Al Viro
653d48b221
arm: fix really nasty sigreturn bug ...
If a signal hits us outside of a syscall and another gets delivered
when we are in sigreturn (e.g. because it had been in sa_mask for
the first one and got sent to us while we'd been in the first handler),
we have a chance of returning from the second handler to location one
insn prior to where we ought to return. If r0 happens to contain -513
(-ERESTARTNOINTR), sigreturn will get confused into doing restart
syscall song and dance.
Incredible joy to debug, since it manifests as random, infrequent and
very hard to reproduce double execution of instructions in userland
code...
The fix is simple - mark it "don't bother with restarts" in wrapper,
i.e. set r8 to 0 in sys_sigreturn and sys_rt_sigreturn wrappers,
suppressing the syscall restart handling on return from these guys.
They can't legitimately return a restart-worthy error anyway.
Testcase:
#include <unistd.h>
#include <signal.h>
#include <stdlib.h>
#include <sys/time.h>
#include <errno.h>
void f(int n)
{
__asm__ __volatile__(
"ldr r0, [%0]\n"
"b 1f\n"
"b 2f\n"
"1:b .\n"
"2:\n" : : "r"(&n));
}
void handler1(int sig) { }
void handler2(int sig) { raise(1); }
void handler3(int sig) { exit(0); }
main()
{
struct sigaction s = {.sa_handler = handler2};
struct itimerval t1 = { .it_value = {1} };
struct itimerval t2 = { .it_value = {2} };
signal(1, handler1);
sigemptyset(&s.sa_mask);
sigaddset(&s.sa_mask, 1);
sigaction(SIGALRM, &s, NULL);
signal(SIGVTALRM, handler3);
setitimer(ITIMER_REAL, &t1, NULL);
setitimer(ITIMER_VIRTUAL, &t2, NULL);
f(-513); /* -ERESTARTNOINTR */
write(1, "buggered\n", 9);
return 1;
}
Signed-off-by: Al Viro <[email protected] >
Acked-by: Russell King <[email protected] >
Cc: [email protected] [email protected] >
2010-09-17 10:22:18 -07:00
ARM: Partially revert "Auto calculate ZRELADDR and provide option for exceptions"
2010-09-09 22:39:41 +01:00
Revert "[ARM] pxa: remove now unnecessary dma_needs_bounce()"
2010-09-08 12:28:39 +01:00
omap: Fix omap_4430sdp_defconfig for make oldconfig
2010-08-16 09:22:04 +03:00
include /asm
Revert "[ARM] pxa: remove now unnecessary dma_needs_bounce()"
2010-09-08 12:28:39 +01:00
arm: fix really nasty sigreturn bug
2010-09-17 10:22:18 -07:00
Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
2010-08-03 14:31:24 -07:00
ARM: Remove DISCONTIGMEM support
2010-07-16 10:57:35 +01:00
AT91: at91sam9261ek: remove C99 comments but keep information
2010-09-10 14:36:06 +02:00
ARM: AMBA: Add pclk definition for platforms using primecells
2010-07-22 09:55:38 +01:00
ARM: 6283/1: Remove useless PCIO_BASE definitions
2010-08-05 10:35:49 +01:00
ARM: cns3xxx: Add support for AHCI controllers
2010-06-08 17:37:09 +04:00
Merge branch 'davinci-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci
2010-08-08 10:00:55 -07:00
[ARM] Dove: platform device registration for the sdio interfaces
2010-07-16 22:01:59 -04:00
ARM: 6359/1: ep93xx: move clock initialization earlier
2010-09-08 12:28:39 +01:00
ARM: 6233/1: Delete a wrong redundant right parenthesis
2010-07-22 09:20:50 +01:00
ARM: 6283/1: Remove useless PCIO_BASE definitions
2010-08-05 10:35:49 +01:00
ARM: imx: fix build failure concerning otg/ulpi
2010-08-23 20:50:17 -07:00
ARM: 6283/1: Remove useless PCIO_BASE definitions
2010-08-05 10:35:49 +01:00
Merge branch 'misc' into devel
2010-07-31 14:20:02 +01:00
Merge git://git.infradead.org/mtd-2.6
2010-08-15 17:32:47 -07:00
ARM: 6283/1: Remove useless PCIO_BASE definitions
2010-08-05 10:35:49 +01:00
ARM: 6269/1: Add 'code' parameter for hook_fault_code()
2010-07-27 10:48:34 +01:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
2010-08-07 17:07:31 -07:00
ARM: 6269/1: Add 'code' parameter for hook_fault_code()
2010-07-27 10:48:34 +01:00
ARM: Remove DISCONTIGMEM support
2010-07-16 10:57:35 +01:00
ARM: LPC32XX: Arch config menu supoport and makefiles
2010-07-27 08:46:22 -07:00
[ARM] mmp: move declarations into SoC specific header file from common.h
2010-08-05 14:34:46 +08:00
Merge branch 'msm-core' of git://codeaurora.org/quic/kernel/dwalker/linux-msm
2010-08-12 10:07:32 -07:00
Merge branch 'imx-for-2.6.36' of git://git.pengutronix.de/git/imx/linux-2.6
2010-09-01 10:08:50 +01:00
mx5/clock: fix clear bit fields issue in _clk_ccgr_disable function
2010-08-21 12:22:43 +02:00
Merge branch 'imx-for-2.6.36' of git://git.pengutronix.de/git/imx/linux-2.6
2010-09-01 10:08:50 +01:00
ARM: mxc91231: remove paragraphs with old address of the FSF
2010-06-30 09:00:27 +02:00
ARM: AMBA: Add pclk definition for platforms using primecells
2010-07-22 09:55:38 +01:00
ARM: 6263/1: ns9xxx: fix FTBFS for zImage
2010-07-26 10:33:07 +01:00
Merge branch 'v2.6.35-omap-mailbox-for-next' of git://gitorious.org/~doyu/lk/mainline into omap-for-linus
2010-08-04 16:10:38 +03:00
OMAP3: PM: ensure IO wakeups are properly disabled
2010-08-16 09:22:05 +03:00
ARM: Fix gen_nand probe structures contents
2010-08-12 02:21:18 +01:00
ARM: pxa: fix CI_HSYNC and CI_VSYNC MFP defines for pxa300
2010-08-30 09:59:43 +08:00
Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
2010-08-03 14:31:24 -07:00
mach-s3c24a0/include /mach
ARM: SAMSUNG: Fix on build warning regarding VMALLOC_END type
2010-08-27 15:28:38 +09:00
ARM: SAMSUNG: Fix on build warning regarding VMALLOC_END type
2010-08-27 15:28:38 +09:00
ARM: Remove DISCONTIGMEM support
2010-07-16 10:57:35 +01:00
s3c-fb: add device name initialization
2010-08-11 08:59:10 -07:00
panic: keep blinking in spite of long spin timer mode
2010-08-11 08:59:22 -07:00
s3c-fb: add device name initialization
2010-08-11 08:59:10 -07:00
ARM: SAMSUNG: Fix on build warning regarding VMALLOC_END type
2010-08-27 15:28:38 +09:00
ARM: SAMSUNG: Fix on build warning regarding VMALLOC_END type
2010-08-27 15:28:38 +09:00
Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm
2010-08-11 09:13:19 -07:00
ARM: S5P: VMALLOC_END should be unsigned long
2010-08-23 10:50:36 +09:00
ARM: S5PV310: Fix on Secondary CPU startup
2010-08-27 18:29:58 +09:00
Merge branch 'devel' of git://git.kernel.org/pub/scm/linux/kernel/git/ycmiao/pxa-linux-2.6 into devel-stable
2010-08-06 18:10:25 +01:00
Merge branches 'at91', 'ep93xx', 'kexec', 'iop', 'lmb', 'nomadik', 'nuc', 'pl', 'spear' and 'versatile' into devel
2010-07-31 14:19:35 +01:00
ARM: mach-shmobile: ap4evb: fix write protect for SDHI1
2010-08-20 20:41:23 +09:00
ARM: AMBA: Add pclk definition for platforms using primecells
2010-07-22 09:55:38 +01:00
ARM: AMBA: Add pclk definition for platforms using primecells
2010-07-22 09:55:38 +01:00
arm: tegra: VMALLOC_END should be unsigned long
2010-08-22 12:54:23 -07:00
ARM: 6297/1: move U300 timer to dynamic clock lookup
2010-08-10 22:10:56 +01:00
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx
2010-08-09 21:00:07 -07:00
ARM: 6282/1: Remove useless definitions from versatile hardware.h
2010-08-05 10:35:49 +01:00
Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
2010-08-03 14:31:24 -07:00
i2c/nuc900: add i2c driver support for nuc900
2010-08-11 00:34:38 +01:00
ARM: Ensure PTE modifications via dma_alloc_coherent are visible
2010-09-08 16:27:56 +01:00
ARM: arch/arm/nwfpe/fpsr.h: Checkpatch cleanup
2010-05-24 20:40:12 +01:00
Merge branch 'misc' into devel
2010-07-31 14:20:02 +01:00
ARM: imx: set cache line size to 64 bytes for i.MX5
2010-08-21 12:22:43 +02:00
Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx
2010-08-09 21:00:07 -07:00
omap: Fix sev instruction usage for multi-omap
2010-08-16 09:22:04 +03:00
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
2010-08-07 17:07:31 -07:00
ARM: pxa: Make id const in pwm_probe()
2010-08-30 09:59:44 +08:00
Merge branch 'master' into for-next
2010-06-16 18:08:13 +02:00
ARM: S5PV310: Fix on Secondary CPU startup
2010-08-27 18:29:58 +09:00
s5pc110: SDHCI-s3c can override host capabilities
2010-08-20 09:34:55 -07:00
Merge branch 'master' into for-next
2010-08-04 15:14:38 +02:00
ARM: 6264/1: fix Versatile Express LED oversight
2010-07-26 10:48:34 +01:00
ARM: Update mach-types
2010-09-09 22:49:26 +01:00
ARM: 6203/1: Make VFPv3 usable on ARMv6
2010-07-09 14:41:34 +01:00
ARM: Partially revert "Auto calculate ZRELADDR and provide option for exceptions"
2010-09-09 22:39:41 +01:00
ARM: 6328/1: Build with -fno-dwarf2-cfi-asm
2010-08-14 23:58:43 +01:00
653d48b221