:04 ` Eric W. Biederman
2018-01-23 21:05 ` [PATCH 00/10] siginfo infrastructure Eric W. Biederman
2018-01-23 21:07 ` [PATCH 01/10] ptrace: Use copy_siginfo in setsiginfo and getsiginfo Eric W. Biederman
2018-01-23 21:07 ` [PATCH 02/10] signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered Eric W. Biederman
2018-01-23 21:07 ` [PATCH 03/10] signal: Don't use structure initializers for struct siginfo Eric W. Biederman
2018-01-23 21:07 ` [PATCH 04/10] signal: Replace memset(info,...) with clear_siginfo for clarity Eric W. Biederman
2018-01-23 21:07 ` [PATCH 05/10] signal: Add send_sig_fault and force_sig_fault Eric W. Biederman
2018-01-23 21:07 ` [PATCH 06/10] signal: Helpers for faults with specialized siginfo layouts Eric W. Biederman
2018-01-24 19:26 ` Ram Pai
2018-01-24 20:54 ` Eric W. Biederman
2018-01-23 21:07 ` [PATCH 07/10] signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap Eric W. Biederman
2018-01-23 21:07 ` [PATCH 08/10] signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed Eric W. Biederman
2018-01-23 21:07 ` [PATCH 09/10] mm/memory_failure: Remove unused trapno from memory_failure Eric W. Biederman
2018-01-23 21:07 ` [PATCH 10/10] signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr Eric W. Biederman
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